What repeaters can you access?

[Stephen Thomas Cole]

I've been mulling for a while that it'd be nice to have a QSO with some of
the ukra/ukram users, and a very nice chat just now with a former ukra
poster, Andy G0FTD, on GB3RE suggests that repeaters might be a good place
to start!

I'm not in a great spot at this QTH for VHF/UHF, there's a lot of geography
in my way in most directions. But I can access the following:

GB3IK
GB3KN
GB3DA
GB3KI on 2m

& GB3RE on 70cm.

Can anybody else open any of these up?

In my car, at the top of the valley here, I can open up many of the London
repeaters, as well as Ipswich and Norfolk (with a good wind behind me) and
likely more. Would be great if there's anyone who can get in to the
repeaters I can work from home, though!

--
STC // M0TEY // twitter.com/ukradioamateur

[Wimpie]

El 13-Mar-16 a las 17:16, Stephen Thomas Cole escribió:

If you are near the coast towards Netherlands, and there is some tropo,
try the reach PI2NOS, 430.125 MHz (+1.6 MHz shift for the input frequency).

The system consists of about 17 receivers and 3 transmitters. The
transmitters operate on a single frequency (430.125 MHz). More info
about the system you will find at:
https://www.hobbyscoop.nl/

When you select "kaartweergave" a map is presented with a kind of RSSI
bar graph for each receiver. The UI speaks UK, NL and DE. You may need
to refresh the page after changing language.

Is your Dutch somewhat rusty? No problem, most people will switch to
something that you will recognize as English.

--
Wim, PA3DJS
Please delete abc before hitting the send button

[lordgnome]

There are a few Welsh ones I can make from here (Anglesey), some Irish
ones and one or two up North with a following wind. Frankly, I really
can't be assed with the complication of the CTSS guff though.
The only one I often check is the Criccieth one, since that responds to
a simple tone burst and is very handy for checking that everything is
working. Once a year or so, I might even catch someone using it!

Les.

[Brian Howie]

In message <nc43pe$v6i$1...@stc.eternal-september.org>, Stephen Thomas Cole
<use...@stephenthomascole.com> writes

The one with the widest coverage I can get is GB3LA

https://www.ukrepeater.net/my_repeater.php?callsign=gb3la

I can also get GB3SB

https://www.ukrepeater.net/my_repeater.php?callsign=gb3sb

There's a couple of others FF and DU

I might get further with a vertical antenna.

Brian


--
Brian Howie

[FranK Turner-Smith G3VKI]

"Wimpie" <wima...@tetech.nl> wrote in message
news:nc4dai$7mb$1...@gioia.aioe.org...

There's a common practice for RX called Diversity Reception. I'd never seen
it used for TX although there's no reason why it shouldn't reciprocate. I
live and learn.
--
;-)
.
73 de Frank Turner-Smith G3VKI - mine's a pint.
.
http://turner-smith.uk

[Wimpie]

El 13-Mar-16 a las 22:57, FranK Turner-Smith G3VKI escribió:

In aviation offset carrier systems were/are used. In a two-transmitter
system, two geographically separated transmitters get the same baseband
signal, but the carriers have an offset of 5 kHz.

When the receiver receives both signals, an at least 5 kHz beat
frequency is produced at the demodulator output. This beat frequency is
blocked by the audio low pass filter so only the base band signal will
reach the speaker.

In the PI2NOS system the transmitters are synchronized using GPS. This
is not only valid for the carrier, but audio latency and deviation is
also under strict control. You may experience some interference in
overlapping areas, but the advantage of a single frequency almost
nationwide repeater outweighs the disadvantages.

Besides the technical challenge, the amateur community itself has a
challenge: maintaining good Operating Practice.

[Paul Cummins]

In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
wrote:

> In aviation offset carrier systems were/are used. In a
> two-transmitter system, two geographically separated transmitters
> get the same baseband signal, but the carriers have an offset of 5
> kHz.
>
> When the receiver receives both signals, an at least 5 kHz beat
> frequency is produced at the demodulator output. This beat
> frequency is blocked by the audio low pass filter so only the base
> band signal will reach the speaker.

That could only work in an FM system - in AM (which is what's used in
Aviation) there would be sufficient heterodyne to lose both signals.

IMO, YMMV

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981
Please Help us dispose of unwanted virtual currency:
Bitcoin: 1LzAJBqzoaEudhsZ14W7YrdYSmLZ5m1seZ

[Paul Cummins]

In article <nc8pjl$c93$1...@gioia.aioe.org>, je...@ukra.com (Jeff) wrote:

> You are not correct that system is currently in use on the VHF air
> band with AM. London Centre on 121.5MHz is one example.

I will have to give this consideration, as I can;t see how that would
possibly work.

two AM signals, with each sideband being no more than 5kHz, 5kHz apart.
So the upper sideband of one signal will be interfering with the lower
sideband of the other, and the "outer" sidebands are separated by this
mush.

I will have to try listening in on 121.5 to see how well that works.

[Jerry Stuckle]

On 3/15/2016 5:15 AM, Paul Cummins wrote:
> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
> wrote:
>
>> In aviation offset carrier systems were/are used. In a
>> two-transmitter system, two geographically separated transmitters
>> get the same baseband signal, but the carriers have an offset of 5
>> kHz.
>>
>> When the receiver receives both signals, an at least 5 kHz beat
>> frequency is produced at the demodulator output. This beat
>> frequency is blocked by the audio low pass filter so only the base
>> band signal will reach the speaker.
>
> That could only work in an FM system - in AM (which is what's used in
> Aviation) there would be sufficient heterodyne to lose both signals.
>
> IMO, YMMV
>

FM's capture effect would mean only the stronger of the two came
through. AM would give you a heterodyne - which is exactly what you want.

--
==================
Remove the "x" from my email address
Jerry, AI0K
jstu...@attglobal.net
==================

[Brian Reay]

On 15/03/16 10:53, Jeff wrote:

> On 15/03/2016 09:15, Paul Cummins wrote:
>> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
>> wrote:
>>
>>> In aviation offset carrier systems were/are used. In a
>>> two-transmitter system, two geographically separated transmitters
>>> get the same baseband signal, but the carriers have an offset of 5
>>> kHz.
>>>
>>> When the receiver receives both signals, an at least 5 kHz beat
>>> frequency is produced at the demodulator output. This beat
>>> frequency is blocked by the audio low pass filter so only the base
>>> band signal will reach the speaker.
>>
>> That could only work in an FM system - in AM (which is what's used in
>> Aviation) there would be sufficient heterodyne to lose both signals.
>>
>> IMO, YMMV
>>
>

> You are not correct that system is currently in use on the VHF air band
> with AM. London Centre on 121.5MHz is one example.
>

> Jeff

There was also the Plessey system, as I recall it was called 'Ground
Sat'. I believe they sold it into some overseas markets but I'm not sure
the UK bought it- budgets were 'tight' at the time and the UK were
already in the early stages of a long term upgrade. That, of course,
went belly up and the contract was cancelled and put out for re-tender.
(I'm not suggesting Plessey or Ground Sat were responsible for the
failure of the first contract, it was a series of issues which led to
the demise- not least unclear requirements and lots of 'can we just haves'.

When Plessey were subsumed into whoever (I can't recall who got the
radio bit, I think Thales eventually as I was offered a job with them
some years later in the comms area), I don't know if Ground Sat
continued, perhaps under another name.

Ground Sat was a single frequency, ground based, repeater. I can't
recall exactly how it worked but I'm sure a basic block diagram has
published in various magazines, including RadCom I think. This must have
been in the early 80s at a guess. I believe one of the leading lights in
its development was an amateur, who also produced a number of designs
based on the Plessey SL series of ICs which were common in the late 70s
early 80s. I used some of them in various homebrew projects, and my 3rd
year Uni project.

Ground Sat operated between about 30 and 70 MHz if my memory serves. I'm
pretty sure it was FM and used two antennas. Obviously no cavities were
required.

[lordgnome]

On 15/03/2016 13:49, Jerry Stuckle wrote:
> On 3/15/2016 5:15 AM, Paul Cummins wrote:
>> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
>> wrote:
>>
>>> In aviation offset carrier systems were/are used. In a
>>> two-transmitter system, two geographically separated transmitters
>>> get the same baseband signal, but the carriers have an offset of 5
>>> kHz.
>>>
>>> When the receiver receives both signals, an at least 5 kHz beat
>>> frequency is produced at the demodulator output. This beat
>>> frequency is blocked by the audio low pass filter so only the base
>>> band signal will reach the speaker.
>>
>> That could only work in an FM system - in AM (which is what's used in
>> Aviation) there would be sufficient heterodyne to lose both signals.
>>
>> IMO, YMMV
>>
>
> FM's capture effect would mean only the stronger of the two came
> through. AM would give you a heterodyne - which is exactly what you want.
>

On the subject of commercial air-comms, I sometimes listen to what comes
& goes over my manor. I have to say that some of the ground control
signals are appalling. Muffled transmissions and operators who gabble -
Am. radio might be considered less important by far, but MOST signals
and clarity of speech from amateur operators would put some of those
chaps to shame.

Les.

[Wimpie]

El 15-Mar-16 a las 10:15, Paul Cummins escribió:

> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
> wrote:
>
>> In aviation offset carrier systems were/are used. In a
>> two-transmitter system, two geographically separated transmitters
>> get the same baseband signal, but the carriers have an offset of 5
>> kHz.
>>
>> When the receiver receives both signals, an at least 5 kHz beat
>> frequency is produced at the demodulator output. This beat
>> frequency is blocked by the audio low pass filter so only the base
>> band signal will reach the speaker.
>
> That could only work in an FM system - in AM (which is what's used in
> Aviation) there would be sufficient heterodyne to lose both signals.
>
> IMO, YMMV
>

It does work in AM systems, but with some limitations. To be honest, I
don't even know whether it works accaptable with FM, when signals have
same strength.

With a 4 carrier AM system in a 25 kHz channel, 5 kHz offset, there is
some overlap in side bands introducing "new" base band components (due
to frequency instability and not to forget doppler shift). As expected,
this reduces intelligibility, but it is usable.

When less carriers are used, the offset can be more, and will be more to
avoid reduction of intelligibility (who "invented" that word?).

[Ian Jackson]

In message <nc99pj$m48$1...@dont-email.me>, lordgnome <l...@nospam.null>
writes

Indeed, it does seem to be de rigueur that all ATC communications be
carried out at much faster than the rate of normal speech, and with the
mouth usually far too close to the microphone. Surprisingly, it is
generally successful! I can only assume that there are good reasons for
this way of doing things, and the those charged with using the radios
are specially trained in the 'correct' technique.
--
Ian

[Jerry Stuckle]

Les,

I don't know what it's like there, but I've never had any problem with
ground control (or any other ATC transmissions) here. No muffled
transmissions.

