Radio 4 LW quality
Ian Fleming
The sound quality is now 'tinny'/sybillant harsh compared to other AM
transmissions.I have tried it on a number of my old valve sets and more
modern items.
Does anyone have an explanation ?
It sounds almost as if the incoming audio has gone 'one-legged' and
someone has cranked the gain up to compensate on a 500kW TX!
I am also a DAB listener,this is excellent generally,though there are
quality issues describedin this group.
Gareth,I liked the quiz,it brought a smile or two ,well done.
Ian
Dave Plowman
<ifleming-301...@host213-122-198-227.in-addr.btopenworld.com>,
Ian Fleming <ifle...@btopenworld.com> wrote:
> I,m probably the only one left listening to this,as a BOF.
> The sound quality is now 'tinny'/sybillant harsh compared to other AM
> transmissions.I have tried it on a number of my old valve sets and more
> modern items.
> Does anyone have an explanation ?
Having listened to it on the Quad AM 3, I'd agree it sounds more 'tinny'
than R4 on medium wave. I'd guess it's to do with the processor. Sounds a
bit like a rising characteristic from about 2-4k - perhaps about 6dB per
octave? It didn't sound *too* bad on the speech I listened to, but might
well be a different matter on say cricket with lots of FX.
--
*If at first you don't succeed, then skydiving definitely isn't for you *
Dave Plowman dave....@argonet.co.uk London SW 12
RIP Acorn
tony sayer
addr.btopenworld.com>, Ian Fleming <ifle...@btopenworld.com> writes
Perhaps their using a DAB RX to drive the longwave one. After all AM
isn't that much better than Radio 4 DAB...
--
Tony Sayer
Stephen
"Ian Fleming" <ifle...@btopenworld.com> wrote in message
news:ifleming-301...@host213-122-198-227.in-addr.btopenworld.com..
.
I think they are clipping the high frequencies. It sounds distorted. I've
tried listening on various radios. The high frequencies don't sound too bad
on the radios with wider bandwidth, but on the narrower bandwidth ones it
definitely sounds wrong. Instead of speech sibilants practically
disappearing, as they do on with any other LW station, there's a distorted
low frequency mush accompanying each "s" and "sh". It's been like this on
and off for months. I guess this is less likely to be a problem with a
program feed, and more likely to be someone's idea of making Long Wave sound
less muffled - by overdriving the treble so much that it clips. There should
be a better way of doing this, like turning up the treble more before the
compressor. But I wonder if there's another problem. Can they actually get
100% modulation out of this transmitter at 4 kHz? Perhaps the aerial
bandwidth isn't wide enough, or a transmitter mod is needed. All I know is
that France Inter on 162 sounds much louder and clearer than the BBC, and
they seem to be able to achieve more treble without distortion.
Dave Plowman
Stephen <ste...@junkmailblocker.sptv.demon.co.uk> wrote:
> I think they are clipping the high frequencies. It sounds distorted.
> I've tried listening on various radios. The high frequencies don't sound
> too bad on the radios with wider bandwidth, but on the narrower
> bandwidth ones it definitely sounds wrong. Instead of speech sibilants
> practically disappearing, as they do on with any other LW station,
> there's a distorted low frequency mush accompanying each "s" and "sh"
Just had another listen on the AM3, and I wouldn't agree. Could well be a
design problem on the receiver - most are rubbish.
--
*I used up all my sick days so I called in dead
Ian Fleming
<ste...@junkmailblocker.sptv.demon.co.uk> wrote:
> I think they are clipping the high frequencies. It sounds distorted. I've
> tried listening on various radios. The high frequencies don't sound too bad
> on the radios with wider bandwidth, but on the narrower bandwidth ones it
> definitely sounds wrong. Instead of speech sibilants practically
> disappearing, as they do on with any other LW station, there's a distorted
> low frequency mush accompanying each "s" and "sh". It's been like this on
> and off for months. I guess this is less likely to be a problem with a
> program feed, and more likely to be someone's idea of making Long Wave sound
> less muffled - by overdriving the treble so much that it clips. There should
> be a better way of doing this, like turning up the treble more before the
> compressor. But I wonder if there's another problem. Can they actually get
> 100% modulation out of this transmitter at 4 kHz? Perhaps the aerial
> bandwidth isn't wide enough, or a transmitter mod is needed. All I know is
> that France Inter on 162 sounds much louder and clearer than the BBC, and
> they seem to be able to achieve more treble without distortion.
I agree the French stations sound so much better.
I first noticed it on my older valve radios,I fix them for fun?,but I will
do some listening tests on some of my other more modern RXs,I dont have an
AM3 but do have the old valve Quad AM 2? tuner with the wider bandwidth.
I sold may SW77 etc on Ebay,too fiddly to use on a regular basis.
All my valve RXs show up the problem,they used to be fine,it has changed
in the past 6 months.
I have a nice Gurndig I will try.
Ian
Dave Plowman
Ian Fleming <ifle...@btopenworld.com> wrote:
> I dont have an
> AM3 but do have the old valve Quad AM 2? tuner with the wider bandwidth.
I *think* they are identical, apart from the built in power supply.
I had another play today. LW is definitely 'brighter' sounding than R4 MW.
But I wouldn't say it's distorted - anymore than any other AM transmission.
--
*Why can't women put on mascara with their mouth closed?
Stephen
news:4bafcb52b9...@argonet.co.uk...
>
> I had another play today. LW is definitely 'brighter' sounding than R4 MW.
> But I wouldn't say it's distorted - anymore than any other AM transmission.
>
I think it's the R4 MW which is at fault. If you're in London and comparing
720kHz (Radio 4) with 909kHz (5 Live) you'll hear that 5 Live sounds bright and
clear up and, by comparison, 4 sounds dull and flat and doesn't ride level
changes very well - it's almost like they've forgotten to put the processor in
circuit. The BBC normally gets these things spot on.
charles.hope
Are you sure its R4 LW at fault? I suspect the quality of the receiver.
Dave Plowman
charles.hope <charle...@argonet.co.uk> wrote:
> Are you sure its R4 LW at fault? I suspect the quality of the receiver.
