# BBC Long Wave



## david.hopcroft (Jun 29, 2005)

Many of you will have seen this in the papers yesterday, that BBC Long Wave broadcasts may end in the not too distant. Apparently there are no more valves to power the transmitter !!

http://www.telegraph.co.uk/culture/...e-radio-could-leave-sailors-high-and-dry.html

A bit like the Post Office W5 transmitters. BT bought out the last remaining PA2 valves from Plessey at Paignton.

David
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## Mad Landsman (Dec 1, 2005)

New transmitters are available, if there is a will. 

Radio Denmark have in recent years replaced their old valve transmitters and are still transmitting on 243kHz. 
I think that frequency was used by the Russians previously, but they closed down theirs last year. 

http://www.nautel.com/press-releases/danish-radio-returns-long-wave-transmission-nautel-transmitter/

http://www.nautel.com/resources/customer-stories/danish-radio/




As an aside - in the Telegraph article they show a stock photo of: 'A Boat navigates a storm' - Rather obviously it is a boat crossing the wake of the camera boat on an otherwise calm sea.... but what do I know?


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## sparks69 (Dec 18, 2005)

Do they still make LW domestic Rx's ?


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## Mad Landsman (Dec 1, 2005)

sparks69 said:


> Do they still make LW domestic Rx's ?


Yep! 

http://www.robertsradio.co.uk/product_details/R9962.htm


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## Dartskipper (Jan 16, 2015)

Just another example of the Beeb losing sight of what it is supposed to be, i.e. a public broadcasting service that should reach the whole population with good quality radio programs and service. It still champions the switch over to DAB, 5Live in particular and one Nicky Campbell extolling its brilliant clarity and quality of sound. Well excuse me, my DAB set is back in its box, and I live near the Sandy Heath transmitter. I had DAB in my last company car, and it was total rubbish when on the move.
It seems the BBC don't have any decent engineers any more with the wit, wisdom, and ingenuity to sort out technical issues. The attitude appears to be, "It's too difficult to fix, so chuck it away."

Roy.


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## King Ratt (Aug 23, 2005)

My car radio at this moment at my front door is receiving French stations on 162 Khz, 183 Khz and as strong as BBC on 198 Khz. Also weaker but readable French stations on 216 Khz and 234 Khz. This is in South West Scotland at 55 North and 5 West. I often hear these stations and it is not freak propagation.


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## trotterdotpom (Apr 29, 2005)

King Ratt said:


> My car radio at this moment at my front door is receiving French stations on 162 Khz, 183 Khz and as strong as BBC on 198 Khz. Also weaker but readable French stations on 216 Khz and 234 Khz. This is in South West Scotland at 55 North and 5 West. I often hear these stations and it is not freak propagation.


Nowt to do with propogation, KR - it's the Auld Alliance.

Vive L'Ecosse!

John T


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## King Ratt (Aug 23, 2005)

Well said,John T. Nothing to beat a bit of French tongue,eh?


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## Varley (Oct 1, 2006)

With FETS of one sort or another utilised for switching in MW scale inverters, PWM at that, I imagined that engineering a semiconductor only AM transmitter at 200 KHz or thereabouts would be doddleish.


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## LouisB (Dec 23, 2007)

King Ratt said:


> Well said,John T. Nothing to beat a bit of French tongue,eh?


https://www.youtube.com/watch?v=LwI-y8-tvTg


LouisB.


(Scribe)


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## GBXZ (Nov 4, 2008)

What was the reason for the BBC shifting the radio four frequency from 200Kc/s to 198Kc/s ?


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## Mad Landsman (Dec 1, 2005)

Varley said:


> With FETS of one sort or another utilised for switching in MW scale inverters, PWM at that, I imagined that engineering a semiconductor only AM transmitter at 200 KHz or thereabouts would be doddleish.


There ARE transmitters commercially available - Nautel and Thomson are a couple mentioned so far. 

It just seems that the BBC are using lack of valves for their own kit as an excuse to walk away and do not want to deal with the basic issue.


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## johnvvc (Feb 8, 2008)

david.hopcroft said:


> Many of you will have seen this in the papers yesterday, that BBC Long Wave broadcasts may end in the not too distant. Apparently there are no more valves to power the transmitter !!
> 
> http://www.telegraph.co.uk/culture/...e-radio-could-leave-sailors-high-and-dry.html
> 
> ...


Ah, the old W5. Clearing out the 'shack' the other day I came across one of the old Post Office transmitter manuals, I think that was a W5. 

Wonder where all the old transmitters went...