Yes, sometimes when it's pretty slow you can gab with them some. But
every time they've been clear and very professional.

[Jerry Stuckle]

Yes, we have the problem with two fast speech here sometimes, also. The
tower might give orders such as "Cessna xxx cleared for takeoff. Climb
to four zero zero feet turn left to zero three zero degrees. Climb and
maintain one eight zero zero feet." All in about two seconds. You need
to right it down and repeat it back to ensure you got it correct. But
they also need to do that when they're busy; at those times there is no
end to the traffic on the tower channel.

But yes, there is a specific pattern to the communications, and my CW
practice has helped me right quickly and abbreviate where necessary.

And my flight instructors never have figured out how I can decode the CW
id for the VOR stations without referring to the chart! :)

[Brian Reay]

On 15/03/16 13:49, Jerry Stuckle wrote:
> On 3/15/2016 5:15 AM, Paul Cummins wrote:
>> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
>> wrote:
>>
>>> In aviation offset carrier systems were/are used. In a
>>> two-transmitter system, two geographically separated transmitters
>>> get the same baseband signal, but the carriers have an offset of 5
>>> kHz.
>>>
>>> When the receiver receives both signals, an at least 5 kHz beat
>>> frequency is produced at the demodulator output. This beat
>>> frequency is blocked by the audio low pass filter so only the base
>>> band signal will reach the speaker.
>>
>> That could only work in an FM system - in AM (which is what's used in
>> Aviation) there would be sufficient heterodyne to lose both signals.
>>
>> IMO, YMMV
>>
>
> FM's capture effect would mean only the stronger of the two came
> through. AM would give you a heterodyne - which is exactly what you want.
>

Capture effect is limited with low deviation systems.

Predicting when it will 'work' is complicated, it depends on several
things, including deviation and relative signal strength. But, as a
general rule, low dev. systems benefit less from it.

[Brian Reay]

On 15/03/16 16:24, Wimpie wrote:
> El 15-Mar-16 a las 10:15, Paul Cummins escribió:
>> In article <nc6aor$o8l$1...@gioia.aioe.org>, wima...@tetech.nl (Wimpie)
>> wrote:
>>
>>> In aviation offset carrier systems were/are used. In a
>>> two-transmitter system, two geographically separated transmitters
>>> get the same baseband signal, but the carriers have an offset of 5
>>> kHz.
>>>
>>> When the receiver receives both signals, an at least 5 kHz beat
>>> frequency is produced at the demodulator output. This beat
>>> frequency is blocked by the audio low pass filter so only the base
>>> band signal will reach the speaker.
>>
>> That could only work in an FM system - in AM (which is what's used in
>> Aviation) there would be sufficient heterodyne to lose both signals.
>>
>> IMO, YMMV
>>
>
> It does work in AM systems, but with some limitations. To be honest, I
> don't even know whether it works accaptable with FM, when signals have
> same strength.
>
> With a 4 carrier AM system in a 25 kHz channel, 5 kHz offset, there is
> some overlap in side bands introducing "new" base band components (due
> to frequency instability and not to forget doppler shift). As expected,
> this reduces intelligibility, but it is usable.

Presumably the reason they 'lock' the frequency via GPS, as you
mentioned I believe, is to minimise stability issues. I've not done any
calculations, perhaps you have, but is doppler that significant at the
speeds concerned? Obviously it is with satellite passes but the speed of
those is significantly higher.

[Wimpie]

El 15-Mar-16 a las 21:31, Brian Reay escribió:

You are right, nowadays stability is not an issue, even the amateur
repeaters use GPS synchronized oscillators.

At VHF doppler (one TX behind you, one TX in front of you), is limited
to 200 Hz (900 km/h), but at UHF it can be around 600 Hz for 900 km/h.
For aircraft flying above Mach 1 the situation is different (worse).

We also have an almost nationwide 2m repeater (PI3UTR, 145.575 MHz out,
-0.6 MHz shift). I don't know the current situation, but they
experimented with about 10 Hz offset between TX carriers. I could notice
that. Two signals arrived at my location. When turning my 2 m sector
antenna I could eliminate (or enhance) the annoying effect.

Technically both PI2NOS and PI3UTR are a real succes, and UK based Radio
Amateurs worked them already over the air.

It is now becoming a social experiment..., as some Neandertaler type of
person (or even worse single-celled) is able to jam the system.

--
Wim, PA3DJS
In case of PM, please instruct your racing pigeon to remove abc.

[Jerry Stuckle]

Yes and no. FM receivers run their last IF before the detector at full
saturation and only the strongest signal comes through. And generally,
the low deviation systems benefit more than the wider deviation.

Our commercial FM radio band here runs +/- 75kHz deviation (probably
similar to what's over there, but I don't know). And when you get at
the boundary of overlapping stations, you can hear them both.

We have one place near me where this occurs. A low power station
operates on the same frequency as one of the local stations. When you
get close enough, they both try to come through. Unlike the local
repeaters with +/- 5 kHz deviation where it's almost impossible to hear
this effect.

[Jerry Stuckle]

On 3/16/2016 4:23 AM, Brian Reay wrote:

> Can amateurs transmit from aircraft in P land? Our licence doesn't allow
> it?
>

Are you sure? Many countries allow operating from planes, but only with
the pilot's permission (virtually impossible to get on commercial
airliners). I've had a lot of fun on 2M simplex - even at 3,000 ft
above ground a 1W ht can have a 150+ mile range.

It does make it easy to get permission when you're the pilot! :)

[Brian Reay]

On 16/03/16 12:52, Jeff wrote:
>
>>> You are right, nowadays stability is not an issue, even the amateur
>>> repeaters use GPS synchronized oscillators.
>>>
>>> At VHF doppler (one TX behind you, one TX in front of you), is limited
>>> to 200 Hz (900 km/h), but at UHF it can be around 600 Hz for 900 km/h.
>>> For aircraft flying above Mach 1 the situation is different (worse).
>>

>> Can amateurs transmit from aircraft in P land? Our licence doesn't allow
>> it?
>>

>> If you can't, we only need to consider the 200Hz figure, as air band
>> is VHF
>> (other than mil. air band).
>>
>
> If you are not considering /AM then the figure is a lot less than 200Hz,
> I can't think of a car that goes at 900 km/h!!!!!
>
> Jeff

Indeed Jeff, which is why I asked about /AM in P land. Plus, of course,
even light aircraft (the type most PPLs fly) aren't that rapid. I forget
the recommended cruising speed of the Robin DR400 but I think is was
about 65kts.Even allowing for a tail wind, getting to 900km/h would be
'adventurous' ;-) but I'm sure Wimpie wasn't suggesting that could
happen. However, mil. jets do use the VHF aviation band so Wimpie's
point is valid.

Perhaps it would be better to come at from the other direction (no pun
intended), and ask what difference/error in frequency due to Doppler
shift is the the performance degraded to a point defined as being out of
spec. Then, use that to calculate the speed (or speeds, they will vary
slighlty across the band) the vehicle can be travelling.

I suspect the tolerable error is small as trouble has been taken to lock
the units frequency together but there may be another reason for that
and I confess I'm not with the details of the system.

[Jerry Stuckle]

Most single engine light planes (not light sport category) cruise in the
100-140 kt range, with a few above or below that. Turboprops may get up
to 200 kts. Most can't afford multi-engine planes as a hobby (not that
single engines are cheap).

And at those speeds, Doppler shift would be less than error margins
unless you had some expensive, lab grade equipment.

GPS detects location by the difference between time signals received
from the satellites, and velocity by the differences between locations.
AFAIK, it doesn't use Doppler shift at all.

Of course, radar (both ground and airborne) does use Doppler shift to
determine relative velocity. But AFAIK, it's the only place Doppler is
used for aircraft.

[Brian Reay]

Oh, quicker than I thought. Perhaps I was thinking of the optimal climb
speed, it is some decades since I let my qualification lapse. I have
thought of renewing it but I can't see my having the time to make it
worthwhile. Plus my stroke may be an issue.

>
> And at those speeds, Doppler shift would be less than error margins
> unless you had some expensive, lab grade equipment.
>
> GPS detects location by the difference between time signals received
> from the satellites, and velocity by the differences between locations.
> AFAIK, it doesn't use Doppler shift at all.

Trigulation. But we weren't discussing Doppler on the GPS signal, Wimpie
was referring to Doppler shift on the voice channel- hence the
difference at UHF.

[Jerry Stuckle]

Which optimal climb speed? There's best angle of climb (Vx), where you
get the maximum altitude for the minimum horizontal distance. Then
there's best rate of climb (Vy), where you get the maximum altitude for
a time period. Vx is somewhat slower than Vy, but in small planes
somewhere around 65-75 kts would be about right.

>
>>
>> And at those speeds, Doppler shift would be less than error margins
>> unless you had some expensive, lab grade equipment.
>>
>> GPS detects location by the difference between time signals received
>> from the satellites, and velocity by the differences between locations.
>> AFAIK, it doesn't use Doppler shift at all.
>
> Trigulation. But we weren't discussing Doppler on the GPS signal, Wimpie
> was referring to Doppler shift on the voice channel- hence the
> difference at UHF.
>

Yes, I was just pointing out that even GPS doesn't use Doppler shift.
And Doppler shift on a VHF channel (118-136 MHz) is virtually
unmeasurable unless you have a very stable reference such as a GPS
signal and are using lab quality equipment.

[Wimpie]

El 16-Mar-16 a las 09:23, Brian Reay escribió:

>
> Can amateurs transmit from aircraft in P land? Our licence doesn't allow
> it?
>
> If you can't, we only need to consider the 200Hz figure, as air band is VHF
> (other than mil. air band).

For doppler (200, 600 Hz) on Carrier Offset Systems I was referring to
VHF/UHF aviation AM transmitters only.

/AM operation is allowed, of course only after permission from the pilot.

>
> We have a few of those, although the problem isn't as bad as it was in the
> late 1970s. It is years since I heard a jammer on a repeater. We have on
> localish repeater known for poor operating. Many are under used.

Here also many repeaters are under-used, but the two nationwide
repeaters are very busy. You can use them with a handheld with a simple
antenna from over a wide area. I have a feeling that 70 cm repeater use
in PA country is increasing due to cheap equipment and maybe because of
PI2NOS.