There's certainly a big difference between R4 MW and LW on my Quad AM3
which isn't bandwidth limited. I'd have expected LW to have a slightly
narrower bandwidth than MW, but the reverse seems to be the case.
--
*Filthy stinking rich -- well, two out of three ain't bad
Ian Fleming
OK,narrow bandwidth,splashy ss's etc.
My Grundig YB 510 was also splashy,an old PYE battery vavle set I have
is also OK.I agree that it is still brighter than R5L,I cannot get
good R4 MW in Bath.
I do not remember this problem about 6 months ago.
Dave Plowman <dave....@argonet.co.uk> wrote in message news:<4bb0468637...@argonet.co.uk>...
Dave Plowman
Ian Fleming <ifle...@btopenworld.com> wrote:
> I certainly found that R4 LW on my Quad AM2 ,wide bandwidth setting
> OK,narrow bandwidth,splashy ss's etc.
I'm pretty certain the narrow position on the Quad introduces a degree of
mid range lift to improve clarity. I've got the book somewhere...
> My Grundig YB 510 was also splashy,an old PYE battery vavle set I have
> is also OK.I agree that it is still brighter than R5L,I cannot get
> good R4 MW in Bath.
> I do not remember this problem about 6 months ago.
I stopped using LW regularly when the world service appeared on FM after
R4 closedown, and that was quite some time ago.
I could easily burn a CD of R4 MW and LW as heard in the London area if
it would help.
--
*Sleep with a photographer and watch things develop
Stephen
> I certainly found that R4 LW on my Quad AM2 ,wide bandwidth setting
> OK,narrow bandwidth,splashy ss's etc.
> My Grundig YB 510 was also splashy,an old PYE battery vavle set I have
> is also OK.I agree that it is still brighter than R5L,I cannot get
> good R4 MW in Bath.
> I do not remember this problem about 6 months ago.
>
The London Radio 4 MW transmitter moved last year from Lots Road in Chelsea to
Crystal Palace. Perhaps the problem started then.
The main Droitwich signal on LW should boom into Bath so a MW filler is not
necessary there. You must be picking up out-of-area signal.
Stephen
"Stephen" <nos...@nospam.demon.co.uk> wrote in message
news:avcivf$2ad$1$8302...@news.demon.co.uk...
> "Ian Fleming" <ifle...@btopenworld.com> wrote in message
> news:6f1e5574.03010...@posting.google.com...
> > I certainly found that R4 LW on my Quad AM2 ,wide bandwidth setting
> > OK,narrow bandwidth,splashy ss's etc.
> > My Grundig YB 510 was also splashy,an old PYE battery vavle set I have
> > is also OK.I agree that it is still brighter than R5L,I cannot get
> > good R4 MW in Bath.
> > I do not remember this problem about 6 months ago.
> >
>
> The London Radio 4 MW transmitter moved last year from Lots Road in
> Chelsea to Crystal Palace. Perhaps the problem started then.
I'm in London & it was just as bad before the move. It always sounded like
mud. Now it's even worse for me, because Crystal Palace is much farther
away. My signals are attenuated by the building's steel frame, and then have
to contend with a dozen TV sets and other equipment with switch mode power
supplies in all the surrounding flats, but my reception conditions are
typical in London, and Radio 4 MW should be designed to deal with them,
since it was specifically meant as an alternative to LW because of the poor
reception conditions in London. Only the strongest and most heavily
processed stations like Radio 5 and Virgin can make themselves heard
properly here, and Radio 4 MW should do likewise. It is completely
inadequate as it is, provides me with reception no less bad than LW, and the
mild audio processing does nothing to help matters.
If someone responsible came to my flat and heard just how bad reception is -
bang in the middle of this station's supposed target area - they would
realise that there is simply no point continuing to operate the station as
it is. If they really want this station to do it's job, they should use much
more power, drive it harder into the limiters, and boost the treble. I guess
it would need at least 10 kW to bring it up to the level of other signals
that DO work in Central London.
Stephen
news:avh6pd$lqc$1$8302...@news.demon.co.uk...
> It is completely
> inadequate as it is, provides me with reception no less bad than LW
Given this, why not put the BBC Asian Network on 720kHz in London instead? That
would seem a useful outlet for the service which is only available on digital
otherwise in the capital.
Stephen
Sunrise Radio. But it would still need more power, specially so because
Sunrise uses the old BBC Radio London transmitter which is 50 kW. Also,
since it's Radio 4, they'd probably be very reluctant to switch it off
because it may be part of an emergency broadcast network. FM and digital
work ok, but if they really want to continue to use MW in London they need a
much more flexible attitude towards allocating frequencies, and using enough
power to cut through the interference. What's really needed is a new
frequency for a station like Asian Network (990 is free), and a minimum of
10kW for all the stations that are presently trying to cover London with too
little power, like Radio 4, Country 1035, and Premier. Another problem is
World Service on 648. They probably think this is ok, since no doubt you can
get reasonable reception in a suburban semi, but I can't listen to it. In
this case a "quasi-synchronous" 10 kW filler at Crystal Palace on the same
frequency of 648 would do the job.
Mark Carver
"Stephen" <ste...@junkmailblocker.sptv.demon.co.uk> wrote in message
news:avh6pd$lqc$1$8302...@news.demon.co.uk...
>
> mud. Now it's even worse for me, because Crystal Palace is much farther
> away. My signals are attenuated by the building's steel frame, and then have
> to contend with a dozen TV sets and other equipment with switch mode power
> supplies in all the surrounding flats, but my reception conditions are
> typical in London, and Radio 4 MW should be designed to deal with them,
> since it was specifically meant as an alternative to LW because of the poor
> reception conditions in London.
Going back a few years to when the BBC Light Programme occupied 200kHz,
was 1214 kHz not added to enhance reception in urban areas? Therefore the 'filler'
for London was that service at high power from Brookmans Park.
Of course in 1967 1214kHz (aka 247m) was hijacked to provide Radio 1.
ISTR the Beeb established 720kHz from Lots Road shortly after the great MF/LF frequency
changes of Nov 78 after complaints from R4 listeners in London that LW was inadequate.
But as pointed out, that transmitter didn't have much poke, and at the new CP location even less .
So the Beeb haven't really properly replaced the fill in service they removed 35 years ago.
CJBanister
output to maximise the readability of the program.