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## Varley (Oct 1, 2006)

R651400 said:


> Probably if it is home-brew as were (to the best of memory and knowledge) the BBC LW transmitters I saw at Rugby all those years ago.
> Not so in France 2015.
> 
> http://thomson-broadcast.com/portfolio2/s7hp-long-wavemedium-wave-transmitters-2/


I'm impressed although I did mean a doddle for engineers rather than a doddle for the 8 year old , chess set box and cat's whisker. 900 KW HIGHER POWER AVAILABLE ON REQUEST - and appreciation of lower CO2 emissions - fabulous PR for fabulous kit.


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## Troppo (Feb 18, 2010)

If it ain't IP, they don't want to know...


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## david.hopcroft (Jun 29, 2005)

Re #17. I know where one bit of the W5 at GKZ went. It is a real 'discussion piece' for visitors. Getting them to guess what it is usually starts the ball rolling !!

They may well have been Marconi's at Droitwish. I showed a couple of guys round GKZ a few years back and when I showed them our pirze Marconi H1000 reserve trasnmitter, one said ' Oh yes, we use one of those as a drive unit at Droitwich ' !!

David
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## Bob Murdoch (Dec 11, 2004)

What happens to Test Match Special. Please BBC dont close it down. 
My morning would not be started properly if I could not listen to Farming Today. When they announce Tweet of the Day, it is time to get out the scratcher and be thankful for another day.
Cheers Bob


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## Troppo (Feb 18, 2010)

It will be a sad day indeed...but you just know that the bean counters and bureaucrats have lots of excuses all ready.... too expensive...covered with other transmitters, blah blah.


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## trotterdotpom (Apr 29, 2005)

LouisB said:


> https://www.youtube.com/watch?v=LwI-y8-tvTg
> 
> 
> LouisB.
> ...


Louis, I clicked on your link in the anticipation of some Gallic linguistics but I needed an iTunes password. Sadly, I've forgotten mine. Not to worry, I expect I'll get there eventually, I just need to think outside the box.

Re the BBC Longwave, can't they replace the valves with transistors but using thicker string?

John T


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## Coastie (Aug 24, 2005)

Playing devils advocate here, why does the BBC need Long Wave when for a LOT less power they can cover the world on internet which can be picked up by just about anyone with a phone these days?

However!

The recent broadcast of Radio Caroline North (yes, really!) using Manx Radio's 1368kc/s TX via an internet feed from the Ross Revenge anchored in the river Blackwater to Manx Radio had a lot of internet listeners via their internet stream. BUT, those that could, tried to listen to the 1368 transmission.
On my forum I asked the question as to why people would want to listen on crackly, fady MW when they can have studio quality stereo in their living rooms.
I was surprised by the replies.


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## Dartskipper (Jan 16, 2015)

Coastie said:


> The recent broadcast of Radio Caroline North (yes, really!) using Manx Radio's 1368kc/s TX via an internet feed from the Ross Revenge anchored in the river Blackwater to Manx Radio had a lot of internet listeners via their internet stream. BUT, those that could, tried to listen to the 1368 transmission.
> On my forum I asked the question as to why people would want to listen on crackly, fady MW when they can have studio quality stereo in their living rooms.
> I was surprised by the replies.


I expect they all belong to the generation that remember Radio Luxembourg, Radios; Caroline, Atlanta, London, City, Scotland, Britain Radio and the rest. The crackly fading reception was all part of their charm, although they were all MW band broadcasters of course!

Roy.


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## Coastie (Aug 24, 2005)

That's quite correct Roy. There were a couple of people in Germany who listened via Medium Wave despite the fact that tinternet was available.


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## Coastie (Aug 24, 2005)

My old valve (tube) PYE still has!

Speaking of which I love this song: https://www.youtube.com/watch?v=a2GpEoZrS04


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## Dartskipper (Jan 16, 2015)

I remember our old EKCO radio, made just down the road in Southend, Essex. The dial had many exotic place names on it. Hilversum, Athlone........BBC Home, BBC Light,.........

My first transistor radio, a Decca Debutante has the print scratched away on the dial "around 266 metres on the Medium wave." (As Kenny Everett used to announce.)

Roy.


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## david.hopcroft (Jun 29, 2005)

Today is BBC Radio Lincolnshire's launch on DAB.

I was talking to a young man in Louth who was saying he had just bought a DAB radio for his car. He had driven up to the top end of town to tune it in to his favourites. When he got back home nothing on DAB worked. So much for progress then........

David
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## Dartskipper (Jan 16, 2015)

david.hopcroft said:


> Today is BBC Radio Lincolnshire's launch on DAB.
> 
> I was talking to a young man in Louth who was saying he had just bought a DAB radio for his car. He had driven up to the top end of town to tune it in to his favourites. When he got back home nothing on DAB worked. So much for progress then........
> 
> ...


