Speaking of BBC Radio ...
Morris Keesan
I
notice that Radio 2 describe themselves as "88 to 91 FM". How does that
work?
Do they just blast their signal across all frequencies in that range? Or
do they
have different frequencies within that range, coming from different
transmitters
across the country, with listeners having to search for the frequency that
works
best in their location?
Personally, I have presets on my car radio for 4 different stations in
that frequency range.
--
Morris Keesan -- mke...@post.harvard.edu
Colette Reap
>I've recently added a few Radio 2 programmes to my listening schedule, and
>I notice that Radio 2 describe themselves as "88 to 91 FM". How does that
>work?
>[...] do they have different frequencies within that range, coming from different
>transmitters across the country, with listeners having to search for the frequency that
>works best in their location?
Sort of. Here's a page that'll tell you probably more than you'll ever
want to know about how the BBC use their radio frequencies :-)
Dave Whiley
> I've recently added a few Radio 2 programmes to my listening schedule,
> and I
> notice that Radio 2 describe themselves as "88 to 91 FM". How does that
> work?
> Do they just blast their signal across all frequencies in that range?
> Or do they
> have different frequencies within that range, coming from different
> transmitters
> across the country, with listeners having to search for the frequency
> that works
> best in their location?
The latter, although with VHF having little or no over-the-horizon
capability, there's often only one frequency that works in any
particular location.
When car radios had to be tuned by turning a knob, most stations
broadcast on both AM and FM, so I usually set up the stations on AM and
traded clarity for less frequent tuning. By the time duplication
stopped, I had a radio with search buttons, so it was just a case of
remembering whether I was at the low end of the frequency range and
needed to search upwards, or at the high end and needed to search
downwards. Or in the middle, in which case it was anyone's guess.
Nowadays, the radio retunes itself automatically, and by and large I
don't even notice when it does.
--
Dave
not-me should be djw001 and there's no need for any wossname
Paul Dormer
not...@WOSSNAMEfreeserve.co.uk (Dave Whiley) wrote:
>
> The latter, although with VHF having little or no over-the-horizon
> capability, there's often only one frequency that works in any
> particular location.
I presume part of the reason it's done this way in the UK is that if two
adjacent transmitters were transmitting an identical signal on identical
frequencies, where the transmitter coverages overlap you'd get
interference effects.
Andrew Plotkin
You get the same thing driving across rural New England, although they
spell out all the local frequencies. "This is WYOG, broadcasting on
88.1 in Arkham, 88.7 Innsmouth, 90.3 Naaquatonic..."
--Z
--
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
*
Keith F. Lynch
> I presume part of the reason it's done this way in the UK is that if
> two adjacent transmitters were transmitting an identical signal on
> identical frequencies, where the transmitter coverages overlap you'd
> get interference effects.
Not if they're tuned to *exactly* the same frequency, as WWV and WWVH
are. (Well, okay, nothing is exact. But to within a few nanohertz.)
--
Keith F. Lynch - http://keithlynch.net/
Please see http://keithlynch.net/email.html before emailing me.
Paul Dormer
Lynch) wrote:
>
> Paul Dormer <p...@pauldormer.cix.co.uk> wrote:
> > I presume part of the reason it's done this way in the UK is that if
> > two adjacent transmitters were transmitting an identical signal on
> > identical frequencies, where the transmitter coverages overlap you'd
> > get interference effects.
>
> Not if they're tuned to *exactly* the same frequency, as WWV and WWVH
> are. (Well, okay, nothing is exact. But to within a few nanohertz.)
Surely you'd get fringing, like in a two slit experiment.
Wavelength of 100Mhz is 3 metres. So every metre or so, you'd get a dead
spot.
Keith F. Lynch
Only if the signal strengths were exactly the same where you were, and
only if your antenna was entirely in that dead spot. In practice,
it's just as likely to happen with a single station and its reflection
off some wall or building. If it happens, the solution is to adjust
the antenna by a few centimeters.
If two signals *almost* cancel out, your receiver's automatic gain
control compensates -- unless the total signal is weaker than the
receiver's internal noise, which is unlikely.