"Mark Carver" <markc...@onetel.net.uk> wrote in message
news:avjd2l$gf160$1...@ID-75131.news.dfncis.de...
charles.hope
Paul Martin <p...@zetnet.net> wrote:
> In article <avi27r$otl$1$8302...@news.demon.co.uk>,
> Stephen wrote:
> > little power, like Radio 4, Country 1035, and Premier. Another problem
> > is World Service on 648. They probably think this is ok, since no
> > doubt you can get reasonable reception in a suburban semi, but I can't
> > listen to it. In
> 648kHz isn't for UK reception. It uses a directional aerial array
> nowadays.
Absolutely true, but "nowadays" = "for the last 20 years". The
transmitter moved from Crowborough, Sussex, to Orford Ness, Suffolk.
Despite the directional aerial, there is a service level signal to the
east of a line extending from the Wash via Reading to Brighton. I
remember measuring it!
--
Using a RISC PC with RISC OS4
No...@m.here.please
On Thu, 9 Jan 2003, charles.hope wrote:
> Absolutely true, but "nowadays" = "for the last 20 years". The
> transmitter moved from Crowborough, Sussex, to Orford Ness, Suffolk.
> Despite the directional aerial, there is a service level signal to the
> east of a line extending from the Wash via Reading to Brighton. I
> remember measuring it!
I understand that the transmitter in question was the "Aspidistra" unit
from World War 2? Is there any truth to it being relocated to Orford Ness
- seems unlikely given the then age of the unit? If true - Is the original
transmitter still in use or even still in existance?
Richard Lamont
Many of the historic 'Aspidistra' transmitter buildings at Crowborough
still exist, in various states of repair, but the equipment is all long
gone. I had a good look round the site, which is now owned by Sussex
Police and used as a training centre, last year.
What's left includes a number of enormous transmitter halls, cooling
ponds, glass feedthrough insulators and a few spectacular art deco
interior features.
--
Richard Lamont
ric...@stonix.demon.co.uk
Laurence Taylor
p...@zetnet.net "Paul Martin" writes:
-> 648kHz isn't for UK reception. It uses a directional aerial array
-> nowadays.
Then why is it on DAB and DTV?
rgds
LAurence
-------------------------------------------------------------------
Wicked Witch parking only - violators will be toad
===================================================================
->> This message produced entirely in DOS <<-
charles.hope
<No...@m.here.please> wrote:
I alwas understood that the new installation used new transmitters. This
is fairly likely since for the first few weeks of Orfordness' life, the
signals came from Crowborough at times while adjustment were made at
Orfordness. They'd have had difficulty in moving the transmitter between
the sites in under a minute!
charles.hope
Laurence Taylor <laur...@iapetus.demon.co.uk> wrote:
> In article <slrnb1p8...@laptop.nowster.org.uk>
> p...@zetnet.net "Paul Martin" writes:
> -> 648kHz isn't for UK reception. It uses a directional aerial array
> -> nowadays.
> Then why is it on DAB and DTV?
to make the World Service available in the UK, of course.
Brian D
charles.hope <charle...@argonet.co.uk> wrote:
I'm not sure if they were /new/ new, I suspect they were F&CO specials that
had been touted round the empire as it shrank. Orfordness and Crowborough
together with some overseas stations were until fairly recently directly
owned by the government, not by the BBC (now owned by Merlin/Cron Castle).
The original wartime 600kw Crowborough transmitter was in use for long after
the war, supposedly at 100kw as per international agreement, but when I lived
in Sussex, it was too strong to have been 100kw. When originally built it was
in competition with Ottringham as the most powerful broadcast transmitter,
the Ottringham ones supposedly being 800kw, but from what was rumoured they
never managed the full power of the system to the aerial.
The Ottringham transmitters were mothnballed in the 50s and installed in the
main building at Droitwich in the 60s (to replace a similar vintage system
for light programme, and the original national and regional Txs then used
for the Home service. This remained in service until the 80s when it was
replaced by the current unattended (and more efficient) transmitters.
--
Brian D
No...@m.here.please
On Fri, 10 Jan 2003, Brian D wrote:
> The original wartime 600kw Crowborough transmitter was in use for long after
> the war, supposedly at 100kw as per international agreement, but when I lived
> in Sussex, it was too strong to have been 100kw. When originally built it was
> in competition with Ottringham as the most powerful broadcast transmitter,
> the Ottringham ones supposedly being 800kw, but from what was rumoured they
> never managed the full power of the system to the aerial.
Thanks for everyone's feedback - most interesting.
The current Offordness transmitters can be seen here:-
http://www.radionationaal.nl/archive/merlin/page01.htm
I wasn't aware that they also provided the 1269 Khz signal for Radio
Nationaal until I stumbled onto that site. It's an odd situation that
another countries domestic service should come from abroad.
It's sad that the preservation of the Aspidistra transmitter facility was
not considered worthwhile. What with this and the studios at Ally Pally
being left to rot, there seems little regard for the preservation of our
broadcasting heritage.
Mark Carver
"charles.hope" <charle...@argonet.co.uk> wrote in message news:4bb2bda44cc...@argonet.co.uk...
> > -> 648kHz isn't for UK reception. It uses a directional aerial array
> > -> nowadays.
>
> > Then why is it on DAB and DTV?
>
> to make the World Service available in the UK, of course.
I don't follow the logic. BBC WS Radio is not a service aimed at the UK, and
its (original) programming is not financed from the licence fee.
It's hogging bandwidth on DAB, and to a lesser extent on DTT, that could be used
for the domestic services that we do pay for.
Not an issue with D-Sat on 28.2E, and indeed that helps to provide coverage to the rest of Europe.
Mike Christieson
that prior to Orfordness both 1088kHz (before the frequency shift) and
1295kHz came from Crowbrough along with 809kHz at lunchtime in French.
1088 and 809 was from the Aspidistra unit (Aspi1) which was frequency
changed twice daily. 1088 was 600kW and 809 was 400kW, both to a three
element array (one driven and two parasitics). 1295 was 500kW from an
FCO designed pair of Doherty units (Aspi2) feeding a six element array.
There were also two hf 100kW units (Aspi3 and Aspi4) operating.
