648 kHz Mediumwave AM broadcast site and tour of transmitter and antenna installation
LBP
17 minute video just uploaded by Jonathan Marks shot at Orfordness in
2003 where he interviews and is shown round by engineer Andy
Matheson.
There are also references to Crowborough where Andy worked and the
Aspidistra transmitter, parts of which are preserved at Orfordness.
Andy also mentions the 50kw transmitter, originally intended for the
Mi Amigo which instead went at short notice to Bechuanaland during the
Rhodesia crisis, then to Crowborough, later used at Canewdon to jam
RNI, taken back to Crowborough and ended up at Orfordness.
Entitled Tribute to BBC 648 kHz Orfordness - The Geeks Version it goes
into some detail about the antennas and transmitters used.
Special thanks to Mike Barraclough for bringing this video to my
attention.
Click this link
LBP
Part One of one of the most popular documentaries broadcast in 1993,
looking at UK black propaganda. Features interview with the late
Harold Robin, the engineer who put a number of "fake" resistance
stations on the air from a transmitter site not far from Bletchley
Park. I was glad to see that they haven't forgotten the role of these
broadcasts - it's mentioned in the exhibition. Part Two is further up
the file collection (see March 22nd 2010).
Direct download:
http://traffic.libsyn.com/jonathanmarks/WartimeDeceptionPart1.mp3
Station X
To me it seems the pomms like to have everything their own way.
Why on earth would you use a MW freq to try and get into Europe? The
aerial arrays are a little odd to me. Where's the curtain arrays for
SW and the Rhombics.
Oh around the back of 648khz the signal is shit. Yup butin Amsterdam
it's great! Well Hello? Medium wave is for local stuff ladies! We all
know it skips at night. But for F++k sake. No wonder Radio Caroline is
having such an issue.
Nah typical aristocrosy crap - oh we don't want the Euro! Don't start
me looks like my services are needed over there too!
Station X
The vid on UK Radio Player is interesting too. The first statement
about people only staying online for a little while and the pc is hard
to use as everyone's player is different. I'll give them the last bit!
But hello dick head!
PEOPLE ARE SCARED OF DOWNLOAD FEES YOU SILLY GIT!
The day you get your internet for X dollars and there you go there's
your 2mbit connection with no data counting - look out it will be on!
FM has multipathing issues and is fucked in a office around pc's. AM
totally toast in that same office. But better distance covered in the
car for the same power in flat country.
A pc on a good connection that doesn't give a shit about downloads -
he he! Yup I'm in! That means I could listen to Virgin Radio
(Absolute) here in Oz all day in FULL QUALITY just like it was the
local FM on my tuner!
Wake up maggots!
LBP
> Very interesting LBP. I've got a few questions after watching the vid.
> To me it seems the pomms like to have everything their own way.
>
Well it is the BBC after all !!
> Why on earth would you use a MW freq to try and get into Europe? The
> aerial arrays are a little odd to me. Where's the curtain arrays for
> SW and the Rhombics.
>
648 kHz / 462 metres is towards the low end of mediumwave and with
enough power
250 - 500 KW and a directional array type antenna with propagational
gain then the groundwave
should reach across the the sea into mainland Europe.
Mediumwave is far more popular than shortwave so using this part of
the spectrum does make sense.
The antenna farm
http://en.wikipedia.org/wiki/File:Orfordness_transmitting_station.jpg
The station has two directional aerial systems: one for 648 kHz and
one for 1296 kHz.
The directional aerial for 648 kHz consists of a row of five 106.7
metre (350 ft) high freestanding steel lattice towers of triangular
cross section, insulated at their base. All five towers are driven.
The directional aerial for 1296 kHz consists of six freestanding steel
lattice towers. Unlike the directional aerial for 648 kHz, they are
arranged in two parallel rows with three towers in each. Only the
middle tower of each three is driven: the other towers act as passive
reflector and director elements.
There is also a back-up omni-directional mast radiator for 648 kHz.
This has only been used when maintenance work is carried out on the
directional antenna, since it can only work at 200 kW.
> Oh around the back of 648khz the signal is shit. Yup butin Amsterdam
> it's great! Well Hello? Medium wave is for local stuff ladies! We all
> know it skips at night. But for F++k sake. No wonder Radio Caroline is
> having such an issue.
