whats the fuss about FM?

[Ian Jackson]

In message [e-mail]>, Tim Lamb [e-mail]> writes

Radio Luxembourg was, as you say '208' - ie 208 metres AM, on the medium wave. It was never on the FM.

If the OP's set is OK on AM, but dead on FM, it's obviously a fault in that part of the circuit that does the FM. While it could be a variety of things, a totally set could be because the local oscillator isn't running. [For a long time I've had a circa 1960 Murphy like this in the loft, and when I find one of my round tuits, I might have a look at it.] It might be worth tuning all across the FM band, and see if there are any signs of life at one end or the other.

[Jim GM4DHJ ...]

we won't let that happen ...

[charles]

My Revox was (and still is) a Tape Recorder

[Sysadmin]

No 1 microvolt for the discriminator to give a stereo output.

[JNugent]

I think I used a dual-standard monochrome set (bought s/h for £12) until mid-1978.

The buttons would certainly have included MW and LW, perhaps even VHF as well (depending on exact age).

I remember the radiogram we had when I was young. It was never used after about 1958, but was still around the house for a year or two until disappearing in a house move. The most memorable feature was the tuning knob - about 2" in diameter and with a sculpted recess near the circumferential egde for one-fingered operation. I can still "feel" the beautifully-tactile shape of that control.

[Mark Carver]

Minimum sensitivity of most FM tuners was between 1 and 2 microvolts to lift a mono signal just out of the noise (the noise generated by the tuner itself, never-mind any externally received noise) Cool the tuner head to  Zero Kelvin and you might do better, but at room temperature you're stuck with Mr Boltzmann.

You needed  1 millivolt for clean stereo reception.

[Chris Holmes]

<Snip lots of good stuff about FM>

Thanks everybody, most interesting. I wasn?t expecting Stereo from the HMV, in fact I?m not sure I?ll get anything, but I?ll give it a try.

Also, unless you are into Classical or R4, IMHO there?s not been much worth listening to on FM since they took ?Pop goes the Beatles? off! (OK, I did enjoy Kenny Everett & chums on Capitol back in the day).

Most of his chums are now on Boom Radio (available in all good outlets and a few rotten ones, but not FM). As they say, their combined age is about

300, but their combined height (Diddy David, Little Nicky, etc) is considerably less!

[Chris Holmes]

Oh, and well done for the Reliant Robin (as opposed to Robin Reliant) ref.

[Max Demian]

I think the first practical FM radio was made by Philips around 1975. It had some kind of circuitry to remove the interference spikes. Stereo and it also played and even recorded cassettes, from radio or microphone.

[Max Demian]

Around 1960 my parents rented a Baird FM radio from Radio Rentals. It wasn't very sensitive, and required a rooftop aerial to work at all. As it warmed up, you had to adjust the tuning. No AFC.

Later they bought a Hacker FM only radio like this, which was much better:

[charles]

I fitted a Philips car radio with FM in 1971. I had a friend who worked for them. As far as I remember (it was 50 years ago) it was simply mono.

[williamwright]

Don't forget Radio Normandie!

Bill

[Pamela]

I had a rooftop FM aerial too. Maybe I was in a poor signal area or just had a lot of multipath. It was bought used but from a reputable Quad dealer.

Years later, a sold-state Technic tuner gave much better reception on the same aerial but perhaps technology had move on a lot by then.

[tony sayer]

In article [e-mail]>, Dave Plowman (News) [e-mail]> scribeth thus

Still got one here, works rather well:)...

[tony sayer]

Still got, one nice machine that:)...

[The Natural Philosopher]

It really wasn't - not the third program. That was the whole point of FM

- it had enough dynamic range to not require compression

>

[The Natural Philosopher]

Unlikely. 1uV was less than the mono decode sensitive of most receivers In fact that is pretty much what the front end noise of most recievers was...

[The Natural Philosopher]

+1, but 100uV was a reasonable limit for *some* stereo.

[The Natural Philosopher]

No. That is only half the picture.

The problem was ultimately that your signal to noise could not be improved by using more bandwidth, and even to get full audio would have required a 40 kHz channel spacing. That would only have allowed about 5 channels on long wave and about 25 on MW

It is interesting to note that narrow band FM using channel widths of

10khz is just as susceptible to noise as AM

The real gain of FM, was that by moving to 100Mhz there was simply more spectrum width: wideband FM is simply a fairly simple way to utilise it.

[The Natural Philosopher]

I have a superb Sony receiver from the 1980s. worth less than £30 now.