If the two signals differ in freqency by one nanohertz, the dead zone
will move by about one inch per year.
Kip Williams
> Here, Paul Dormer <p...@pauldormer.cix.co.uk> wrote:
>> In article <5B5Hm.2069$X77....@newsfe24.iad>,
>> not...@WOSSNAMEfreeserve.co.uk (Dave Whiley) wrote:
>>
>>> The latter, although with VHF having little or no over-the-horizon
>>> capability, there's often only one frequency that works in any
>>> particular location.
>> I presume part of the reason it's done this way in the UK is that if two
>> adjacent transmitters were transmitting an identical signal on identical
>> frequencies, where the transmitter coverages overlap you'd get
>> interference effects.
>
> You get the same thing driving across rural New England, although they
> spell out all the local frequencies. "This is WYOG, broadcasting on
> 88.1 in Arkham, 88.7 Innsmouth, 90.3 Naaquatonic..."
Back when Denver's KVOD had to compete with a loud country station on an
adjacent frequency (the FCC claimed we couldn't get KVOD anyway, so we
had nothing to complain about), so many repeaters sprang up that it
seemed to take about a minute for an announcer to name them all.
Kip W
Dave Whiley
I would assume so. I should really have qualified what I said about the
o-t-h capability of VHF with "normally". Given the right weather
conditions, co-channel interference does affect the signal quality
(there's a stretch of road near me where, given the right weather, Radio
4 disappears completely for a mile or so).
I remember when co-channel interference was called "foreign"
interference, thereby implying that it was All Their Fault.
Keith F. Lynch
> If the two signals differ in freqency by one nanohertz, the dead
> zone will move by about one inch per year.
To clarify, I'm assuming the two stations on the same frequency are
correcting for general relativity. This can be done by simply using
some common external frequency reference, such as WWV.
Without such correction, two absolutely identical perfect 100 MHz
transmitters whose altitude differed by 100 meters would differ in
frequency by about one microhertz, i.e. about one cycle every week
or two.
(It's the transmitter's altitude, or more properly the transmitter's
oscillator's clock's altitude, which is important, not the transmitting
antenna's altitude. Signals get red-shifted as they go up the cable
or waveguide to the antenna.)
Paul Dormer
Lynch) wrote:
>
> If two signals *almost* cancel out, your receiver's automatic gain
> control compensates -- unless the total signal is weaker than the
> receiver's internal noise, which is unlikely.
So, any other suggestion as to why the BBC should have about a 3MHz
spread for each of their stations across the country? (That is, for each
station, the frequency for the local transmitter is somewhere within a
3MHz range.)
Certainly, here in Guildford I can pick up Radio 3 on two different
frequencies, and on at least one occasion, when one transmitter had a
fault, I could re-tune and still listen. If all the transmitters used
the same frequency, I wouldn't have to retune.
My bedside radio is FM, my two downstairs radios are DAB. When a year or
two ago I woke up to find a problem on the usual Radio 3 frequency and
had to retune, I also found I was having problems with my DAB radios
after I got up.
Paul Dormer
not...@WOSSNAMEfreeserve.co.uk (Dave Whiley) wrote:
>
> I remember when co-channel interference was called "foreign"
> interference, thereby implying that it was All Their Fault.
Back in the sixties, I used to listen to Radio 3 on AM and listening to
the Proms in the summer (when foreign interference seemed to be stronger)
I'd hear Radio Warsaw quite clearly in the background. Got to know the
Polish national anthem quite well, as it would be broadcast each night at
20:00 UK time.
Morris Keesan
wrote:
Thank you. More than I needed to know, but very informative.
Is it the case that no other (non-BBC) stations in the UK are allowed to
use any of the frequencies in the ranges allocated to the BBC?
How sparse is the UK radio population, anyway? In the greater Boston
area, our spectrum is so densely populated that I have trouble finding
a clear frequency for using my little FM transmitter that lets me listen
to an MP3 player on my car radio.
Paul Dormer
(Morris Keesan) wrote:
>
> Is it the case that no other (non-BBC) stations in the UK are allowed
to
> use any of the frequencies in the ranges allocated to the BBC?