>
The intention was to deliver programming into Europe by remote control
using the UK as the transmitter base.
At the time I suppose they couldn't just waltz up and stake a claim on
a few acres of land in The Netherlands or the Benelux
and set up their Colonial broadcasting operations.
It had to be done out of the home country - and of course the UK is
very close to main land Europe so it was feasible.
The transmitter site was right next to the North Sea on marsh land
situated on the south east coast of the UK.
The view the TX site - go to google and type in "orford ness United
Kingdom" and you can navigate around and see the
antenna farm and transmitter building.
RADIO CAROLINE
Radio Caroline did the same sort of thing by transmitting into the UK
and Europe outside territorial waters
by positioning their radio ship beyond the 3 mile limit in free
international waters so as to circumvent the UK radio regulatory
framework -
which worked up to 1966 and then the MOA (Marine Offences Act) closed
that loophole (a long story in itself..).
There are many chapters in the Radio Caroline story and they're still
going via Internet and Sky digital
as well as having regular RSL 1 watt MW AM transmissions.
Radio Caroline
531 AM - Tilbury, Essex
On air from: 21/04/11 to 02/05/11
The RSL details are listed on the Ofcom website
http://www.ofcom.org.uk/static/radiolicensing/rsls/current_list.htm
> Nah typical aristocrosy crap - oh we don't want the Euro! Don't start
> me looks like my services are needed over there too!
Frankly I don't blame Britain not wanting the Euro - all you have to
do is look at some of those countries
with hopeless economies that are being propped up by riding on the
coat tails of the more wealthy European countries.
LBP
> PS Back again!
>
> The vid on UK Radio Player is interesting too. The first statement
> about people only staying online for a little while and the pc is hard
> to use as everyone's player is different. I'll give them the last bit!
> But hello dick head!
>
Yes well, indeed :)
There are quite a few interesting videos and audios on this link well
worth investing some time in..
BearCave
> There are quite a few interesting videos and audios on this link well
> worth investing some time in..
>
Thanks for posting these.
One motivation for me divesting MF-NAS licenses last year was to
concentrate current research and future development on the one license
I retain.
It may be that Digital Radio threatens to put what's already a fringe
set of frequencies even further out on the fringes. This has squeezed
out grand visions for MF-NAS networking like Radio 2 (
http://en.wikipedia.org/wiki/Radio_2_%28Australian_radio_station%29
) , and even my own networking vision. Instead, we're getting little
guys like 2GW in Sydney - highly concentrated efforts - even where the
format appears mainstream.
The guiding principle appears to be that MF-NAS broadcasts need to be
super-efficient, in terms of both cost and output. That should have
always been obvious, but it's more apparent now than ever.
UCB have recently moved their 1674 kHz license location to Carbrook, a
suburb of Logan City. I suspect that if they activate that one soon,
it might provide us Melbourne learners with some guidance.
...From Justin
Station X
I was on the point that the UK gov gets the shits over the years with
stuff like Radio Luxemburg or any other hi power service coming back
at them. So they deliberatly do it too back.
Reference to Radio Caroline is the current day reference to them
wanting an AM slot on the dial that isn't used in Europe and it's one
of the channels that are supposed to be used on their side of the
ocean. You have the Brits blasting this power over the water back to
Europe.
What the fuck was the whole convention for in the first place? That's
my point!
LBP
> concentrate current research and future development on the one license
> I retain.
>
I would really like to see you put your Mediumwave license on the air
as you're in a great location
for signal propagation looking out from coastal Frankston over Port
Phillip Bay would produce a good signal
into Portarlington, Geelong, Werribee, Point Cook as well as the
Peninsula coastline and into in particular the
coastal paths in the south eastern suburbs of Melbourne and also a
suburban radius of probably 10 ~ 20 km
of your transmitter site if you were using a reasonably efficient
physically short 30 - 50 foot top loaded vertical
with a reasonable ground system i.e. tin roof or ground radials /
counterpoise.
The sea acts as natures own amplifier when it comes to Mediumwave MF
AM signal propagation.
> It may be that Digital Radio threatens to put what's already a fringe
> set of frequencies even further out on the fringes. This has squeezed
> out grand visions for MF-NAS networking like Radio 2 (http://en.wikipedia.org/wiki/Radio_2_%28Australian_radio_station%29
> ) , and even my own networking vision.