Several ON amateurs use the nationwide repeaters also. There is even a
receiver on Belgium territory (South of Antwerp).

operating practice
When some people are better in talking then listening, communication
efficiency drops significantly. The probability for such an event
increases rapidly with nationwide repeaters.

[Jerry Stuckle]

On 3/17/2016 4:58 AM, Jeff wrote:
>>> Can amateurs transmit from aircraft in P land? Our licence doesn't allow
>>> it?
>>>
>>
>> Are you sure? Many countries allow operating from planes, but only with
>> the pilot's permission (virtually impossible to get on commercial
>> airliners). I've had a lot of fun on 2M simplex - even at 3,000 ft
>> above ground a 1W ht can have a 150+ mile range.
>>
>> It does make it easy to get permission when you're the pilot! :)
>>
>

> Holland is about the only country in Europe that allows aeronautical
> mobile.
>
> Jeff

Jeff,

That's interesting - and too bad. I've had a lot of fun on 2M simplex
aeronautical mobile. Is there any reason for it that you know of?

[Jerry Stuckle]

On 3/17/2016 4:12 AM, Brian Reay wrote:

> All I recall is 65kts, it is about 30 years since my qualifications lapsed
> so I confess I've not needed
> to worry about flying small aircraft for some time. I was fortunate that my
> employer funded my training
> but the scheme them changed and they stopped funding the time needed to
> stay current. That, plus other pressures on my time, including traveling to
> the US a lot, and I decided to let it lapse.

>
>
>>>>
>>>> And at those speeds, Doppler shift would be less than error margins
>>>> unless you had some expensive, lab grade equipment.
>>>>
>>>> GPS detects location by the difference between time signals received
>>>> from the satellites, and velocity by the differences between locations.
>>>> AFAIK, it doesn't use Doppler shift at all.
>>>
>>> Trigulation. But we weren't discussing Doppler on the GPS signal, Wimpie
>>> was referring to Doppler shift on the voice channel- hence the
>>> difference at UHF.
>>>
>>
>> Yes, I was just pointing out that even GPS doesn't use Doppler shift.
>> And Doppler shift on a VHF channel (118-136 MHz) is virtually
>> unmeasurable unless you have a very stable reference such as a GPS
>> signal and are using lab quality equipment.
>>
>

> Perhaps it would help if I recapped the path of discussion:
>
> Wimpie mentioned the voice Channel frequencies were all GPS locked and
> mentioned Doppler. I commented I thought the Doppler would be low, Wimpie
> calculated 200Hz at VHF for civil aircraft (he didn't mention speed). I
> suggested perhaps it would be better to approach it the other way, what
> shift was a problem, then work out the corresponding speed.
>
> I think you joined in the latter part and perhaps miss-understood the
> aspects we were discussing, rather than how things like GPS etc work
>
>

No, I understood the thread. Just pointing out how small the Doppler
shift is, and that it's not used in aeronautics - for voice channels or
anything else (other than radar). The amount of shift is way too low to
be measurable unless you have lab equipment that is also GPS locked.

--
==================
Remove the "x" from my email address

Jerry Stuckle
jstu...@attglobal.net
==================

[Brian Reay]

Wimpie wasn't suggesting it was used either on GPS or the voice channel.
He hinted that there were issues with frequency stability (hence the GPS
locking) and Doppler. I'm not sure of the nature of the problems, my
first reaction was the Doppler would be small (and Wimpie kindly
calculated 200Hz, I've not checked but I'm not claiming he is wrong).

At the moment, I'm happy to accept Wimpie's figure, although I have
suggested coming at it the other way, ie what shift can be tolerated and
calculate the speed which that corresponds to.

Unfortunately, I don't know enough about the system to know what shift
can be tolerated. I don't know if Wimpie does.

I was merely trying to ensure you understood that Wimpie and I were not
discussing USING Doppler, more that Doppler was an issue (problem) on
the voice channel and what Doppler shift could be tolerated.

[Brian Reay]

On 17/03/16 14:16, Jerry Stuckle wrote:
> On 3/17/2016 4:58 AM, Jeff wrote:
>>>> Can amateurs transmit from aircraft in P land? Our licence doesn't allow
>>>> it?
>>>>
>>>
>>> Are you sure? Many countries allow operating from planes, but only with
>>> the pilot's permission (virtually impossible to get on commercial
>>> airliners). I've had a lot of fun on 2M simplex - even at 3,000 ft
>>> above ground a 1W ht can have a 150+ mile range.
>>>
>>> It does make it easy to get permission when you're the pilot! :)
>>>
>>
>> Holland is about the only country in Europe that allows aeronautical
>> mobile.
>>
>> Jeff
>
> Jeff,
>
> That's interesting - and too bad. I've had a lot of fun on 2M simplex
> aeronautical mobile. Is there any reason for it that you know of?
>

Well, in the UK at least, our CAA (the equivalent of your FAA) are just
very 'tight'.

I believe attempts have been made in the past to get changes made but
they have always met a stone wall.

Also, hobby flying is much less common here, it is very expensive even
to keep your licence current, let alone learn to fly. I would never have
considered it had my company not had a scheme which paid for it and,
initially, paid for hours to keep your licence current and add
'ratings'. The latter part of the scheme was cut just as I complete my
training etc. and I would have needed to fund the hours to keep my
qualifications current. To be blunt, we had other things at the time to
spend the money on which were far more important- and that is besides
the issue of time etc. I believe the whole scheme has since been cut.
I certainly know a lot of people did as I did and simply let things
lapse. I've since thought of perhaps going back to it but pressure of
time etc. is another factor. I like hobbies where I can decide at the
spur of the moment, more or less, I fancy going/doing some xyz today,
you can't do that when you need to book an aircraft, the weather may be
against you, etc. etc. Even when I was training it was a bit of a pain,
my licence qualifying cross country was cancelled a couple of times
before I took off due to the airfield being fogged in. Eventually I got
it done. It is bad enough going fishing at short notice and phoning
around to find somewhere with some bait available (you normally have to
preorder here).

As a result, while there are amateurs with licences, there aren't many
so the demand for /AM isn't high in the UK.

Interest has increased due to things like the various balloon projects,
which took some time to be accepted by the CAA, but they use 'licence
free' equipment which works in the 70cm band but was designed for things
like car key fobs, data transmission, and the like. Amateurs are often
involved but anyone can do it, provided they get the balloon permit from
the CAA. The RF side doesn't need a licence.

As an aside, we've had some issues with microlight (and similar) users
using the lower end of 2m rather than obtaining equipment etc. for the
VHF aircraft band. OCFOM (our FCC) having been overly active in dealing
with the problem. I assume the availability of cheap radios has fueled
this problem. They also operate around 143MHz, I forget who that is
allocated to here.

[Jerry Stuckle]

It's not a problem, even at supersonic flight speeds. The shift is
still well within the channel bandwidth.

It does become apparent at speeds such as satellite orbits. But we're
talking thousands of mph.

> At the moment, I'm happy to accept Wimpie's figure, although I have
> suggested coming at it the other way, ie what shift can be tolerated and
> calculate the speed which that corresponds to.
>

Yes, and my point was you could only do that if you had lab-grade
equipment that was also GPS locked on the plane. It's the only
equipment which would have the necessary accuracy.

> Unfortunately, I don't know enough about the system to know what shift
> can be tolerated. I don't know if Wimpie does.
>

In the U.S., voice channels have 25kHz spacing. Europe uses 8.33kHz
spacing. With maximum audio frequencies limited to approximately 3kHz,
you have 2.33kHz spacing between channels - much more than any Doppler
shift caused by aircraft speeds. U.S. is even less critical.

> I was merely trying to ensure you understood that Wimpie and I were not
> discussing USING Doppler, more that Doppler was an issue (problem) on
> the voice channel and what Doppler shift could be tolerated.
>

Yes, I understand that - but I was also commenting on the notes about
measuring the Doppler shift and using that to calculate speed.

It's not even a problem with SSB on the HF bands that aircraft use for
transoceanic routes, where the frequency shift is even more noticeable
than on AM. But then of course Doppler shift on HF is less than that on
VHF.

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Jerry Stuckle]

On 3/17/2016 12:39 PM, Jeff wrote:
>
>>
>> Jeff,
>>
>> That's interesting - and too bad. I've had a lot of fun on 2M simplex
>> aeronautical mobile. Is there any reason for it that you know of?
>>
>

> No specific reason, just the regulators' (inc the aviation regulators)
> paranoia over interference, and distraction of the pilot.
>
> Jeff

Over here, it's been more concern about interference to the aircraft
instruments. But that started way back in the 30's or 40's (long before
my time), and instruments have improved since then. But the paranoia
still exists.

That concern is also why you can't run electronics during commercial
flights' takeoffs/landings and are still limited to what electronics you
can use while in flight (no radios, for instance - even receivers,
because they have local oscillators). A shame because my HT also has
aircraft band and I enjoy listening to the conversations while flying.
But if the pilot gives his/her OK, you can.

A couple of years ago the FAA studied as to whether to allow cell phones
on planes while in flight or not. There was a huge outcry about the
proposal - interestingly enough not from the airlines, but from the
passengers. People don't want to be cooped up in an aluminum tube with
175 people trying to all talk on their phones at the same time.

[Jerry Stuckle]

It's not cheap here, either. When I first got my license about 40 years
ago, I was renting for $20/hr. Nowadays I'm looking at $140/hr. (more
at the closer airports). Plus it's a PITA to get in and out of the
Washington, DC airports due to security restrictions. My other choice
is to drive 30 miles each way where I don't have to fight the
restrictions and can get a cheaper rental. As a result, I don't get
much A/M in nowadays. Not nearly as much as I would like, for sure.

I always wanted to try a VHF contest A/M. That would be a real hoot!

[Brian Reay]

I must have missed that suggestion. Who made it?

[Jerry Stuckle]

Actually, you did, indirectly:

"Perhaps it would be better to come at from the other direction (no pun
intended), and ask what difference/error in frequency due to Doppler
shift is the the performance degraded to a point defined as being out of
spec. Then, use that to calculate the speed (or speeds, they will vary

slightly across the band) the vehicle can be traveling. "

By calculating speed where performance is degraded, you are indirectly
calculating the speed based on the Doppler shift.

[Brian Reay]

On 17/03/16 22:24, Huge wrote:
> On 2016-03-17, Brian Reay <no...@m.com> wrote:
>
> [177 lines snipped]

>
>>
>> I must have missed that suggestion. Who made it?
>

> Could I ask you gentlemen to snip the irrelevant parts of the thread history,
> please?
>
>

Good point most of the time Huge. However, on this occasion, there seems
to have been some confusion, so perhaps it wasn't a good idea.