> How sparse is the UK radio population, anyway? In the greater Boston
> area, our spectrum is so densely populated that I have trouble finding
> a clear frequency for using my little FM transmitter that lets me
listen
> to an MP3 player on my car radio.
>
The Radio Times, originally the BBC listings magazine, has a page of
radio frequencies for BBC and non-BBC stations. There are only five
national radio stations listed that broadcast on FM - BBC Radios 1-4 and
Classic FM. Classic FM also has a range given - 99.9-101.9
For local stations, I get the Radio Times for the London/Anglia/Midlands
area so it only lists stations for those areas. For BBC local radio,
there seems to be one frequency per locale. So, here in Guildford I
should get Sussex and Surrey radio on 104.6 but in Brighton it's on 95.3.
And then there are about 20-30 independent stations listed, but not all
are available in all areas. For instance, Galaxy radio is available only
in the Birmingham area on 102.2, but Heart radio seems to be available
all over the south east on a whole slew of frequencies, ranging from 96.1
in Ashford to 106.2 in London.
It was announced recently that by 2017, FM will be for local stations
only, and all national stations will be DAB only.
Keith F. Lynch
> It was announced recently that by 2017, FM will be for local
> stations only, and all national stations will be DAB only.
Did they ever get DAB to work right, or does it still sound like
boiling mud?
Andy Leighton
>> It was announced recently that by 2017, FM will be for local
>> stations only, and all national stations will be DAB only.
>
> Did they ever get DAB to work right, or does it still sound like
> boiling mud?
It works absolutely fine for me and always has. Better sound quality
than FM.
--
Andy Leighton => an...@azaal.plus.com
"The Lord is my shepherd, but we still lost the sheep dog trials"
- Robert Rankin, _They Came And Ate Us_
Paul Dormer
(Andy Leighton) wrote:
>
> On Thu, 5 Nov 2009 02:11:16 +0000 (UTC),
> Keith F. Lynch <k...@KeithLynch.net> wrote:
> > Paul Dormer <p...@pauldormer.cix.co.uk> wrote:
> >> It was announced recently that by 2017, FM will be for local
> >> stations only, and all national stations will be DAB only.
> >
> > Did they ever get DAB to work right, or does it still sound like
> > boiling mud?
>
> It works absolutely fine for me and always has. Better sound
> quality than FM.
Indeed, yes. I actually bought a small DAB receiver for the kitchen
radio as I kept on picking up a pirate station on a frequency near Radio
3. Then I found that there was a noticeable time delay between that and
the FM tuner on my stereo, so I got a good quality DAB tuner for that and
the sound is excellent - and no interference.
Occasionally there have been transmitter faults which has superimposed a
burbling on all transmissions, but that has been corrected quickly every
time.
And a few years ago, the BBC tried cost cutting by reducing the bit rate
on Radio 3. No one should notice, said the engineers. Everyone did, and
the old bit rate was re-instated. Ironically, it was in the month of
July, just before the Prom concerts were starting, and Radio 3 was
running an advertising campaign telling people to listen to the Proms in
sparkling digital stereo on DAB radio.
Colette Reap
>On Thu, 5 Nov 2009 02:11:16 +0000 (UTC),
> Keith F. Lynch <k...@KeithLynch.net> wrote:
>> Paul Dormer <p...@pauldormer.cix.co.uk> wrote:
>>> It was announced recently that by 2017, FM will be for local
>>> stations only, and all national stations will be DAB only.
>>
>> Did they ever get DAB to work right, or does it still sound like
>> boiling mud?
>
>It works absolutely fine for me and always has. Better sound quality
>than FM.
Same here.
--
Colette
Daniel R. Reitman
<erky...@eblong.com> wrote:
>You get the same thing driving across rural New England, although they
>spell out all the local frequencies. "This is WYOG, broadcasting on
>88.1 in Arkham, 88.7 Innsmouth, 90.3 Naaquatonic..."
I'm still waiting for Oregon Public Broadcasting to set up a station
in Ether.
Dan, ad nauseam
Lowell Gilbert
They'd get a donation from me. And I haven't been in radio range of
Oregon in about three decades.