Explanation please - Long wave on telephone

[tis your junk]

Fellow solder melter's,

On the basis of "if you don't want this, it's in the skip" I have inherited a Murphy A684 - oh lucky me. Thanks to the BVWS CD I was able to find the circuit diagram (cheers BVWS guys great job ), everything as expected, sales pitch on use of PCB construction etc etc. It was only then that I noticed phono plug on the back labelled "Swiss", the data sheet explained that:-

"This socket is provided so that the receiver can be used in certain areas of Switzerland to receive special L.W. over the telephone lines"

OK thought I, LW audio over telephone lines from a central receiver then use the output stage of the Murphy - only problem is the socket connect to the aerial input of the RF stage.

To me this does not add up, 200kcs down a phone line? Can anyone shed any light on this.

Furthermore did the UK sell so many of these sets to Switzerland that this addition was an economic proposition?

Cheers

TYJ

[paulsherwin]

I've got one of these too, and I asked very similar questions on the forum when I bought it a few years ago Apparently the Swiss did have a system based on putting LW down the phone line which was plugged into the back of a suitable radio using a special transformer or balun. I've not managed to find out much about it and it no longer operates.

I too was surprised Murphy exported enough of these to Switzerland to make the connector worthwhile, though it adds little to the cost of the radio. I haven't come across a similar connector on other Murphy sets (or anybody else's for that matter )

Paul

[ppppenguin]

200kHz down a phone line doesn't sound like anything special in these days of ADSL.

[Steve_P]

It was cable radio - same technology as Cable TV! - but a lot older. They simply pushed 200kHz down a phone line. Nothing special in that now, but then...

The interference from Phone Lines must have been quite something.

Cheers,

Steve P

[dave walsh]

I might be on the wrong track [line] here but is there any connection between this and the Swiss Civil Defence System which remains very pro-active to thisd day? I'm sure that I've come across some sort of ref to a Swiss National Broadcasting Emergency System in the past.

As an aside... I thought at first this thread might be similar to the chap I met in Bexhill who gets Radio 4 on his telephone circuit [from the relay TX down the road] whether he wants it or not. There is a reel of twin feed in circuit in the hall to make it non resonant! Dave

[tis your junk]

Hi Guys,

Thanks for the replies, which I think could be summed up as no one really knows

Paul, I must admit I did not do a search before I put my post up, however even when I search now I can not find the post you refer to.

Dave, yes I've met people who have had similar breakthrough of radio systems, I think the worst was a guy who lived next to the Rugby transmitters who had trouble measuring voltages on anything metallic because of pickup

Anyone know anything more?

TYJ

[wave solder]

Have a look at this:-


http://de.wikipedia.org/wiki/Telefonrundspruch
http://it.wikipedia.org/wiki/Filodiffusione

you may need BABEL FISH for the translation.

to quote another website:-

" it looks very much like what was abandoned in Switzerland in 1997 and still exists in Italy as Filodiffusione - radio broadcast down a phone line. It was introduced in Switzerland 1931 and ensured clear sound in mountainous areas for long wave broadcasting.

In German it was called 'Telefonrundspruch' and it was very popular in hotels and restaurants until the end of its life. The most popular make of TR received was the Biennophone."

[wave solder]

A bit more info here:-

http://www.elettro-scienza.it/NFHFTR.htm

(in Italian but some useful diagrams)

[Telleadict]

Hello

I knew this reminded me of something and now I've found the reference.

The attached is from The 'Practical Wireless' Encylopeadia By F. J. Camm, the 1946 edition. Just shows this idea was presumably quite well known though, as Steve P said, how well it would have worked is anyones guess!!

Bye
William

[60 oldjohn]

Hi I've just found this in Practical and Amateur Wireless August 19th 1939 page 530.
Swiss Wired Wireless.
According to a report from Switzerland, that country intends shortly to introduce high-frequency-wired wire wireless, use being made of the telephone lines. Towards the end of this year, tests are to be made at Berne on five frequencies, vis., 172, 208, 248, 270, and 300 Kc/s.

[Aerodyne]

I found the same entry as William did about the subject in my 1938 edition of Newnes Wireless constructor's Encyclopaedia, so I looked it up in my first edition of the same publication (undated but a guess would be 1933). Sure enough, it was in there too.
-Tony