I suspect the thread has run its course now, or at least the Doppler
strand, unless Wimpie can tell us what shift is 'acceptable'. In
fairness, I've no idea what the limit is, not being familiar with the
system.

The linked repeater system in PA land sounds interesting. I will have to
remember and try it when we visit on one of our 'jollies' to Europe.

[Jeefaw K. Effkay]

On Sunday, March 13, 2016 at 4:42:10 PM UTC, Stephen Thomas Cole wrote:
> I've been mulling for a while that it'd be nice to have a QSO with some of
> the ukra/ukram users, and a very nice chat just now with a former ukra
> poster, Andy G0FTD, on GB3RE suggests that repeaters might be a good place
> to start!
>
> I'm not in a great spot at this QTH for VHF/UHF, there's a lot of geography
> in my way in most directions. But I can access the following:
>
> GB3IK
> GB3KN
> GB3DA
> GB3KI on 2m
>
> & GB3RE on 70cm.
>
> Can anybody else open any of these up?
>
> In my car, at the top of the valley here, I can open up many of the London
> repeaters, as well as Ipswich and Norfolk (with a good wind behind me) and
> likely more. Would be great if there's anyone who can get in to the
> repeaters I can work from home, though!

I thought I'd have a play tonight. I was a bit surprised at the results, as conditions seem fairly flat on 2 and 70:

I can get into GB3DA, bit it's co-channel with GB3SN, which is a bit stronger.

I can also get into GB3CF in Leicester.

The real surprise is that I can also access the 2 Norwich repeaters from here, both at 185km distant. GB3NR on 70cm and GB3NB on 2m. Unfortunately both are co-channel with much stronger repeaters, GB3BN and GB3MH respectively.

[Wimpie]

Some recapitulation.

Aviation
In AM aviation, single channel (25 kHz) operation is possible with
several transmitters having an offset. AM avaition uses the trick that
when the offset is large enough, carrier beat frequency is well above
the 3 kHz audio band and is blocked by the audio band pass filter.

The goal of the system is that you never receive two transmitters within
a channel that are on the same frequency. With a two carrier system (+
7.3 kHz and - 7.3 kHz offset), audio quality is perfect as also the side
bands do not generate products that fall within the audio band.

In a 4 carrier system -7.5, -2.5 + 2.5 and 7.5 kHz offset are used. So
the carrier beat is minimum 5 kHz, but the side bands generate in band
audio products.

In another posting a gave a 900 km/h example when one tranmitter is
ahead, one is behind. In that case you have twice the doppler shift. For
VHF air band this will be 200 Hz, but for UHF this will be 600 Hz. As in
the pre-GPS era frequency stability was a concern, carrier beat may be
close to the audio band because of both frequency stability and doppler
shift.

Doppler shift [Hz] = (carrier frequency [Hz])*(velocity [m/s])/C0

C0 = 3e8 m/s (speed of light).

During frequency planning, (for example) a 4 carrier system, planning
would be such that you will not hear two adjacent frequencies with same
strength as in that case intelligibility is significantly reduced. I ran
some simulation for 5 kHz offset and it is really full of "new"
products. 10 kHz offset gives clean audio output.

Amateur
The RX/TX coversity amateur systems in PA country:

PI2NON (430.275 MHz, north-east part of PA), first simple implementation
around 2006/7
PI3UTR (145.575 MHz, almost nation wide), can be reached from UK
PI2NOS (430.125 MHz, almost nation wide), can be reached from UK


Frequencies are slaved to GPS (GPSDO). So on average frequency is the
same for all transmitters in one system, but of course there will be
some phase jitter. Modulation is delayed such that in the overlapping
areas there is minimum timing error (in the tens of us). RX and TX are
coupled via the internet or hamnet.

Each audio packet that is sent to all transmitters has a time stamp
laying in the future. It is stored and transmitter at GPS derived time.
Of course, group delay and devation of the transmitters must be matched
as good as possible.

As far as I know, they do not use carrier offset (anymore). You will
have some reduction in intelligibility when you are in an area where you
receive signals from two transmitters. I had distortion in reception on
the PI3UTR system some years ago, but with reorienting the antenna I
could avoid it. They changed the system somewhat (power and/or antenne
heigth), so I don't have problems anymore.

In a mobile environment, just live with the interference until one of
the transmitters is dominant.

With FM you don't get a nice beat frequency, especially when one signal
is dominant. Besides that, doppler shift is low, even at UHF. Think of
80 Hz for the transmitter ahead and behind situation (430 MHz, 100 km/h).

When you listen to PI2NOS (430.125), you will seldom hear discussion on
distortion due to reception of two transmitters, so the system does its
job.

Hopefully this demystifies the doppler issue.

[Paul Cummins]

In article <ncheb6$vhu$1...@dont-email.me>, lau...@home.invalid (Laurie)
wrote:

> It's know as Climax operation.

I'm still not seeing it - perhaps I need to review AM theory :-)

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981
Please Help us dispose of unwanted virtual currency:
Bitcoin: 1LzAJBqzoaEudhsZ14W7YrdYSmLZ5m1seZ

[Jerry Stuckle]

Originator: webs...@chiark.greenend.org.uk ([212.13.197.229])
Xref: goblin2 uk.radio.amateur.moderated:1143

On 3/18/2016 4:14 AM, Brian Reay wrote:

> Jerry Stuckle <jstu...@attglobal.net> wrote:

>> On 3/17/2016 4:04 PM, Brian Reay wrote:

>>> On 17/03/16 18:13, Jerry Stuckle wrote:

>>>>

>>>> Yes, I understand that - but I was also commenting on the notes about

>>>> measuring the Doppler shift and using that to calculate speed.

>>>>

>>>

>>> I must have missed that suggestion. Who made it?

>>>

>>>

>>

>> Actually, you did, indirectly:

>>

>> "Perhaps it would be better to come at from the other direction (no pun

>> intended), and ask what difference/error in frequency due to Doppler

>> shift is the the performance degraded to a point defined as being out of

>> spec. Then, use that to calculate the speed (or speeds, they will vary

>> slightly across the band) the vehicle can be traveling. "

>>

>> By calculating speed where performance is degraded, you are indirectly

>> calculating the speed based on the Doppler shift.

>>

>

>

>

> Ah, I thought so.

>

> Not quite.

>

> Wimpie suggested that the Doppler caused an issue.

>

> He calculated a 'typical' Doppler shift, at VHF- which I've not checked but

> don't dispute.

>

> I suggested perhaps another way to approach the problem was to decide what

> Doppler you could tolerate and then calculate the speed it corresponds to.

> That would give you the limit of the system. No lab grade equipment needed

> to measure the Doppler.

>

> I'm not familiar with the system and don't know why such small changes in

> frequency are an issue. I was hoping Wimpie would explain and perhaps know

> the limiting value of shift the system can tolerate and still yield

> acceptable performance.

>

> So, I wasn't measuring speed, I was finding the limits of the system. The

> latter is done once, as an analysis exercise, not while the system is in

> service.

>

>



BTW - I checked the Doppler shift at 120 mph for aircraft frequencies -

it's about 25hz. Even at Mach 1 it would be less than 125hz. Not

enough to worry about.

[Jerry Stuckle]

On 3/20/2016 1:40 PM, Jeff wrote:
>
>>
>> BTW - I checked the Doppler shift at 120 mph for aircraft frequencies -
>>
>> it's about 25hz. Even at Mach 1 it would be less than 125hz. Not
>>
>> enough to worry about.
>>
>

> .. and that is only when coming either straight at you or away from you.
> Add the Cos theta term to the equitation for other angles.
>
> Jeff
>

I was just looking at worst case. But you are quite correct.

[Tim Hague]

A few years ago I was contracted to carry out some field measurements inside a 747 and an Airbus A310. We simulated cellphone traffic at various points inside the aircraft and took field measurements in the cockpit, avionics bay, upper cabin and the luggage bay. It was interesting to see from the rear of the plane what little loss there was due to the waveguide effects of the cabin...the field measured inside the avionics suite from a 2W transmitter in the rear of the plane at 900MHz exceeded the clearance level in place at the time.
Copies of our report can be found in the CAA archives.
Since those days of course the test levels laid down in DO160 have increased such that it's unlikely a cell phone would cause any problems...

[Jerry Stuckle]

That's interesting, Tim. I never considered the waveguide effect of the
aluminum tube, but it makes sense.

I remember a report (I don't know how valid it was) back in the late
1980's when 80486 laptops first came out that a pilot in a commercial
airliner was having instrument problems. There was a guy in First Class
running a 486-based laptop; as soon as he put it away, the instrument
problems stopped.

As I said - I can't attest to the veracity of the report, but I found it
interesting. And with airplane instrumentation at the time, I wouldn't
be surprised.

However, I also agree with you aircraft electronics has improved greatly
in the last 25 years or so. A couple of years ago the FAA over here
proposed allowing cell phone usage in commercial airlines when over
10,000 ft. The public outcry was tremendous, and most (all?) of the
major airlines indicated they didn't care what the FAA said - cell phone
usage would not be allowed unless parked at the gate. The proposal was
quietly dropped by the FAA.

I've only used a 144/440Mhz HT on light planes and seen no problems with
instrumentation. But maybe I've been lucky.

[Roger Hayter]

Brian Reay <no...@m.com> wrote:

> I believe mobile phones reduce power to that required to reach the nearest
> 'cell'. One solution would perhaps be to have a box on the aircraft, with a
> low power tx/Rx inside and an external antenna with a more powerful tx,
> rather like the (illegal) boosters sold fQor use in poor coverage areas.
> That would reduce the RF in the aircraft with the fuselage providing some
> screening.

That is indeed what they have done in experiments to allow moblie phones
on planes. It also avoids the problem of many cells on the ground
having to deal with weak rapidly changing signals from the plane, and
there being no service over oceans.


>
> The idea of people using phones on aircraft as they do on trains doesn't
> really appeal. My days of thinking that a flight is fun are long past and
> the idea of my peace being disturbed as I try to read or sleep, doesn't
> appeal.

Quite agree. If they do do it, they should ban voice except for short
periods. That still leaves SMS and email comms though.



--

Roger Hayter

[Tim Hague]

Another solution that could be used is a leaky feeder system, I put the first system in the Dartford Tunnel , worked really well..

But as a regular passenger on aircraft I really would prefer if they were phone free.., just a personal opinion of course...