Yep. Sounds about right. I had a DAB unit in my last car. Lost the signal after about 5 minutes driving. Stayed on MW for the next 4 years. No DAB in my current car, and it isn't missed.

Roy.


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## david.hopcroft (Jun 29, 2005)

I should have said in#33 that Louth is only about 10 miles from the 1285 ft Belmont transmitter. Though I think because of DAB a few feet may have been lopped off the top to save on maintenance costs. Sounds about right too !!

David

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## jimg0nxx (Sep 1, 2005)

For several years I have had two DAB radios in my house (near Scarborough) and get faultless reception on umpteen stations.
I regularly drive between home and Guldford in Surrey. Apart from a couple of fairly deep valleys on the Yorkshire Wolds, reception is perfect on my car DAB radio.
Jim


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## Varley (Oct 1, 2006)

I wouldn'ttt call my ear for detail anything lessss than pedestrian but hasss anyone got a DAB with software that doesss not extend any phrase ending in a sibilantttt?


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## Farmer John (Feb 22, 2012)

Why does a powercut turn on my DAB radio when the power returns? Why can I not increase the volume to suit me, but instead have to choose between 5 (inaudible) and 6 (best heard from another room). And what happened to 2LO?


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## Varley (Oct 1, 2006)

Sssorry Farmer John explaining thatttt I cccertainly can'tttt


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## Farmer John (Feb 22, 2012)

Darn, Varley, I was depending on you.


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## Varley (Oct 1, 2006)

Many a vessel has found that rock!


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## Mad Landsman (Dec 1, 2005)

Sounds like a lin instead of log pot in the AF gain - but digital!
Wow, we've really progressed, haven't we?


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## Varley (Oct 1, 2006)

On the modulating techniques of my school days I suppose the answer is that providing the bandwidth is sufficient then the fi can be as hi as you want regardless of modulating technique. However those same school days taught that the sampling rate for digitizing had to be several (can't remember how many) times higher than the highest frequency in the sample end to reduce quantizing error to commercial quality.

How then does DAB allow better use of the spectrum?

Whilst I am too fond of supposition I continue supposing here that it is because we are using the best decoder known to man - the brain - to fill in the gaps. Allowing economies in what is encoded to reduce demand for bandwidth relying on the brain to recreate the untransmitted data from experience (unconsciously of course).

Experts, end my misery please.

I think the most piteous thing about dropping AM would be that the 7 year old could then no longer knock up a receiver in chessmen box and a few bits from the old Tottenham Court Road shops (when it was a treasure trove for the gadgeteer).


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## Naytikos (Oct 20, 2008)

posted by Dartskipper:


> _The dial had many exotic place names on it. Hilversum, Athlone........_


all depends upon one's point of view, I suppose.


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## Dartskipper (Jan 16, 2015)

Naytikos said:


> posted by Dartskipper:
> 
> 
> all depends upon one's point of view, I suppose.


After Ilford, Essex, anywhere was exotic, even Dagenham (Jester)


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## david.hopcroft (Jun 29, 2005)

Better Use of the Spectrum ??

Whilst I am not fully aquainted with the technical aspects of sampling rates etc...... the Mr Cynical in me would suggest that digital = narrow bandwidth = more channels avaiable in a given space = more earning power !! 

Nothing to do with aesthetics, just another way to grab our money without us having a chance to enjoy the fruits of our labours. 

David


ps. I did say the Mr Cynical in me !!!!!

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## Varley (Oct 1, 2006)

David, My point was that with the sampling rate a multiple of the highest frequency in the material to be transmitted only tricks can squeeze that into a smaller bandwidth that the simple DSB AM transmission of double the highest frequency (I can't remember what it is for FM which is more relevant due to the wider band concerned but it is no where near that once the infinite sidebands are clipped).


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## david.hopcroft (Jun 29, 2005)

A Foster-Seely discriminator was my limit at college in 1963.

What I was trying to say was that it seems to come down to cost these days and as the aesthetics of quality come at a price, do not play a part. 

David.


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## Varley (Oct 1, 2006)

R651400 said:


> #50..You must be the only one who knows what you're talking about?
> Can you simplify?


An AM transmission of commercial R/T quality limits the AF to 2500 Hz (? can't find reference. Memory said 1500 ham blog reckons 3000).

DSB bandwidth is carrier plus and minus 2500 or a total of 5000 Hz.

To turn AF which might contain a frequency as high as 2500 into a digital representation it is necessary to measure amplitude 10000 a second (so we are now told, I remembered it as about 7).