All audio was on copper music lines from Bush.
Orforness was initially a 50kW Continental Electronics tx during the day
with Crowborough on at night. I cannot remember at what stage 1088
became 648 but by that time Orfordness had a new tx and another tx on
1296. I think Aspi2 was moved from Crowborough one 250kW unit at a time.
Aspi1 remained at Crowborough as a standby until sometime in the
eighties when it was scrapped - including its neo-odeon cinema
underground building with marble staircase. The whole site closed in the
eighties. I had long left by then.
I am not sure what the configuration is now, I am sure someone from
merlin can tell us but at least one of the tx is Telefunken.
--
Mike Christieson
Dave Plowman
Mark Carver <markc...@onetel.net.uk> wrote:
> I don't follow the logic. BBC WS Radio is not a service aimed at the UK,
> and its (original) programming is not financed from the licence fee.
> It's hogging bandwidth on DAB, and to a lesser extent on DTT, that could
> be used for the domestic services that we do pay for.
Wot - yet another identical pop station?
--
*I'm out of my mind, but feel free to leave a message.
Mark Carver
"Dave Plowman" <dave....@argonet.co.uk> wrote in message news:4bb316bffb...@argonet.co.uk...
> In article <avoou7$i00hn$1...@ID-75131.news.dfncis.de>,
> Mark Carver <markc...@onetel.net.uk> wrote:
> > I don't follow the logic. BBC WS Radio is not a service aimed at the UK,
> > and its (original) programming is not financed from the licence fee.
>
> > It's hogging bandwidth on DAB, and to a lesser extent on DTT, that could
> > be used for the domestic services that we do pay for.
>
> Wot - yet another identical pop station?
Hopefully not. I was thinking more in terms of BBC7 in stereo etc.
Dave Plowman
Mark Carver <markc...@onetel.net.uk> wrote:
> Hopefully not. I was thinking more in terms of BBC7 in stereo etc.
Many of the progs broadcast on that weren't made in stereo.
--
*Organized Crime Is Alive And Well; It's Called Auto Insurance. *
Ashley Booth
mi...@aspidistra1.demon.co.uk put fingers to keys and typed.....
Interesting links:
http://www.subbrit.org.uk/rsg/sites/c/crowborough/
Ashley
http://www.qsl.net/g0crw/Special%20Events/Aspidistra3pics.htm
Brian D
No...@m.here.please wrote:
[snip]
> Thanks for everyone's feedback - most interesting.
>
> The current Offordness transmitters can be seen here:-
> http://www.radionationaal.nl/archive/merlin/page01.htm
>
> I wasn't aware that they also provided the 1269 Khz signal for Radio
> Nationaal until I stumbled onto that site. It's an odd situation that
> another countries domestic service should come from abroad.
An Ideal site for MF to the continental seaboard, a sea path offers the least
atenuation of ground wave signals, hence the success of the seabourne pirate
stations running little power int what would (on land be very inefficient
aerials.
Sea path was used by the BBC for domestic MF in the location of Start point
for the south coast, Washford for South Wales and Burghead for the Moray
Firth area.
>
> It's sad that the preservation of the Aspidistra transmitter facility was
> not considered worthwhile. What with this and the studios at Ally Pally
> being left to rot, there seems little regard for the preservation of our
> broadcasting heritage.
>
Very true, Ive seen a lot of broadcast history go in the skip over the years.
--
Brian D
Brian D
Ashley Booth <ne...@snglinks.comremove> wrote:
[snip]
> Interesting links:
>
> http://www.subbrit.org.uk/rsg/sites/c/crowborough/
>
> Ashley
>
> http://www.qsl.net/g0crw/Special%20Events/Aspidistra3pics.htm
Google also brought up
<http://www.subbrit.org.uk/rsg/sites/o/ottringham/>
RSG: Sites: BBC Ottringham
--
Brian D
Brian D
Mike Christieson <mi...@aspidistra1.demon.co.uk> wrote:
> I was on shift at Crowborough in the mid seventies and the situation was
> that prior to Orfordness both 1088kHz (before the frequency shift) and
> 1295kHz came from Crowbrough along with 809kHz at lunchtime in French.
> 1088 and 809 was from the Aspidistra unit (Aspi1) which was frequency
> changed twice daily. 1088 was 600kW and 809 was 400kW, both to a three
> element array (one driven and two parasitics). 1295 was 500kW from an
> FCO designed pair of Doherty units (Aspi2) feeding a six element array.
> There were also two hf 100kW units (Aspi3 and Aspi4) operating.
That fits in very well with my thoughts on the site.
>
> All audio was on copper music lines from Bush.
>
> Orforness was initially a 50kW Continental Electronics tx during the day
> with Crowborough on at night. I cannot remember at what stage 1088
> became 648
October (or was it November) 1978 when all the European MF stations were
supposed to change to multiples of 9khz.
> but by that time Orfordness had a new tx and another tx on 1296. I think
> Aspi2 was moved from Crowborough one 250kW unit at a time. Aspi1 remained
> at Crowborough as a standby until sometime in the eighties when it was
> scrapped - including its neo-odeon cinema underground building with marble
> staircase. The whole site closed in the eighties. I had long left by then.
>
I can remember in the late 60s old gear from OSE8 being sent to ASP as
spares. It would have been as old as the original kit.
Around then, when the bbc wartime Tx overseas extensions started to be called
by their real names I tried to work out where all the OSEs were.
I concluded:
1 Daventry Extension
2 Start Point a SWB 18 and the Domestic TX converted to
75M band at night.
3 Rempisham 6 hf txs, not sure what? 50kw?
4 Droitwich extension, (used from after the war for 200KHZ until replaced by
the ex Ottringham TXs. carried (amongst others( 400kw to a four element
curtain (suspended between the 700' masts) on 247m in German, It fell down
one night with the TX on and all the natives thought paratroopers had landed!
5 Ottringham 4x 200kw MF and LF near Hull
6 Burghead (or westerglen) carrying Norwegian.
7 Lisnagarvey (like Start Point a marconi SWB 18 diverted from an export
order).
8 Skelton A 6x SWB18 100kw
9 Skelton B 6x dual channel ST&C CS8 120KW
10 Wooferton 6 x dual channel RCA 50kw (the second channel empty, reputedly
sunk by U boat in Atlantic).