73. Tim M0AFJ

[Jerry Stuckle]

On 3/23/2016 3:37 AM, Jeff wrote:
>
>> I've only used a 144/440Mhz HT on light planes and seen no problems with
>> instrumentation. But maybe I've been lucky.
>>
>

> Just to highlight what can happen with unregulated equipment, I have a
> scanner that when tuned to some frequencies in the 6m band will block a
> GPS receiver at at distance of about 20'.
>
> That is due to the fact that it has a high IF and the LO is consequently
> at quite a high frequency; the level of LO and harmonics that leak out
> of the antenna is high enough for one of the harmonics to cause problems
> to the relatively weak GPS signals.
>
> Jeff

That fact it happens isn't surprising, although 20' is. I would have
expected maybe 5-6' max.

We had a company called LightSquared which tried to implement a 4G
system in a band next to the GPS band. This band is licensed for weak
signal satellite communications, but LightSquared wanted to use it for
high power land-based. Unfortunately, their signal wiped out GPS in
aircraft over a wide range around their test site. They tried to fix
the problem and even sued GPS manufacturers for having too wide front
ends.

The FCC was finally forced to bar LightSquared from operating their
proposed network when the NTIA (the organization that coordinates
governmental and military spectrum usage) said there was no way to
mitigate the interference. And since the military needs GPS...

[Jim GM4DHJ ...]

"Tim Hague" <m0...@yahoo.co.uk> wrote in message
news:e8b8c693-c72a-4b63...@googlegroups.com...

cellphones work in the clyde tunnel.... and I once worked somebody on 80m
for some of the way through......

[Wimpie]

El 13-Mar-16 a las 17:16, Stephen Thomas Cole escribió:

> I've been mulling for a while that it'd be nice to have a QSO with some of
> the ukra/ukram users, and a very nice chat just now with a former ukra
> poster, Andy G0FTD, on GB3RE suggests that repeaters might be a good place
> to start!
>
> I'm not in a great spot at this QTH for VHF/UHF, there's a lot of geography
> in my way in most directions. But I can access the following:
>
> GB3IK
> GB3KN
> GB3DA
> GB3KI on 2m
>
> & GB3RE on 70cm.
>
> Can anybody else open any of these up?
>
> In my car, at the top of the valley here, I can open up many of the London
> repeaters, as well as Ipswich and Norfolk (with a good wind behind me) and
> likely more. Would be great if there's anyone who can get in to the
> repeaters I can work from home, though!
>

Yesterday evening/night (20 April 2016) there were good tropo conditions.

Several UK stations worked our nationwide PI2NOS repeater (430.125, +1.6
MHz shift) directly. Not just coastal stations, but also stations say
150 km inland.

via www.hobbyscoop.nl (and then hit "kaartweergave"), one could see the
propagation of the tropo conditions moving towards the east.

Several NL-stations could hear the UK stations directly.

[Wimpie]

El 21-Apr-16 a las 18:48, Wimpie escribió:

There is good tropo now. M1COV (Syd) is currently talking with Dutch
stations. He opens over 7 receivers now (from Belgium (Antwerpen) up to
Leeuwarden and Groningen).

[Stephen Thomas Cole]

Hi Wim. Yes, I did hear that there was some good conditions lately, sadly
I've never been sat at my station at the right time! I shall program in the
repeater, though, ready for future opportune moments!

--
STC / M0TEY /
http://twitter.com/ukradioamateur

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
> El 13-Mar-16 a las 17:16, Stephen Thomas Cole escribió:
>> I've been mulling for a while that it'd be nice to have a QSO with some of
>> the ukra/ukram users, and a very nice chat just now with a former ukra
>> poster, Andy G0FTD, on GB3RE suggests that repeaters might be a good place
>> to start!
>>
>> I'm not in a great spot at this QTH for VHF/UHF, there's a lot of geography
>> in my way in most directions. But I can access the following:
>>
>> GB3IK
>> GB3KN
>> GB3DA
>> GB3KI on 2m
>>
>> & GB3RE on 70cm.
>>
>> Can anybody else open any of these up?
>>
>> In my car, at the top of the valley here, I can open up many of the London
>> repeaters, as well as Ipswich and Norfolk (with a good wind behind me) and
>> likely more. Would be great if there's anyone who can get in to the
>> repeaters I can work from home, though!
>>
>

> If you are near the coast towards Netherlands, and there is some tropo,
> try the reach PI2NOS, 430.125 MHz (+1.6 MHz shift for the input frequency).
><snip>

I just worked PI2NOS! There's tropo up now and the Dutch repeater is 5&9+++
to South-East England! My mind is blown. I just talked to Holland on 70cm!
Brilliant.

Conditions just starting to fluctuate as I write this, audio getting a bit
scratchy. But, man, that was FUN! :)

[Tim Hague]

Stephen, don't mind me saying but you live in the Medway towns. With flat conditions you should be able to work PA and ON on SSB with a basic small beam.
FM repeaters were really not designed for this type of operation.

73. Tim M0AFJ/G8GGP

[Wimpie]

El 05-Jun-16 a las 20:23, Stephen Thomas Cole escribió:
> Wimpie <wima...@tetech.nl> wrote:
>> El 13-Mar-16 a las 17:16, Stephen Thomas Cole escribiĂł:

>>> I've been mulling for a while that it'd be nice to have a QSO with some of
>>> the ukra/ukram users, and a very nice chat just now with a former ukra
>>> poster, Andy G0FTD, on GB3RE suggests that repeaters might be a good place
>>> to start!
>>>
>>> I'm not in a great spot at this QTH for VHF/UHF, there's a lot of geography
>>> in my way in most directions. But I can access the following:
>>>
>>> GB3IK
>>> GB3KN
>>> GB3DA
>>> GB3KI on 2m
>>>
>>> & GB3RE on 70cm.
>>>
>>> Can anybody else open any of these up?
>>>
>>> In my car, at the top of the valley here, I can open up many of the London
>>> repeaters, as well as Ipswich and Norfolk (with a good wind behind me) and
>>> likely more. Would be great if there's anyone who can get in to the
>>> repeaters I can work from home, though!
>>>
>>
>> If you are near the coast towards Netherlands, and there is some tropo,
>> try the reach PI2NOS, 430.125 MHz (+1.6 MHz shift for the input frequency).
>> <snip>
>
> I just worked PI2NOS! There's tropo up now and the Dutch repeater is 5&9+++
> to South-East England! My mind is blown. I just talked to Holland on 70cm!
> Brilliant.
>
> Conditions just starting to fluctuate as I write this, audio getting a bit
> scratchy. But, man, that was FUN! :)
>

It is/was exxcccellent. I had to work today, so I turned on the TRX at
19:30UTC.

Now a Dutchman around Dover is still making QSOs. UK signals reached far
inlands (Apeldoorn). Also G7HFS is talking (and opening virtually all
receivers).

Nice to read that you worked PI2NOS!

[Stephen Thomas Cole]

Tim Hague <m0...@yahoo.co.uk> wrote:
> Stephen, don't mind me saying but you live in the Medway towns. With flat
> conditions you should be able to work PA and ON on SSB with a basic small beam.

I don't doubt it. Alas, I don't have a beam or an SSB VHF/UHF radio.

> FM repeaters were really not designed for this type of operation.
>

How so? It's just a bit of fun, taking advantage of out-of-the-ordinary
conditions.

[Brian Howie]

In message <nj1qna$dbb$1...@stc.eternal-september.org>, Stephen Thomas Cole
<use...@stephenthomascole.com> writes

>
>I just worked PI2NOS! There's tropo up now and the Dutch repeater is 5&9+++
>to South-East England! My mind is blown. I just talked to Holland on 70cm!
>Brilliant.
>
>Conditions just starting to fluctuate as I write this, audio getting a bit
>scratchy. But, man, that was FUN! :)
>

Have a listen for the beacons :-

http://www.beaconspot.eu/beaconm.php?bandmhz=432

First to come up for me is PI7CIS or LA3UHF, but I'm hearing nothing.
The local 23cm beacon GB3EDN was reported in SM yesterday. I'll just
have to keep listening.

Brian
--
Brian Howie

[Guy G4DWV/4X1LT]

On Sun, 5 Jun 2016 12:32:42 -0700 (PDT), just as I was about to take a
herb, Tim Hague <m0...@yahoo.co.uk> disturbed my reverie and wrote:

>FM repeaters were really not designed for this type of operation.

To use a quaint American phrase,"Don't piss on his parade". It is a
small World and you should be happy he is.

I got a similar buzz working the Mount Olympus repeater from my third
floor flat in 4X using a Yaesu handie. Was I 'naughty' too?
--

73 de Guy G4DWV/4X1LT

[Stephen Thomas Cole]

Thanks, and yeah, "buzz" is the right word, it was brilliant! :)

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
> El 05-Jun-16 a las 20:23, Stephen Thomas Cole escribió:
>> Wimpie <wima...@tetech.nl> wrote:

>>> El 13-Mar-16 a las 17:16, Stephen Thomas Cole escribió:

Thanks for giving me the heads up on it, Wim. I programmed it in to my
radio when you mentioned it and it was a real buzz, when I turned on the
radio after seeing someone on Twitter say that there was a lift on, to hear
Dutch accents booming in when I switched to the memory channel. I had a
couple of brief QSOs before getting out of the way to allow other stations
to get in. Was very happy. I got the wife in to have a listen a little
later when it was Dutch language QSOs and she translated a bit for me. :)

[Stephen Thomas Cole]

Cheers, will do. PI2NOS came back up strong not long after I posted that
message, was absolutely crystal clear till about 10pm. I also spent about
45 minutes trying to bust through a pile-up PD3MR was working on 2m but
didn't have any luck there, I think nearly everybody in the UK was calling
him.

[Tim Hague]

I wasn't trying to piss on Stephens parade as our American friend so succinctly puts it, I just want to encourage folks to get active and see what they can work when there are no propagation enhancements. Stephen said he doesn't have SSB or CW capabilities, fair enough.
I had 2 quick QSO's this morning, one into Hamburg at 730kms and over towards the SP border at 930kms..I have a poor site to the east...

[Brian Howie]

In message <nj2v0s$q6g$2...@stc.eternal-september.org>, Stephen Thomas Cole
<use...@stephenthomascole.com> writes

I got a nice buzz working through OSCAR 7 on 70cm/2m for the first time
in 1975. I worked out the orbits using an 8 bit FORTRAN program. I
was only running 5W and it was weird listening to my own delayed signal
and trying to manually track the doppler at the same time.
I was envious of my mate across town, who worked Anchorage on a very
marginal orbit. I never managed that. There's still time as OSCAR 7 came
back from the dead a few years ago.

Brian
--
Brian Howie

[Brian Reay]

I recall the 'buzz' when Helen Sharma responded from Mir.

One of my daughters, just after she was licenced, used Howard's (G6LVB)
callsign when he was doing a demo at one of the rallies using his Arrow
antenna during one of the satellite passes. She was delighted.