Quantizing error is that between the original and reproduced waveform when it is caused by:

The actual amplitude between two measurements is radically different to that when the other two were taken (insufficiently high sampling rate).

The number of bits used to represent the value measurements is too small to allow sufficient precision (can we liken this to decimal places?).


With DAB we need to receive the bit stream at the same rate as we would an AM transmission otherwise we would have to wait for the data to be received and so experience a much larger delay than that of conversion and processing we do already.

I am afraid my brain is beginning to hurt and thinking of the bandwidth required to transmit 10000 8 bit 'words' a second escapes me. It is, however clearly more than the sampling frequency of 10000 which is good enough to show that the bandwidth required is higher than analogue.


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## Varley (Oct 1, 2006)

david.hopcroft said:


> A Foster-Seely discriminator was my limit at college in 1963.
> 
> What I was trying to say was that it seems to come down to cost these days and as the aesthetics of quality come at a price, do not play a part.
> 
> David.


David,

I could be very mean and seem surprised that you 'did' VHF in 63. When did it come into the carriage requirements?

You are right of course. It must be.

David V


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## cajef (Feb 8, 2012)

R651400 said:


> #50..You must be the only one who knows what you're talking about?


I find that with all his posts.(EEK)


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## david.hopcroft (Jun 29, 2005)

David

My ticket - G/437, dated 8th March 1963 - certainly did contain an exam question on that very topic. If memory serves, it also asked about basic construction and description of operation of a transistor amplifier. 

AEI had Cossor valve driven VHF sets. Even the VHF Ch16 & 26 at GKZ when I arrived in 1968 was a large Marconi cabinet that had valves in it. Ron will maybe remember this ?

David
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## Ron Stringer (Mar 15, 2005)

david.hopcroft said:


> AEI had Cossor valve driven VHF sets. Even the VHF Ch16 & 26 at GKZ when I arrived in 1968 was a large Marconi cabinet that had valves in it. Ron will maybe remember this ?


That was probably MWT product, not MIMC. They produced several types of VHF transceivers to serve as base stations to communicate with their vehicle mobile sets used by the police and other emergency services and vehicle fleet users.

At MIMCo we had _*Nautilus *_and then _*Argonaut*_ VHF transceivers, both totally thermionic valve/tube devices. The former came out in the mid 1950s and Argonaut entered service in 1960. That continued to be sold until the start of the 1970s, when it was replaced by the first of the badged products bought from Svenska Radio AB (SRA). Their _*ME-30* _solid-state VHF was marketed as _*Argonaut S* _and signalled the end of the thermionic valve in MIMCo VHFs.


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## Troppo (Feb 18, 2010)

The problem with UK DAB is that the transmission bit rate is too low.

The old story - they have only x Mb of b/w available on the multiplex, so they lower the bit rate to fit more stations in....

See here for more info:

http://www.techradar.com/au/news/car-tech/why-dab-radio-in-the-uk-is-broken-and-how-to-fix-it-1217586


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## david.hopcroft (Jun 29, 2005)

As you say Troppo..........'to fit more stations in'

Never mind your quality feel the width of our wallets.......... ?

David
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## trotterdotpom (Apr 29, 2005)

R651400 said:


> What's Oz doing in the DAB direction?


Dunno, never heard of it. I thought DAB referred to the Rugby League incident involving the Tongan player, Hopoate .... Digital Ar$e Busting (look it up).

John T


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## trotterdotpom (Apr 29, 2005)

A dab is not a DAB ....they know their plaice. World Cup Rugby .... Do people actually watch that Sh1te? Hopoate was a Rugby League player who (naturally) wanted to be a Yorkshireman (doesn't everyone?) but was excommunicated for sticking his fingers up other players' botties. Definitely a tryer.

John T


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## Troppo (Feb 18, 2010)

We use DAB+ here.

(Thumb)


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## trotterdotpom (Apr 29, 2005)

Troppo said:


> We use DAB+ here.
> 
> (Thumb)


Thanks, Troppo. In the few years' I've got left, probably I can manage without it.

John T


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## Troppo (Feb 18, 2010)

yes, it is useless outside the capital cities...


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## Coastie (Aug 24, 2005)

david.hopcroft said:


> Many of you will have seen this in the papers yesterday, that BBC Long Wave broadcasts may end in the not too distant. Apparently there are no more valves to power the transmitter !!
> 
> David
> +


I hope someone has remembered to tell our RN Submarines. Apparently, if they go to switch on the radio and BBC Radio 4 Long Wave cannot be heard, then that is one of the triggers to firing a missile at Russia!! (No LW Radio 4, London must have been wiped out, fire the missile!)(EEK)(EEK)(EEK)(EEK)


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