Can anyone confirm or expand on this?
--
Brian D
charles.hope
Brian D <brian...@lycos.co.uk> wrote:
> Around then, when the bbc wartime Tx overseas extensions started to be
> called by their real names I tried to work out where all the OSEs were.
> I concluded:
but not quite right, according to Pawley.
> 1 Daventry Extension
Senders 4-7
> 2 Start Point a SWB 18 and the Domestic TX converted to
> 75M band at night.
Daventry senders 8-11
> 3 Rempisham 6 hf txs, not sure what? 50kw?
Rampisham (Dorset) Senders 31-34
> 4 Droitwich extension, (used from after the war for 200KHZ until
> replaced by the ex Ottringham TXs. carried (amongst others( 400kw to a
> four element curtain (suspended between the 700' masts) on 247m in
> German, It fell down one night with the TX on and all the natives
> thought paratroopers had landed!
Start Point Sender 22
> 5 Ottringham 4x 200kw MF and LF near Hull
Correct
> 6 Burghead (or westerglen) carrying Norwegian.
Droitwich mf
> 7 Lisnagarvey (like Start Point a marconi SWB 18 diverted from an export
> order).
Sender 51
> 8 Skelton A 6x SWB18 100kw
> 9 Skelton B 6x dual channel ST&C CS8 120KW
Between them senders 61-66 & 71A&B -76A&B.
> 10 Wooferton 6 x dual channel RCA 50kw (the second channel empty,
> reputedly sunk by U boat in Atlantic).
Senders 81-86
Russell W. Barnes
news:9e4f47b3...@pc3-stoc4-5-cust243.midd.cable.ntl.com
8><----------------------------------------------------------
> Around then, when the bbc wartime Tx overseas extensions started to be called
> by their real names I tried to work out where all the OSEs were.
>
> I concluded:
>
> 1 Daventry Extension
>
> 2 Start Point a SWB 18 and the Domestic TX converted to
> 75M band at night.
>
> 3 Rempisham 6 hf txs, not sure what? 50kw?
>
> 4 Droitwich extension, (used from after the war for 200KHZ until replaced by
> the ex Ottringham TXs. carried (amongst others( 400kw to a four element
> curtain (suspended between the 700' masts) on 247m in German, It fell down
> one night with the TX on and all the natives thought paratroopers had landed!
>
> 5 Ottringham 4x 200kw MF and LF near Hull
>
> 6 Burghead (or westerglen) carrying Norwegian.
>
> 7 Lisnagarvey (like Start Point a marconi SWB 18 diverted from an export
> order).
>
> 8 Skelton A 6x SWB18 100kw
>
> 9 Skelton B 6x dual channel ST&C CS8 120KW
>
> 10 Wooferton 6 x dual channel RCA 50kw (the second channel empty, reputedly
> sunk by U boat in Atlantic).
>
> Can anyone confirm or expand on this?
You are correct regarding Rampisham (OSE3) and Skelton A (OSE8) and
Skelton B (OSE9). I don't know about the others without looking it up.
Rampisham started out, I believe, with four 100kW HF transmitters, type
unknown..... The Skelton B CS8's were still in use until the last
transmission was closed on 24th March 1990 by Mrs Olive Shallcross, who
was a former T.A at Skelton. Skelton B was demolished in 1991, but with
much modified electronics and new drives! - although the "serpentine"
cooling and blower arrangement, the valves, tuning and final stages were
pretty much the same.
I spent one happy evening shift tuning S76 into a barbed-wire fence -
the open-wire feeder had fallen down between the building and the
switching tower, and I managed to get 10 Amps of 7 MHz into the fence
before the sender protested and a fireball made its way along the open
wire feeder inside the building and set fire to the window frame;
happy days....
Sender 61 was the last SWB18 in use, and was replaced in 1988/9 by a
Marconi BD272 250kW Tx.
Weren't all the Overseas Extensions (OSE's) extensions of Daventry?
--
Regds,
Russell W. B.
http://www.huttonrow.co.uk
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
Russell W. Barnes
> I can remember in the late 60s old gear from OSE8 being sent to ASP as
> spares. It would have been as old as the original kit.
>
> Around then, when the bbc wartime Tx overseas extensions started to be called
> by their real names I tried to work out where all the OSEs were.
>
> I concluded:
>
> 1 Daventry Extension
>
> 2 Start Point a SWB 18 and the Domestic TX converted to
> 75M band at night.
>
> 3 Rempisham 6 hf txs, not sure what? 50kw?
>
> 4 Droitwich extension, (used from after the war for 200KHZ until replaced by
> the ex Ottringham TXs. carried (amongst others( 400kw to a four element
> curtain (suspended between the 700' masts) on 247m in German, It fell down
> one night with the TX on and all the natives thought paratroopers had landed!
>
> 5 Ottringham 4x 200kw MF and LF near Hull
>
> 6 Burghead (or westerglen) carrying Norwegian.
>
> 7 Lisnagarvey (like Start Point a marconi SWB 18 diverted from an export
> order).
>
> 8 Skelton A 6x SWB18 100kw
>
> 9 Skelton B 6x dual channel ST&C CS8 120KW
>
> 10 Wooferton 6 x dual channel RCA 50kw (the second channel empty, reputedly
> sunk by U boat in Atlantic).
>
> Can anyone confirm or expand on this?
You are correct regarding Rampisham (OSE3) and Skelton A (OSE8) and
Skelton B (OSE9). I don't know about the others without looking it up.
Rampisham started out, I believe, with four 100kW HF transmitters, type
unknown..... The Skelton B CS8's were still in use (but with
much modified electronics and new drives! - although the "serpentine"
water cooling and blower arrangements, the valves, tuning and final
stages were pretty much the same) until the last transmission was closed
at a "farewell party" on 24th March 1990 by Mrs Olive Shallcross, who
was a former T.A at Skelton.
Skelton B was demolished in 1991.
I spent one happy evening shift tuning S76 into a barbed-wire fence -
the open-wire feeder had fallen down between the building and the
switching tower, and I managed to get 10 Amps of 7 MHz into the fence
before the sender protested and a fireball made its way along the open
wire feeder inside the building and set fire to the window frame;
happy days....