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
>
>
> We also have an almost nationwide 2m repeater (PI3UTR, 145.575 MHz out,
> -0.6 MHz shift). I don't know the current situation, but they
> experimented with about 10 Hz offset between TX carriers. I could notice
> that. Two signals arrived at my location. When turning my 2 m sector
> antenna I could eliminate (or enhance) the annoying effect.
>
> Technically both PI2NOS and PI3UTR are a real succes, and UK based Radio
> Amateurs worked them already over the air.
>
> It is now becoming a social experiment..., as some Neandertaler type of
> person (or even worse single-celled) is able to jam the system.
>

Following the chat here a few days ago where repeater culture was touched
on, I've dived into the archive here as I knew Wim had spoken regarding the
Dutch national repeaters before.

What I'm musing over is whether such a system could work here, what the
pitfalls might be, and whether it'd prove popular and see use. Looking at
possible pitfalls, the spectre of repeater jamming looms large and is be
interested to hear from Wim regarding what he seems to allude to above;
Neanderthal types jamming the whole system up. Is that something that has
been a common issue on Holland's systems?

Other than that, does anybody have any commentary regarding the
practicalities of getting a distributed analogue repeater on the air? Is
there an uncontested space on 2m where this could live happily? How many
sites would be the minimum to provide acceptably "nationwide" coverage?

Digital systems are, unquestionably, a big part of the future but there's
so much easy to use analogue gear in circulation (and particularly so with
the dreaded cheap Chinese handsets) that such a system would have very
little barrier of entry, certainly as compared to DMR, D-Star, and even
EchoLink and the type.

Consider this a thought experiment of sorts. I think that a GB3BRIT, say,
system that would allow north and south, east and west of the UK to all
communicate at any time would be a good thing for our radio community, and
if some discussion here helps form up the proposition perhaps it's
something I'll start writing to the RSGB, OFCOM and regional repeater
groups about. :)

[Brian Reay]

I'm pretty sure there is already a linked system of repeaters in the
west country. I stumbled across it when programming up a radio for one
of our jaunts. I think it is towards Bath.

The 'issue' would be funding. Most repeater groups run on a 'shoe
string', you would be surprised how few people contribute to their local
repeater group. We are lucky with 'IK (both of them) as the keeper funds
them himself but the other repeaters in Kent are funded by the KRG (at
least I don't think there are any others which aren't) and all too few
amateurs 'chip in'. True, these days, usage is limited, but the same was
true when you almost had to 'book a slot'.

Throw in the fact that few repeater sites probably have a internet link
(part of the reason Echolink is 'clunky' as you mentioned the other day)
and the scale of the problem is becoming clear.


Don't get me wrong, I'm not against the idea, in fact I would quite like
to see some of our local repeaters linked (there are some 'dead spots'
it could help with) but I fear getting people to support the idea, when
funding is tight and usage low, is unlikely.

[Tim Hague]

I feel that there are quite enough repeaters already, the digital ones can be linked (certainly the DSTAR ones can). They are rarely used anyway...we have 2 in Milton Keynes, one DSTAR, the,other fusion/ analogue and they are both quiet.
The other thing as Brian has said is who is going to build and fund it?, Trying to get amateurs to pay for anything is like getting blood out of a stone.

I'd much prefer to encourage folks onto the weak signal modes, be it SSB, Digital or dare I say it CW, you learn a lot more on those modes than waffling on a repeater.

73. Tim M0AFJ

[Brian Reay]

While I agree with your last comment Tim, I think the two aims are not
mutually exclusive. After all, the modes you list aren't ones which can
readily be used when mobile (including as a pedestrian) when linked
repeaters would be more useful.

I know that people do, or at least did, use repeaters from home but
these days they are rarely used, as I think we are agreed. Perhaps if
there was a linked system introduced people would, initially, use them
from home (as we saw with Echolink for example) but it may also
stimulate more mobile use.

I don't think a linked system means more repeaters, in fact I don't
think there is 'space' for them- as I recall all the available channels
are allocated and anyone wishing to establish a new repeater needs to
wait for a closedown, at least on 2m and probably on 70cm.

I certainly wouldn't advocate or support anymore frequencies/channels
being allocated to repeaters. The current 'mix' is about right in my
view, at least on VHF/UHF. (I'd like to see some dedicated AM 'space' on
HF for the VMARS boys but that is another matter.)

All in all, I'm not against the idea, I'm have a very much 'live and let
live' attitude to how people use the bands, provided they stay legal and
don't cause other amateurs problems. If people want linked repeaters, I
certainly wouldn't oppose it. My one concern, at least for an analogue
system, is the scope for abuse. With digital systems, you need to be
registered with the system. While that isn't perfect, it does limit the
scope for abuse.

[Wimpie]

El 06-Jan-17 a las 15:08, Stephen Thomas Cole escribió:

Hello Stephen, and of course the other readers of this group,

To be honest Stephen, jamming is a serious issue on our national 70 cm
repeater. Availability of Chinese equipment certainly contributed to
this. Sadly to say, some licensed Amateurs also misbehave.

Till now the benefits (still) win. The PI2NOS system is used by both
mobile and base stations. Many Amateurs reactivated themselves and found
old fellow hams. An increasing number of UK Amateurs use PI2NOS.

Repeater management can handle jamming to some extend:
-receivers can be turned on and off on the fly (and this happens)
-CTCSS can be activated on receivers experiencing frequent "attacks"
(some receivers have CTCSS now)
-triangulation together with "fox hunting" is used to trace down
jamming activities, making law enforcement more effective.
-Turning-off the complete system in case of an unmanagable situation
(this sometimes/seldom occurs).

Did you know we have a receiver at 438.625 MHz? Something interesting
for UK Amateurs: The Location is Breskens and it has a 12 dBi (vert.
pol.) corner reflector antenna pointing to the UK, no CTCSS. For more
info visit PI2NOS.NL. Try to locate "PI2NOS adds a special UK receiver".
There is also a linked repeater at curacao (North of Venezuela).

[Stephen Thomas Cole]

Hello Wim, thanks for replying.

> To be honest Stephen, jamming is a serious issue on our national 70 cm
> repeater. Availability of Chinese equipment certainly contributed to
> this. Sadly to say, some licensed Amateurs also misbehave.

That's sad to hear, but not a surprise. In the discussions we've had in the
group recently the motivations behind jamming were touched on and consensus
seems that some folk are just wired that way, with a need for disruption
and attention-seeking. Interestingly, the notion that some jammers consider
themselves on a righteous crusade was put forward, so it's a complicated
state of affairs!

> Till now the benefits (still) win. The PI2NOS system is used by both
> mobile and base stations. Many Amateurs reactivated themselves and found
> old fellow hams. An increasing number of UK Amateurs use PI2NOS.
>
> Repeater management can handle jamming to some extend:
> -receivers can be turned on and off on the fly (and this happens)
> -CTCSS can be activated on receivers experiencing frequent "attacks"
> (some receivers have CTCSS now)
> -triangulation together with "fox hunting" is used to trace down
> jamming activities, making law enforcement more effective.
> -Turning-off the complete system in case of an unmanagable situation
> (this sometimes/seldom occurs).

In my experience, troublemakers feed on reaction and if they're ignored
they eventually go away. Closing down receivers that are allowing jammers
into the system would resolve a problem in the short term but it's very
likely to incite the jammer to chase for the same reaction again, and
again, and so on. That said, with a nationwide system, leaving a jammed
receiver operational brings the whole thing to a grinding halt.

You say that the benefits outweigh the negatives, though. What's the
approximate balance of peaceful operation to jammed? 80% vs 20%? 90% vs
10%?

> Did you know we have a receiver at 438.625 MHz? Something interesting
> for UK Amateurs: The Location is Breskens and it has a 12 dBi (vert.
> pol.) corner reflector antenna pointing to the UK, no CTCSS. For more
> info visit PI2NOS.NL. Try to locate "PI2NOS adds a special UK receiver".
> There is also a linked repeater at curacao (North of Venezuela).
>

Excellent, thanks for that, I'll look it up!

[Stephen Thomas Cole]

Tim Hague <m0...@yahoo.co.uk> wrote:
> I feel that there are quite enough repeaters already, the digital ones
> can be linked (certainly the DSTAR ones can). They are rarely used
> anyway...we have 2 in Milton Keynes, one DSTAR, the,other fusion/
> analogue and they are both quiet.
> The other thing as Brian has said is who is going to build and fund it?,
> Trying to get amateurs to pay for anything is like getting blood out of a stone.
>

National Lottery funding would be a good option, certainly for the initial
"build and launch". It'd be trivial to put together a pitch based around
community benefits of nationwide radio communications and there's scope
for a strong education narrative, around creating opportunities for schools
north and south to link up on the air. ALL pie in the sky stuff right now,
but certainly doable with effort.

> I'd much prefer to encourage folks onto the weak signal modes, be it SSB,
> Digital or dare I say it CW, you learn a lot more on those modes than
> waffling on a repeater.
>

I don't disagree, but all of those place far higher barrier-of-entry
requirements on the potential users, be it in equipment (SSB gear is
thinner on the ground than FM, and far more expensive), cost (digital gear
is pricey compared to analogue FM gear), or skills (CW takes at least a few
weeks to get to grips with, more like a few months if one isn't practicing
around the clock). An analogue FM distributed repeater would be,
comparatively, zero barrier of entry, which would have good and bad
implications. The good outweighs the bad, though, I think.

[Stephen Thomas Cole]

Ooh, interesting. A quick Google hasn't uncovered any info on that, I'll
have another look later when in front of my computer.

> The 'issue' would be funding. Most repeater groups run on a 'shoe
> string', you would be surprised how few people contribute to their local
> repeater group. We are lucky with 'IK (both of them) as the keeper funds
> them himself but the other repeaters in Kent are funded by the KRG (at
> least I don't think there are any others which aren't) and all too few
> amateurs 'chip in'. True, these days, usage is limited, but the same was
> true when you almost had to 'book a slot'.

Yes, funding would be an issue but a relatively resolvable one if the
project picked up steam. National Lottery grants could be applied for,
particularly if a community/education spin could be put to it.

> Throw in the fact that few repeater sites probably have a internet link
> (part of the reason Echolink is 'clunky' as you mentioned the other day)
> and the scale of the problem is becoming clear.

Does the Dutch system rely on Internet connections?

> Don't get me wrong, I'm not against the idea, in fact I would quite like
> to see some of our local repeaters linked (there are some 'dead spots'
> it could help with) but I fear getting people to support the idea, when
> funding is tight and usage low, is unlikely.