Radio 2 was a ambitious plan with a cunning approach - a back door
entry into establishing a commercial radio network without having
to spend millions of dollars on the bidding process of normal
commercial broadcast licenses.
> Instead, we're getting little
> guys like 2GW in Sydney - highly concentrated efforts - even where the
> format appears mainstream.
>
This is a good example of what can be achieved with a Narrowband MF AM
license and making the effort to
try to make it work in a successful manner.
> The guiding principle appears to be that MF-NAS broadcasts need to be
> super-efficient, in terms of both cost and output. That should have
> always been obvious, but it's more apparent now than ever.
>
I agree - try to use your own resources as much as possible. You can
benefit with your station
site location and having the available land to erect a suitable
antenna installation.
> UCB have recently moved their 1674 kHz license location to Carbrook, a
> suburb of Logan City. I suspect that if they activate that one soon,
> it might provide us Melbourne learners with some guidance.
>
I think it's probably best just to get yourself a transmitter and have
someone help you with building
a suitable antenna and then feed your studio output to your FM network
along with your AM transmitter.
LBP
> ...From Justin
atec77
interesting , might
Not saying any more
Personally my experience with digital is all bad , it's expensive it
drops out in the car and sound flat to my ears
I have a very old awa rx and the sounds emanating from it piss all
over anything I can find on the digital medium
--
X-No-Archive: Yes
LBP
radio.
DAB+ and DRM is not what does it for me,
speaking personally here.
The 6 metre band as it sounds like an interesting place to experiment.
vk3ye
"LBP" <privat...@yahoo.com> wrote in message
news:6a3a68fb-e3bb-4466...@f31g2000pri.googlegroups.com...
> One motivation for me divesting MF-NAS licenses last year was to
> concentrate current research and future development on the one license
> I retain.
>
I would really like to see you put your Mediumwave license on the air
as you're in a great location
for signal propagation looking out from coastal Frankston over Port
Phillip Bay would produce a good signal
into Portarlington, Geelong, Werribee, Point Cook as well as the
Peninsula coastline and into in particular the
coastal paths in the south eastern suburbs of Melbourne and also a
suburban radius of probably 10 ~ 20 km
of your transmitter site if you were using a reasonably efficient
physically short 30 - 50 foot top loaded vertical
with a reasonable ground system i.e. tin roof or ground radials /
counterpoise.
Yep. I've tried 3 spots from around there.
All locations would be OK over the bay, but as far as listener
numbers go the trick is to get a good strong signal into the
southern and eastern suburbs.
For this purpose Frankston Park is nothing special.
Mt Eliza though was fantastic in all directions. A site near either the
Daveys or Canadian Bay boat clubs would be ideal.
LBP
>
Pete/YE I know you have the plenty of real experience with Mediumwave
transmissions.
Mt Eliza was especially successful for you in so far as signal reach
and strength.
> All locations would be OK over the bay, but as far as listener
> numbers go the trick is to get a good strong signal into the
> southern and eastern suburbs.
>
> For this purpose Frankston Park is nothing special.
>
The listed transmitter site isn't far from the water according to the
map - but it's not right on the edge either .. approx 490 metres from
tx to beach.
> Mt Eliza though was fantastic in all directions. A site near either the
> Daveys or Canadian Bay boat clubs would be ideal.
Now how would Portarlington compare over Mt Eliza for signal
penetration into Melbourne ?
Station X
I don't know the places where the correct target population lives in
Melbourne so I can only state technical things.
LBP sea water is great for conducting (or not absorbing) the signal as
it travels along the ground as a ground wave. The problem comes when
it hits the beach. Beach sand is seriously the opposite. The longer
the beach the more resistance!
So getting around the bay might work but serious signal punch might be
a different story.
We've had 4KQ move into the City from St Helena Island. 4KQ was great
down here on the Gold Coast it was booming on 693khz. Now forget it!
But in the greater internals of Brisbane it is better! Their aerial is
basically right in the middle of the action. Where as before it was 20
out to sea from most parts of Brissy. Over water!
There was other reasons too like the license changed hands and the new
owners had their own AM site. So why share with someone else and pay
for desiel to be barged over. Short version even 4TAB that is still
there smashes in down here. But yup not so flash right in the guts of
Brissy.