Sender 61 was the last SWB18 in use, and was replaced in 1988/9 by a
Marconi BD272 250kW Tx. Although the rest of the station was
controlled by the ACS, S61 (the old SWB18) still required the blower
motor running up 15 mins prior to start of transmission, and the HT
still had to be applied manually when watching the clock.
For some now obscure reason, we were forbidden to band-change it! The
railway tracks were still in place, along with the tuning trucks at the
time
of removal.
Laurence Taylor
mark....@gmx.net "Mark Carver" writes:
-> > > It's hogging bandwidth on DAB, and to a lesser extent on DTT, that could
-> > > be used for the domestic services that we do pay for.
-> >
-> > Wot - yet another identical pop station?
->
-> Hopefully not. I was thinking more in terms of BBC7 in stereo etc.
BBC7 is in stereo.
Laurence Taylor
brian...@lycos.co.uk "Brian D" writes:
-> The original wartime 600kw Crowborough transmitter was in use for long after
-> the war, supposedly at 100kw as per international agreement, but when I lived
-> in Sussex, it was too strong to have been 100kw.
I believe it was the original set that was used for jamming purposes in 1970.
Mark Carver
"Laurence Taylor" <laur...@iapetus.demon.co.uk> wrote in message news:104239...@iapetus.demon.co.uk...
>
> BBC7 is in stereo.
On D-Sat and DTT it is. Not on DAB however
Alan Boswell
On LW nearly all transmissions are bandwidth limited because the antenna
size and cost is almost exclusively determined by the bandwidth it's
designed for. A 1% increase in antenna bandwidth means a 3% increase in
the height of the mast(s), and this is equivalent to a 5-6% increase in
capital costs, so there is a strong economic factor driving the
bandwidth down.
The problem is worst at the low frequency end of the LW band, and if the
Allouis transmission on 162 has better quality, it just means they spent
a whole lot more on the antenna.
LW antenna size is governed by a physical principle called the Chu
limit, explained in the Journal of Applied Physics 1948, and all
antennas obey this law.
Alan
>
> I think they are clipping the high frequencies. It sounds distorted. I've
> tried listening on various radios. The high frequencies don't sound too bad
> on the radios with wider bandwidth, but on the narrower bandwidth ones it
> definitely sounds wrong. Instead of speech sibilants practically
> disappearing, as they do on with any other LW station, there's a distorted
> low frequency mush accompanying each "s" and "sh". It's been like this on
> and off for months. I guess this is less likely to be a problem with a
> program feed, and more likely to be someone's idea of making Long Wave sound
> less muffled - by overdriving the treble so much that it clips. There should
> be a better way of doing this, like turning up the treble more before the
> compressor. But I wonder if there's another problem. Can they actually get
> 100% modulation out of this transmitter at 4 kHz? Perhaps the aerial
> bandwidth isn't wide enough, or a transmitter mod is needed. All I know is
> that France Inter on 162 sounds much louder and clearer than the BBC, and
> they seem to be able to achieve more treble without distortion.
Mr Skippy
MHz | 1L 360D | 3/4L 270D| 5/8L 225D | 1/2L 180D |
0.162 | 1850.571 | 1387.928 | 1156.607 | 925.285 |
| 3/8L 125D | 1/4L 90D | 1/8L 45D | 1/16L 22.5D |
| 642.559 | 462.643 | 231.321 | 115.661 |
--
Regards,
Mr. Skippy
skippy(RUBBISH)1...@hushmail.com
Take out the (RUBBISH)
"Alan Boswell" <alan.b...@nospambaesystems.com> wrote in message
news:3EFC0E59...@nospambaesystems.com...
charles.hope
> On LW nearly all transmissions are bandwidth limited because the antenna
> size and cost is almost exclusively determined by the bandwidth it's
> designed for. A 1% increase in antenna bandwidth means a 3% increase in
> the height of the mast(s), and this is equivalent to a 5-6% increase in
> capital costs, so there is a strong economic factor driving the
> bandwidth down.
Until the late 1960s, Droitwich transmitted up to 8kHz - only limited by
the Post Office line. It was then filtered to 4.5kHz to conform to the
European channel width of 9kHz.
BD
It was about April/May1969 when the bandwidth was limited. I was due
to start on night shift there at the time, and on the journey there
after a few days away I wondered why it sounded so crap. I couldn't
beleive they had left this experimental filter in, which spoilt the
audio quality so much. That must have been the start of the decline of
standards.
--
BD
Stephen
news:gemini.3efd94620037a304%brian...@lycos.co.uk...
I have a suspicion that this is the main reason why France Inter on 162 kHz
sounds so much clearer than the BBC, and it's not just because theirs may be
a better antenna. The French probably have better things to do than degrade
their sound quality in order to be sticklers for standards. Poor sound
quality on LW and MW is a self-fulfilling prophecy. The main problem is
bandwidth restriction at the TX which, as you point out, was deemed
unnecessary in the days when the primary medium for radio broadcasting was
LW and MW, not FM. I think the arguments for sticking to restricted
bandwidth don't stand up well to scrutiny. There are very few cases where a
significant audience is trying to listen to an AM station which has another
AM station at comparable signal level only 9kHz away, even at night. AM has
become unpopular because of poor sound quality, but this is mainly because
we make it poor, and keep it that way by day and night, and on low power
stations, when during daylight and on low power stations it is completely
unnecessary to restrict the bandwidth. If we increased the audio bandwidth
to 12 kHz, the same as many DAB stations, there are no instances where
British stations would cause interference to each other, and the majority of
receivers would reproduce this transmitted bandwidth since they were
designed for America's + and - 10 kHz specification.
charles.hope
Stephen <ste...@junkmailblocker.sptv.demon.co.uk> wrote:
> >
> I have a suspicion that this is the main reason why France Inter on 162
> kHz sounds so much clearer than the BBC, and it's not just because
> theirs may be a better antenna. The French probably have better things
> to do than degrade their sound quality in order to be sticklers for
> standards. Poor sound quality on LW and MW is a self-fulfilling
> prophecy. The main problem is bandwidth restriction at the TX which, as
> you point out, was deemed unnecessary in the days when the primary
> medium for radio broadcasting was LW and MW, not FM. I think the
> arguments for sticking to restricted bandwidth don't stand up well to
> scrutiny. There are very few cases where a significant audience is
> trying to listen to an AM station which has another AM station at
> comparable signal level only 9kHz away, even at night.