Agreed, the biggest problem is going to be convincing folk to get on board.
It's the kind of project that could really do with someone who's got more
money than sense just taking it upon themselves to spend spend spend and
set up a system covering a part of the country and let folk come round to
it or not.

[Paul Cummins]

In article <o4smnn$sdf$2...@stc.eternal-september.org>,

use...@stephenthomascole.com (Stephen Thomas Cole) wrote:

> equipment (SSB gear is
> thinner on the ground than FM, and far more expensive)

Build it...?

> (digital gear
> is pricey compared to analogue FM gear),

Again, Build It.

Experimentation and self-training, not chatting to others across the city
or county.

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981
Please Help us dispose of unwanted virtual currency:
Bitcoin: 1LzAJBqzoaEudhsZ14W7YrdYSmLZ5m1seZ

[Brian Reay]

On 08/01/2017 10:36, Jeff wrote:
>
>> Ooh, interesting. A quick Google hasn't uncovered any info on that, I'll
>> have another look later when in front of my computer.
>>
>

> Look up the South West Cluster; there are 8 or 9 DMR repeaters that link
> together on one of the 2 DMR channels at each repeater, the other
> carries the local repeater traffic only.
>
> Jeff


I'm sure it was an analogue cluster Jeff and I thought it was Bath way.
It was a while back, before I bought my DMR radio, so I doubt I would
have looked out digital repeaters.

As it happened, the plans for the jaunt changed and I never used the
data I collected.

[Stephen Thomas Cole]

Jeff <je...@ukra.com> wrote:
>
>> Ooh, interesting. A quick Google hasn't uncovered any info on that, I'll
>> have another look later when in front of my computer.
>>
>

> Look up the South West Cluster; there are 8 or 9 DMR repeaters that link
> together on one of the 2 DMR channels at each repeater, the other
> carries the local repeater traffic only.

I did see that, but my impression was Brian was referring to an analogue
system. Maybe he could confirm or deny?

[Andrew Marshall]

In message <o4t5a9$56e$1...@stc.eternal-september.org>, Stephen Thomas Cole
<use...@stephenthomascole.com> writes

>Jeff <je...@ukra.com> wrote:
>>
>>> Ooh, interesting. A quick Google hasn't uncovered any info on that, I'll
>>> have another look later when in front of my computer.
>>>
>>
>> Look up the South West Cluster; there are 8 or 9 DMR repeaters that link
>> together on one of the 2 DMR channels at each repeater, the other
>> carries the local repeater traffic only.

>I did see that, but my impression was Brian was referring to an analogue
>system. Maybe he could confirm or deny?

The 6m machines GB3FH and GB3ZY are linked, according to this page on
their website

<http://www.gb3fh.eclipse.co.uk/index_files/Page912.htm>

Other repeaters may also be linked, in that area or elsewhere.
--
Regards,
Andrew Marshall, G8BUR, M0MAA.

[Brian Reay]

On 08/01/2017 10:46, Stephen Thomas Cole wrote:
> Jeff <je...@ukra.com> wrote:
>>
>>> Ooh, interesting. A quick Google hasn't uncovered any info on that, I'll
>>> have another look later when in front of my computer.
>>>
>>
>> Look up the South West Cluster; there are 8 or 9 DMR repeaters that link
>> together on one of the 2 DMR channels at each repeater, the other
>> carries the local repeater traffic only.
>
> I did see that, but my impression was Brian was referring to an analogue
> system. Maybe he could confirm or deny?
>

I'm sure they were. I don't have DStar and, at the time I was looking
for repeaters to use on the jaunt, I didn't have DMR.

I'm sure it was in the Bath direction as we were heading to Wales and
that would be the route, with stop offs. As it happens, while we made
the trip, our first stop was further west so I didn't use the
information collected. We rarely take a direct route, the return was via
Oxford originally, although we changed our plans and stayed longer in
Brecon.

[Brian Reay]

The uk.repeater website may have details, look at the links to repeaters
in the area between London and Wales, south of the M4.

[Wimpie]

El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribió:
> Wimpie <wima...@tetech.nl> wrote:
>> El 06-Jan-17 a las 15:08, Stephen Thomas Cole escribiĂł:

Most Amateurs over here have the same opinion and operate based on this
opinion. I believe there is some inverse relation between the signal to
noise ratio of conversations and the probability of "activating"
troublemakers.

> Closing down receivers that are allowing jammers
> into the system would resolve a problem in the short term but it's very
> likely to incite the jammer to chase for the same reaction again, and
> again, and so on. That said, with a nationwide system, leaving a jammed
> receiver operational brings the whole thing to a grinding halt.

Doing nothing renders the systems useless, so temporary disabling a
receiver (or some receivers) keeps the system on the air only affecting
a limited area.

Most unlicensed transmissions are from people using portable equipment
with bad antennas, so only a small number of receivers is affected.
When Ameteurs with a good setup misbehave (due to intoxication or some
disorder?), then short term options are limited. PA-country is small and
relatively flat, so somebody with say 50W at the antenna and a good
antenna installation may reach >50% of all receivers.

>
> You say that the benefits outweigh the negatives, though. What's the
> approximate balance of peaceful operation to jammed? 80% vs 20%? 90% vs
> 10%?

Fortunately it is better then 90% vs 10%, thanks to the users and not to
forget the repeater team.

>
>> Did you know we have a receiver at 438.625 MHz? Something interesting
>> for UK Amateurs: The Location is Breskens and it has a 12 dBi (vert.
>> pol.) corner reflector antenna pointing to the UK, no CTCSS. For more
>> info visit PI2NOS.NL. Try to locate "PI2NOS adds a special UK receiver".
>> There is also a linked repeater at curacao (North of Venezuela).
>>
>
> Excellent, thanks for that, I'll look it up!
>


--

[Wimpie]

El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribió:

>

> Does the Dutch system rely on Internet connections?
>
>

As far as I know, it may use both Hamnet and Internet. The overall
latency of both PI3UTR and PI2NOS is in the some 100 ms range.

[Brian Reay]

On 08/01/2017 20:03, Wimpie wrote:
> El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribió:
>> Wimpie <wima...@tetech.nl> wrote:

>>> El 06-Jan-17 a las 15:08, Stephen Thomas Cole escribió:

Are your licensing authority active in enforcement, ie dealing with
those who cause problems?

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
>>
>> In my experience, troublemakers feed on reaction and if they're ignored
>> they eventually go away.
>
> Most Amateurs over here have the same opinion and operate based on this
> opinion. I believe there is some inverse relation between the signal to
> noise ratio of conversations and the probability of "activating"
> troublemakers.

Yes, agreed. Now you mention it, the conversations that I've heard jammed
have tended to be more "casual ragchew" than technical chatter. I wonder if
there's conclusions to infer from that about the type of person doing the
jamming... does it suggest a likelihood that the jammer is a license holder
with stuffy ideas about what calibre of conversation should be transmitted?
Food for thought.

>> Closing down receivers that are allowing jammers
>> into the system would resolve a problem in the short term but it's very
>> likely to incite the jammer to chase for the same reaction again, and
>> again, and so on. That said, with a nationwide system, leaving a jammed
>> receiver operational brings the whole thing to a grinding halt.
>
> Doing nothing renders the systems useless, so temporary disabling a
> receiver (or some receivers) keeps the system on the air only affecting
> a limited area.
>
> Most unlicensed transmissions are from people using portable equipment
> with bad antennas, so only a small number of receivers is affected.
> When Ameteurs with a good setup misbehave (due to intoxication or some
> disorder?), then short term options are limited. PA-country is small and
> relatively flat, so somebody with say 50W at the antenna and a good
> antenna installation may reach >50% of all receivers.
>
>>
>> You say that the benefits outweigh the negatives, though. What's the
>> approximate balance of peaceful operation to jammed? 80% vs 20%? 90% vs
>> 10%?
>
> Fortunately it is better then 90% vs 10%, thanks to the users and not to
> forget the repeater team.

That's good to hear, and reassuring. The disruptive element is only a very
small minority, that's always worth remembering even if it's hard to in the
middle of listening to a jammed repeater!

[FranK Turner-Smith G3VKI]

"Stephen Thomas Cole" <use...@stephenthomascole.com> wrote in message
news:o4smnn$sdf$2...@stc.eternal-september.org...

> Tim Hague <m0...@yahoo.co.uk> wrote:
>> I feel that there are quite enough repeaters already, the digital ones
>> can be linked (certainly the DSTAR ones can). They are rarely used
>> anyway...we have 2 in Milton Keynes, one DSTAR, the,other fusion/
>> analogue and they are both quiet.
>> The other thing as Brian has said is who is going to build and fund it?,
>> Trying to get amateurs to pay for anything is like getting blood out of a
>> stone.
>
> National Lottery funding would be a good option, certainly for the initial
> "build and launch". It'd be trivial to put together a pitch based around
> community benefits of nationwide radio communications and there's scope
> for a strong education narrative, around creating opportunities for
> schools
> north and south to link up on the air. ALL pie in the sky stuff right now,
> but certainly doable with effort.

Eh? We've already got mobile phones. What's the difference?

>
>> I'd much prefer to encourage folks onto the weak signal modes, be it SSB,
>> Digital or dare I say it CW, you learn a lot more on those modes than
>> waffling on a repeater.
>
> I don't disagree, but all of those place far higher barrier-of-entry
> requirements on the potential users, be it in equipment (SSB gear is
> thinner on the ground than FM, and far more expensive), cost (digital gear
> is pricey compared to analogue FM gear), or skills (CW takes at least a
> few
> weeks to get to grips with, more like a few months if one isn't practicing
> around the clock). An analogue FM distributed repeater would be,
> comparatively, zero barrier of entry, which would have good and bad
> implications. The good outweighs the bad, though, I think.
>

Mobile phones have "zero barrier of entry." I ask again, what's the
difference?
--
;-)
.
73 de Frank Turner-Smith G3VKI - mine's a pint.
.
http://turner-smith.uk

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
> El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribió:
>
>>
>> Does the Dutch system rely on Internet connections?
>>
>>
> As far as I know, it may use both Hamnet and Internet. The overall
> latency of both PI3UTR and PI2NOS is in the some 100 ms range.
>

Do you know if they just use the Internet for syncing purposes or do the
systems rely on the Internet for tx/tx beyond that?