AM masts need to be in the middle of the action. But we know it's
often the outer suburbs that have the mushy land it needs.
vk3ye
> Yep. I've tried 3 spots from around there.
>Now how would Portarlington compare over Mt Eliza for signal
>penetration into Melbourne ?
I reckon it would be excellent. Slightly longer distance but good take-off.
Indented Head looks even better on the map, though for Geelong coverage
Portarlington might still be superior.
LBP
> Indented Head looks even better on the map, though for Geelong coverage
> Portarlington might still be superior.
Pete/YE it would be good if at some stage you can go MF portable about
those locations
(Portarlington and Indented Head) and see what sort of results are
achieved - I know it's an awkward
side of Melbourne as you have to go right around through Geelong to
get there .. I don't think there's
a short cut to that part.
StnX
> sea water is great for conducting (or not absorbing) the signal as
>it travels along the ground as a ground wave. The problem comes when
>it hits the beach. Beach sand is seriously the opposite. The longer
>the beach the more resistance!
>So getting around the bay might work but serious signal punch might be
>a different story.
Pete/Stn X - good points and I guess that's the problem when you have
your transmitter site
right on the edge of the coast getting the signal to go inland behind
and to the sides of you
is still going to be an issue - especially if you're low powered.
Of course if your transmitter was located - as an example - in the
middle of Port Phillip Bay in Melbourne
- then I imagine things would be pretty perfect for getting the signal
out in all directions and hopefully penetrating
sufficiently in land.
The choice of transmitter site is really the key element for effective
signal coverage.
This is one of the benefits of being able to run portable
transmissions - of course for narrowband (MF/VHF NAS) broadcast
licenses
ACMA want fixed positions and you have to really stick to your
registered TX site.
This is an audio program titled "wartime deception" and features
clandestine propaganda radio transmitting stations operating
during wartime often running portable with truck mounted 100 KW
transmitters and telescopic antenna masts attached to the trucks.
This is a very interesting recording and one could use some of the
approaches used back then for portable transmissions today.
Part 1.
http://traffic.libsyn.com/jonathanmarks/WartimeDeceptionPart1.mp3
Part 2.
http://traffic.libsyn.com/jonathanmarks/wartimedeceptionpart2.mp3
atec
>Carbrook is a few minutes drive from here so if they do it might be
>interesting , might Not saying any more..
Here is the assignment details
http://web.acma.gov.au/pls/radcom/site_search.site_lookup?pSITE_ID=139677
view 1674 kHz TX site
BearCave
> I would really like to see you put your Mediumwave license on the air
> as you're in a great location
> for signal propagation looking out from coastal Frankston over Port
> Phillip Bay would produce a good signal
> into Portarlington, Geelong, Werribee, Point Cook as well as the
> Peninsula coastline and into in particular the
> coastal paths in the south eastern suburbs of Melbourne and also a
> suburban radius of probably 10 ~ 20 km
> of your transmitter site if you were using a reasonably efficient
> physically short 30 - 50 foot top loaded vertical
> with a reasonable ground system i.e. tin roof or ground radials /
> counterpoise.
Actually, I spoke with my techie the other day and we're getting
clearer about what's going to be required. Your estimation seems
about right. The 1674 kHz Melbourne signal would possibly be similar
in performance to the 3CW 1629 kHz signal if we benchmark what they
do, Compare this with the 1611 kHz model of broadcasting out in the
western suburbs, which is a very strong signal, but doesn't guide us
towards the the cost:output balance we seek.
> The sea acts as natures own amplifier when it comes to Mediumwave MF
> AM signal propagation.
Which is what makes the 1629 kHz signal the one to be guided by.
> I think it's probably best just to get yourself a transmitter and have
> someone help you with building
> a suitable antenna and then feed your studio output to your FM network
> along with your AM transmitter.
If we realise our ambition, the AM broadcast will vary from the FM
one. If we don't vary it, in terms of audience segmentation
variables, we'll miss opportunities. Vary it too much and the whole
thing potentially becomes pie in the sky as far as management goes.
I wish I could tell you exactly when this might happen, but I can at
least confirm that two of three MF-NAS licenses were divested in 2010
and the one left is what's considered the most probable to happen.
...From Justin
atec77
pipe real gain can be had
--
X-No-Archive: Yes