I believe that you are wrong here. Medium and long wave transmission
carry a long way even during daylight. It is possible to listen to
Droitwich in North Africa, I am reliably told - I know it is audible in
Geneva (first hand experience). Orfordness provides a daytime service in
Vienna.
> If we increased the audio bandwidth to 12 kHz, the same as many DAB
> stations, there are no instances where British stations would cause
> interference to each other,
It's not UK/UK interference that might be the problem, it's UK to "abroad"
where the problem occurs. Because Europe "put its house in order" over 30
years ago, you don't hear the potential problems. They existed in the 60s
and before, I assure you.
BillJ
Scotland.
A special method of modulation is used, one aim being to minimise the
electricity bill!
An unfortunate side effect is that occasionally, music (hymns, organ
music) - also applause behind commentaries (sports, Yesterday in
Parliament) get the audio "chopped" by about 6 to 9 dB (strongly
audible difference) at about 2 Hz.
It RUINS the enjoyment of music; and mars the clarity of commentaries.
Two questions: (a) do listeners to Burghhead or Droitwich hear the
same horrible effect?; (b) can anyone enlighten me with a circuit or
block diagram of the method of modulation?
Thanks -
BillJ
(Edinburgh)
Stephen
news:bdq69t$gkg$1$830f...@news.demon.co.uk...
> I have a suspicion that this is the main reason why France Inter on 162 kHz
> sounds so much clearer than the BBC, and it's not just because theirs may be
> a better antenna. The French probably have better things to do than degrade
> their sound quality in order to be sticklers for standards.
There's a longstanding culture of attention to output "sound" in the French
radio industry. It runs right across commerical stations like NRJ and Cherie,
through RFI and the domestic Radio France services. As a rule Radio France put
their Optimod processors at the transmitter site and tune them up so
everything's nice and bright (or as bright as you can get in AM bandwidth). My
understanding is that the BBC processes Radio 4 at the studio end at the moment
so it can't be tuned to the antenna. Compare the sound with 5 Live which is
processed at the transmitters, albeit more aggressively.
M. J. Powell
<nos...@nospam.demon.co.uk> writes
Do I understand you to mean that there is feedback from the antenna to
the Optimod?
Mike
--
M.J.Powell
BD
> Do I understand you to mean that there is feedback from the antenna
> to the Optimod?
>
Just in as far as the optimod and the particular transmitter are set
up as a unit, so that the signal radiated from that particular
transmitter is 'optimised'[1].
[1] Not necessarily so in my opinion. Usually it is 'optimised' until
it sounds incredibly distorted, but not increasing the bandwidth of
the transmission.
--
BD
BD
> I have a suspicion that this is the main reason why France Inter on
> 162 kHz sounds so much clearer than the BBC, and it's not just
> because theirs may be a better antenna. The French probably have
> better things to do than degrade their sound quality in order to be
> sticklers for standards. Poor sound quality on LW and MW is a
> self-fulfilling prophecy. The main problem is bandwidth restriction
> at the TX which, as you point out, was deemed unnecessary in the
> days when the primary medium for radio broadcasting was LW and MW,
> not FM. I think the arguments for sticking to restricted bandwidth
> don't stand up well to scrutiny. There are very few cases where a
> significant audience is trying to listen to an AM station which has
> another AM station at comparable signal level only 9kHz away, even
> at night. AM has become unpopular because of poor sound quality, but
> this is mainly because we make it poor, and keep it that way by day
> and night, and on low power stations, when during daylight and on
> low power stations it is completely unnecessary to restrict the
> bandwidth. If we increased the audio bandwidth to 12 kHz, the same
> as many DAB stations, there are no instances where British stations
> would cause interference to each other, and the majority of
> receivers would reproduce this transmitted bandwidth since they were
> designed for America's + and - 10 kHz specification.
>
Prior to the early 70s and the introduction of digital feeds for
stereo, the audio quality, particularly for radio3 could be just as
good on MF as VHF. Certainly from one (aged)MF transmitter when fed
from the local studio the MF output was far superior to what came from
the network on VHF. Since then the quality (first on MF and now,
unfortunately on VHF and Digital) has been annihilated in the
interests of loudness. Certainly radio4 is now definitely permanently
distorted on VHF. Radio7 doesn't sound too bad in comparison on
freeview, despite it's low bit rate and mono.
--
BD
Stephen
Depends who set it up. The distortion is optional. An Optimod doesn't increase
the bandwidth but, because it employs multiband dynamic control, it will
increase the density of the audio at certain frequencies which can give the
effect of a more consistently brighter sound. Ultimately, it conditions the
audio for optimum modulation, hence "Optimod". Lots of detailed papers on this
at www.orban.com
Stephen
> "Stephen" <ste...@junkmailblocker.sptv.demon.co.uk> wrote:
>
> Prior to the early 70s and the introduction of digital feeds for
> stereo, the audio quality, particularly for radio3 could be just as
> good on MF as VHF. Certainly from one (aged)MF transmitter when fed
> from the local studio the MF output was far superior to what came from
> the network on VHF. Since then the quality (first on MF and now,
> unfortunately on VHF and Digital) has been annihilated in the
> interests of loudness. Certainly radio4 is now definitely permanently
> distorted on VHF. Radio7 doesn't sound too bad in comparison on
> freeview, despite it's low bit rate and mono.
>
> --
> BD
One thing that mystifies me is why Radio 4 on 720 kHz from Crystal Palace
sounds so dull. This doesn't sound like distortion in the interests of
loudness, but something else. It's dull and boomy, rather like the muffling
you get from Dolby mistracking. It certainly sounds a lot different from the
nearby Radio 5 on 693 kHz from Droitwich, which gives a much brighter and
clearer impression even though the signal strength in London is a little
lower.
M. J. Powell
<brian...@lycos.co.uk> writes
Sorry to be a bit thick. Is there feedback from the Tx to the Optimod?
Say, detected audio from the feeder?