[Brian Reay]

On 09/01/17 09:07, Stephen Thomas Cole wrote:
> Wimpie <wima...@tetech.nl> wrote:
>>>
>>> In my experience, troublemakers feed on reaction and if they're ignored
>>> they eventually go away.
>>
>> Most Amateurs over here have the same opinion and operate based on this
>> opinion. I believe there is some inverse relation between the signal to
>> noise ratio of conversations and the probability of "activating"
>> troublemakers.
>
> Yes, agreed. Now you mention it, the conversations that I've heard jammed
> have tended to be more "casual ragchew" than technical chatter. I wonder if
> there's conclusions to infer from that about the type of person doing the
> jamming... does it suggest a likelihood that the jammer is a license holder
> with stuffy ideas about what calibre of conversation should be transmitted?
> Food for thought.

While it was often claimed only 'casual' conversations were jammed, it
isn't anything but true.

No doubt the claims are an attempt to somehow justify the actions of the
jammers, who where generally licensed*, the facts simply don't reflect
the claims. In particular, 'LO was jammed for hours at a time, not least
by people who had 'parked up' on the parade at Crystal Palace to do so.

Besides, no amateur has the right to deny access to a repeater etc. on
the basis that he dobe jammed out of existence years ago.
esn't like the calibre of conversation. Heavens above, 80m would have
been jammed out of existence years ago.

*There was a successful court case against several licensed amateurs.
Besides fines, their licenses were suspended/removed. At least one
other amateur had his license suspended.

I'm sure the case was reported in RadCom, it must have been around
1978/9, it wasn't long before I completed my engineering degree.

[Jerry Stuckle]

When Hurricane Sandy went up the East Coast of the U.S. in 2012, most
land lines went down - including cell phones, which require land lines
to connect the tower to the central station. Those which didn't lose
their land lines often lost power. And since their generators only had
enough fuel for 24 hours (FCC requirements at the time), after a day,
they went down. Many people, including much of New York, were left
without any communications.

But ham repeaters with sufficient backup power (several were in
buildings with extended power sources) kept going.

A similar case happened on a smaller scale here in Washington, DC, when
a derecho went through in June of 2012. Again, many phones were out,
including cell phones, due to lines being out. But the repeaters here
kept going.

And in 2011, when an earthquake hit central Virginia and was felt here,
cell towers were not damaged. But the system was immediately overloaded
by people trying to make calls, resulting in a system unusable for
emergency communications and not much good for anything else for several
hours.

Cell phones are great when they work. But too many things can cause
them to fail. That's why the head of FEMA values hams so much. We come
through when everything else (including cell phones) fails.

--
==================
Remove the "x" from my email address
Jerry, AI0K
jstu...@attglobal.net
==================

[Stephen Thomas Cole]

With respect, you could use that logic to negate the whole hobby for the
last 20 years! And why not extend it back to the 60/70s when landline
phones became common? You could easily say that amateur radio has been
obsolete for 50 years!

[Brian Reay]

Unless you are in the habit of making random calls to strangers, surely
you know the answer.

Seriously, when non-amateurs say that, I let them listen to a real QSO.
They see the difference immediately, it has never failed.

Having a repeater 'in the middle', even a linked one, makes no difference.

If you don't like repeaters, or any of the other ideas, simply don't use
them. They aren't compulsory. There is space on the bands for people to
enjoy the hobby without using repeaters etc.

[mm0fmf]

This is the UK where the WX is nowhere as extreme as in the USA and the
areas to be covered in the event of an emergency are trivially small.

[Wimpie]

El 09-Jan-17 a las 10:07, Stephen Thomas Cole escribió:
> Wimpie <wima...@tetech.nl> wrote:
>> El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribiĂł:

>>
>>>
>>> Does the Dutch system rely on Internet connections?
>>>
>>>
>> As far as I know, it may use both Hamnet and Internet. The overall
>> latency of both PI3UTR and PI2NOS is in the some 100 ms range.
>>
>
> Do you know if they just use the Internet for syncing purposes or do the
> systems rely on the Internet for tx/tx beyond that?
>

Synchronisation (both RF carrier and modulation) to reduce co-channel
interference use a GPS derived reference.

All TCP/IP "transmitted" audio fragments have a designated time stamp in
the future to handle TCP/IP delay. Fragments are tranmitted (TCP/IP)
from a central server, stored/buffered at the transmitter sites and then
simultaneously modulated onto the RF carrier based on the GPS derived
time and the time stamp of the fragment. The delay is dynamic and
therefore determined by the TCP/IP path with longest delay.

You will find some Dutch technical info on www.hobbyscoop.nl. Select
"systemen" and then "PI2NOS". An online translator may produce something
that you may recognize as English. When you would like to know the
details, try to get in contact with PA1OKZ or PE1CHL.

Law Enforcement.
Our "OFCOM" (Agentschap Telecom) is active (with positive outcome). Of
course when some air band frequency experiences interference, priority
is fully clear. Our yearly fee is EUR 31.-- (both Novice and Full).

--
Wim, PA3DJS
Tell your pigeon to remove abc from the address.

[Jim GM4DHJ ...]

"FranK Turner-Smith G3VKI" <g3...@turner-smith.uK> wrote in message
news:o4vj2n$kor$1...@dont-email.me...

you can choose who you talk to on a mobile phone .....

[FranK Turner-Smith G3VKI]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message
news:o5055r$iv5$1...@jstuckle.eternal-september.org...

Several good points well made.
Happy 2017, Jerry.

[mm0fmf]

I like Brian's idea that if people want to do something and it doesn't
stop other people doing other things then it is of no concern to me. But
I have to agree with Frank that such a network is solving a problem that
doesn't exist.

There are a plethora of existing repeater networks that are hardly
bursting with activity such that yet another is needed. At the basic
level, there is insufficient use of what is in place now to warrant
further spectrum being allocated to such an idea unless it's spectrum
currently allocated for repeaters etc. being reallocated.

[Jerry Stuckle]

It still happens. And when it does, cell phones are worthless.

[Jim GM4DHJ ...]

"mm0fmf" <no...@invalid.com> wrote in message
news:o50o6d$vug$1...@dont-email.me...

when I was working RAENET was below the salvation army on the civil
contingencies contact list but my call out cellphone was to be given
priority in an emergency but as you say the big one never happened
......That is probably why with other reasons of poor standard of licensees
ham radio and RAENET in the UK is considered to be no more than a joke by
the authorities.....

[Brian Howie]

In message <o50o6d$vug$1...@dont-email.me>, mm0fmf <no...@invalid.com>
writes

Instances of flooding in the UK seems to be increasing
At the end of 2015 flooding took out the Newton Stewart telephone
exchange .All telephone and internet coverage were down for a few hours

Dumfries and Galloway Raynet members provided emergency communications.
I understand they are now setting up a network of linked repeaters along
the Solway Coast as this sort of event may occur again.


Brian
--
Brian Howie

[Roger Hayter]

Your general point I thoroughly agree with. But, on the timescale, you
should be aware that 60 years ago a transatlantic call cost a week's
wages and had to be booked in advance. And they did not become
commonplace and cheap for ordinary people for a considerable number of
years after that. The 'phone patch system that American amateurs
operated for third parties was much valued.



--

Roger Hayter

[Roger Hayter]

In this country, at least in London, there is a scheme to allow the
emergency services to progressively restrict public access to the mobile
(cell) telephone system mainly to reserve it for emergency service use
but also to restrict the spread of information which might cause panic.
This can be done very rapidly.

Perhaps you have this sort of scheme in urban areas, or would it be
considered an unwarranted interference in private affairs?


--

Roger Hayter

[Stephen Thomas Cole]

Wimpie <wima...@tetech.nl> wrote:
> El 09-Jan-17 a las 10:07, Stephen Thomas Cole escribió:
>> Wimpie <wima...@tetech.nl> wrote:

>>> El 08-Jan-17 a las 07:37, Stephen Thomas Cole escribió:

>>>
>>>>
>>>> Does the Dutch system rely on Internet connections?
>>>>
>>>>
>>> As far as I know, it may use both Hamnet and Internet. The overall
>>> latency of both PI3UTR and PI2NOS is in the some 100 ms range.
>>>
>>
>> Do you know if they just use the Internet for syncing purposes or do the
>> systems rely on the Internet for tx/tx beyond that?
>>
>
> Synchronisation (both RF carrier and modulation) to reduce co-channel
> interference use a GPS derived reference.
>
> All TCP/IP "transmitted" audio fragments have a designated time stamp in
> the future to handle TCP/IP delay. Fragments are tranmitted (TCP/IP)
> from a central server, stored/buffered at the transmitter sites and then
> simultaneously modulated onto the RF carrier based on the GPS derived
> time and the time stamp of the fragment. The delay is dynamic and
> therefore determined by the TCP/IP path with longest delay.
>
> You will find some Dutch technical info on www.hobbyscoop.nl. Select
> "systemen" and then "PI2NOS". An online translator may produce something
> that you may recognize as English. When you would like to know the
> details, try to get in contact with PA1OKZ or PE1CHL.

Fab. Thanks for all the info, Wim. Hugely appreciated.

[Stephen Thomas Cole]

Who's trying to solve a problem? :-) It's just an idea for something that
doesn't yet exist in this country and, if it did, it might prove useful to
some amateurs.

> There are a plethora of existing repeater networks that are hardly
> bursting with activity such that yet another is needed. At the basic
> level, there is insufficient use of what is in place now to warrant
> further spectrum being allocated to such an idea unless it's spectrum
> currently allocated for repeaters etc. being reallocated.

A common complaint re VHF/UHF is that they're "dead", essentially unused
and going to waste. If that's accepted as the reality, why not hive off a
couple of frequencies for this?

[Stephen Thomas Cole]

Brian Howie <br...@b-howie.demon.co.uk> wrote:
> Instances of flooding in the UK seems to be increasing
> At the end of 2015 flooding took out the Newton Stewart telephone
> exchange .All telephone and internet coverage were down for a few hours
>
> Dumfries and Galloway Raynet members provided emergency communications.
> I understand they are now setting up a network of linked repeaters along
> the Solway Coast as this sort of event may occur again.

Digital, I presume?

[Ian Jackson]

In message <o52802$8sr$3...@stc.eternal-september.org>, Stephen Thomas Cole
<use...@stephenthomascole.com> writes

One of the advantages of amateur radio is that, in dire 'all else has
failed' emergencies, it can provide at least some form of ad hoc
communication facility.

One of the dangers of planning to deal with such situations by setting
up hi-tech methods of communication, is that they themselves could be
one of the things that have failed.
--
Ian

[Roger Hayter]

Do you know whether the systems the emergency services use allow direct
communication between handsets? Or whether they have emergency mobile
base stations? Both ot those would seem desirable criteria for an
emergency service radio system. But perhaps they are just too difficult
to provide.




--

Roger Hayter