USA FM Radios

[radiomanic]

Why is it that US f.m. Radios do not opperate so well . if at all. here in the UK.

I have a few such sets that are a waste of space on FM.



Frank

[Kat Manton]

The only immediate difference which springs to mind is the pre-emphasis is different.

UK, Europe and Australia use 50uS whereas North America uses 75uS; so for proper frequency response in the UK a US-made set ought to have an R and/or a C changed somewhere.

Apart from that; I'd expect a US valve VHF set to be around as deaf as a UK valve VHF set

Kat

[mickjjo]

According to the information on this site:-

http://en.wikipedia.org/wiki/FM_broadcasting_in_the_USA

FM sets made after 1945 in the US used the same frequency range as in the UK , so they should work OK..... .

Regards, Mick.

[avro]

I have a couple of radios designed for operation in the US/Canada, the only thing I can say about them is that they generally get better reception than the local European variety (the Hacker Mayflower outdoes them all though )

Avro (grew up on the Great Lakes)

[radiomanic]

Thanks folks. Interesting stuff. But!. Maybe its just that early FM valve radios were just stone deaf. The sets in question are Zeniths and RCA of 1942/50 period. Great AM section but nothing to speak of on FM. Not even with the correct aerial. Beats me!!!!!!!!!!!!!!!!!!!!?


Frank

[Nickthedentist]

These are certainly early models, Frank, produced well before we had FM here.
What frequency range do the dials say they'll tune to on FM?

Nick.

[Hybrid tellies]

A lot of early American tellies did not use an RF stage, I suppose as most stations were local and on VHF they could get away with it. If they used the same practice on their early valved vhf/fm tuners ie no RF front end, then this would explain their deafness when compared to European/UK sets.

[stephanie]

Also the valves used in some of the more inexpensive FM radios were not quite up to the job they were pressed into doing.

It was one of those "do it with what you have available and make it as cheap as possible."

[radiomanic]

Well Now.

The FM sections on some sets are 88 to 108 with an additional band of 49. Which I guess most probably was used at some time prior to TV sound allocation?
Seems that early US sets transposed to the UK don't settle in well. That's a shame because the designs are just perfect and just the thing for a collector to drool over.

And Stephanie. I shall be in New York State early September. But no longer looking for vintage vhf.

Thanks all Frank.

[stephanie]

The original commercial FM band, at the time of Major Edwin Armstrong (inventor of frequency modulation) was between 42 and 50 megahertz as originally licenced by the Federal Communications Commission (FCC).

Originally this was occupied by VHF Channel 1 for television - although broadcasts on this very low frequency range proved unsatisfactory.

There was a famous war between Armstrong and his former friend David Sarnoff (head of RCA Victor) - who wanted to do away with FM.

Sarnoff's company, you see, owned a large nationwide network of MW stations and was one of the front-runners in the development of television. Sarnoff saw this as a threat to his existing MW properties and RCA's marketing of TV.

Around 1945, Sarnoff somehow persuaded the FCC to re-allocate FM to the current band (88-108 mhz), thereby rendering obsolete thousands of radio receivers and transmitters. For a while, some companies made dual-band radios covering both the original and the new 88-108 mhz band.

You can see more details here:

http://www.libertyhaven.com/noneofth...rmstrong.shtml

There are lots of websites out there dedicated to Major Armstrong. His famous tower at Alpine (in the state of New Jersey) still stands and is actively used as a communications antenna - mobile phones, 2-way radio. pager services are now up there.

There is one lone FM station: WFDU 89.1 from Fairleigh Dickinson University in the town of Teaneck.

Go here:

http://www.qsl.net/w2xmn/Pages/antennafarm.html

This past June, a commemorative broadcast on Armstrong's original FM frequency (42.8 megahertz; station W2XMN) was produced. The experimental station now on that frequency is WA2XMN.

It was audible throughout the entire New York City metropolitan area the way Armstrong intended: In full, glorious wide-band, static-free frequency modulation; albeit in mono.

http://www.wa2xmn.ar88.net/

[paulsherwin]

In the 40s it was by no means certain that FM would become the hifi broadcasting standard. I know the BBC were experimenting with wideband AM on VHF at this time, similar to 405 line TV sound. It's just as well they made the right decision since backwards-compatible stereo would have been a real challenge

Best regards, Paul

[oldeurope]

Thanks for the interesting links Stephanie.

Early FM sets in germany are made with the "Armstrong Lizenz".

These sets have a very good sound.

Kind regards
Darius

[mikelect]

Originally Posted by stephanie

The original commercial FM band, at the time of Major Edwin Armstrong (inventor of frequency modulation) was between 42 and 50 megahertz as originally licenced by the Federal Communications Commission (FCC).

I have an American radio book titled "Everybody's Radio Manual" published in 1945 where there is an article on building an "Inexpensive FM Receiver" and I quote " Due to the ultra-high frequencies used in FM (41-44 mega-cycles) signals cannot be picked up at greater distance."
Which is even lower than Stephanie quoted.

Mike

[tubesrule]

After Armstrong's falling out with RCA in the mid 30's, he went to GE to have his early radio's manufactured. GE was much more receptive as they didn't have the lock on MW AM that RCA did, and saw this as an opportunity to get in on something potentially big.
This GE HM-80 radio is from 1938 and receives the 39.5-45MHz band. It was a set manufactured in limited numbers for commercial sale by GE, although it is listed for "Amateur and Experimental Reception". GE also had a console version of this set out in 1938, and an earlier console set covering the same band in 1937.

Darryl