Mike
--
M.J.Powell
tony sayer
<mi...@pickmere.demon.co.uk> writes
In the Optimod's I've worked with 2200, 8200 and 8400 there is no
feedback input from the TX output at all. The only inputs are for
programme audio on XLR's balanced line input or AES/EBU and the outs are
analogue on XLR's and composite on BNC's and AES/EBU on digital. The
8400 has a clock input but that's not feedback.
they have different models for AM though but there doesn't seem to be
any info on these models on their website......
--
Tony Sayer
DB
>
> Say, detected audio from the feeder?
>
No there isn't. But for an Optimod to work as best it can, it needs to be
matched to the transmitter to compensate for inefficiencies in the system.
This is why it's always best to position Optimods at the TX site and not at
the source. In the case of AM Optimods, the setup process involves measuring
the modulation envelope with various test signals, and is well worth the
effort as the improvement is noticeable.
BD
> Sorry to be a bit thick. Is there feedback from the Tx to the
> Optimod?
>
> Say, detected audio from the feeder?
>
Not in the cases I've seen. The output waveform should (preferably
after the aerial) be monitored during setting up, so as to get
compensation set up correctly. ie no tilt/ringing on a square wave (ie
highly clipped (AKA distorted) audio modulation).
--
BD
M. J. Powell
<to...@bancom.co.uk> writes
So we are not talking about a form of pre-emphasis to compensate for the
aerial characteristics?
Mike
--
M.J.Powell
tony sayer
<db_...@hotmail.com> writes
Yes it needs to have very good control over the modulator in the FM
exciter. Rob Orban has written some extensive articles on this,
especially the low frequency response, down to .15 Hz IIRC (yes the
decimal point is in the right place!).......
--
Tony Sayer
M. J. Powell
<db_...@hotmail.com> writes
Right! So there is a connection, via a human, between the aerial and the
Optimod.
Mike
--
M.J.Powell
M. J. Powell
<brian...@lycos.co.uk> writes
Right. Thank you.
Mike
--
M.J.Powell
DB
> Optimod.
>
setup stage. Once it's installed, the "connection" is removed.
Alan Boswell
I would be surprised if the antenna had a 16kHz bandwidth. What happens
practically (I think) is that as the antenna swr degrades at the band
edges, and if there is enough high-frequency audio power in the signal
spectrum, the reverse-power detector in the feed line will cause the
transmitter power to reduce or trip out. That's the case nowadays with
solid-state amplifiers which are a bit sensitive to excessive currents
or voltages, but maybe in the old days the vacuum-tubes were treated
more roughly.
Alan
BD
> Charles I would be surprised if the antenna had a 16kHz bandwidth.
> What happens practically (I think) is that as the antenna swr
> degrades at the band edges, and if there is enough high-frequency
> audio power in the signal spectrum, the reverse-power detector in
> the feed line will cause the transmitter power to reduce or trip
> out. That's the case nowadays with solid-state amplifiers which are
> a bit sensitive to excessive currents or voltages, but maybe in the
> old days the vacuum-tubes were treated more roughly. Alan
>
The aerial/matching system was designed to have an adequate bandwidth
symmetrical about carrier. Voltage feedback on the modulator would
further improve the system bandwidth by correcting for changing
impedances at the valve anodes at higher sideband frequencies. The
system had two transmitters physically paralelled, and additional
equalisation/matching sections were added when running one transmitter
only.
I can't remember the details of aerial/ feeder protection, but
normally for MF/LF, the aerial was DC isolated from earth and fed with
240 volts DC and if any leakage was shown(from a fault or flashover)
it would trip the transmitters. I vaguely remember some impedance?
measuring system on the feeders to the transmitters which tripped
drive power if the transmitter phasing caused any problems.
Compression in those days was via a full bandwidth limiter and IIRC
was not more than 6-8dB, so the problem of excessive reflected HF
sideband power would not occur.
The severe degredation when the 4.5 kHz filter was added was very
easily spotted on my (valve)car radio at the time.
--
BD
Alan Boswell
into a poor load, and the antenna match gets progressively worse at the
band edges. So by pre-emphasising the treble you ultimately cause the
reverse power on the feeder to increase, maybe to the point where it
might damage the amplifier or activate its protection hardware.
Alan
M. J. Powell
<alan.b...@nospambaesystems.com> writes
>I think that would not work, because the final PA cannot work safely
>into a poor load, and the antenna match gets progressively worse at the
>band edges. So by pre-emphasising the treble you ultimately cause the
>reverse power on the feeder to increase, maybe to the point where it
>might damage the amplifier or activate its protection hardware.
Right. Thank you.
Mike
>Alan
>
>
>"M. J. Powell" wrote:
>>
>>
>> So we are not talking about a form of pre-emphasis to compensate for the
>> aerial characteristics?
>>
>> Mike
--
M.J.Powell
John
> I think that would not work, because the final PA cannot work safely
> into a poor load, and the antenna match gets progressively worse at the
> band edges. So by pre-emphasising the treble you ultimately cause the
> reverse power on the feeder to increase, maybe to the point where it
> might damage the amplifier or activate its protection hardware.
> Alan
From memory the whole aerial at Droitwich (Proper name Wychbold) was
re-engineered around 15 or more years ago from a four wires in line Tee Aerial
to four wires in square which lowered in impendance/reactance.
I have the details of the old Tee aerial and the old Aerial Termination Hut
but like most things when I need them there tashed away in box someplace.
But from very vaig memory which maybe well off, I seem to remember the
Q point was 207 KHz with a low impedance of 20.4 ohms, (cannot remember
the reactance) for the antenna at the base. The usual impendance matching
was done which brought the aerial onto 200 KHz then power factor correction.
The Optimod come's with a function which corrects for non-linearities within the
transmitter and aerial system and can compensate for loss at high and low levels.
I idea is a development of equilization used often in the audio industry and by
the BBC.
It's not pre-emphasis but more balancing the audio range..
Similar things were done by the BBC on the old GPO line feeds to transmitters
to compensate for losses via long runs of GPO exchanges.
For a better discription go to
http://www.orban.com/
Go to the downloads page and download PDF manual for the 9000 MF/LF processor
ftp://ftp.orban.com/9000A1/
If you have slow internet link then don't bother.
John