When did VHF change to FM?
Richardcoulter
Posts: 30,347 Forum Member
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As a child, I used to hear the term VHF a lot, particularly in regards to stereo radio broadcasts.
At some unknown point, this was replaced by FM.
Are they the same thing, with a different name?
If so, why/when did it change?
Thanks.
At some unknown point, this was replaced by FM.
Are they the same thing, with a different name?
If so, why/when did it change?
Thanks.
0
Comments
VHF means Very High Frequency
FM means Frequency Modulation
So VHF refers to a part of the radio frequency spectrum and FM to the means by which information is encoded onto a radio signal.
You could use FM at any frequency and any modulation method in the VHF band. It just so happens that when broadcasting started in the 88-108MHz band most usually associated with the term VHF the FM system was chosen to encode the audio information onto the radio signal. It could just as easily have been AM as used on Medium and Long Wave broadcasts.
The use of FM to mean broadcasts in the 88-108 band seems to have become more common when commercial broadcasting started up 40 years ago as far as I can remember.
Such as the 27 MHz Citizen Band which is just in HF.
Presumably because FM is less susceptible to some forms of interference than AM. So in theory it can give higher quality reception than AM.
ILR used the term VHF well into the 80's.
In the '70's and '80's, Radio/Cassettes, Music Centres and separates tuners manufactured in the far east usually had FM marked on them rather than VHF, so I'm guessing that the broadcasters realised that in order to encourage the use of VHF, they should refer to FM, because that's what it said on many radios.
Spot on, British made sets had dials marked MW/VHF and wavelength (for LW/MW), Japanese sets said AM/FM and frequency. Most british stations still used wavelengths (Radio 1 on 247, Luxembourg 208 etc) long after radio manufactures changed over to dials in frequencies.
http://hub.tv-ark.org.uk/images/bbctwo/images_cont/1979/onradio21985.jpg
They didn't use the term VHFM, it's just a play on words for the graphic, that's all. That picture is from the late 80s when, as has been explained above, VHF and FM were both seen on the different radios and stereos of the time.
ILR was using VHF until 1988 from what I can remember.
Yes the family radiogram (made in England) in the 1970's had medium/long waves marked in metres, and the hi-fi band marked VHF.
The BBC was on the money with this one as the whole band 30-300 MHz is called VHF.
And who could ever forget this legendary Radio jingle....
https://audioboom.com/boos/561561-radio-1-275-285-and-stereo-vhf-1980
Pity the Government could not have put a big import tariff on AM/FM marked sets to keep this quirk of British radio alive;-)
This mainly came about when the ILR stations of the time were forced to split frequencies, i.e stop broadcasting on both AM and FM. The Government said if companies continued to do this they would take one of their frequencies away.
So, most ILR's split into xxxxx FM on FM offering chart pop / Top 40 and xxxxx Gold on AM, offering 60's / 70's music. There were a few exceptions but that was what the majority did.
For example, here in Leicester, Leicester Sound, which had been broadcasting on 1260 AM / 238 metres and 103.2 FM, split into Sound FM on 103.2 FM and GEM AM on 1260 AM (this later changed to 24 hour Asian programming in 1992, but that story has been told more than once in other threads!)
Some did it sooner than others, Radio Broadland didn't split at all until 1995, and Radio Wyvern didn't until 1996 if memory serves me correctly, I think they were the last one to do so.
A lot of ILRs used "FM" especially in their sung jingles. I don't recall any of them having jingles referring to "VHF".
I remember when Beacon launched its Shropshire service in July 1987, and they had a jingle saying VHF 103.1. Fairly sure they had an alternate version of it saying FM 103.1, but it wasn't long before they stopped referring to VHF altogether.
And conversely, VHF airband (108-137 MHz) uses AM.
Did they always refer to metres for wavelength or was it yards in the UK in ye olde days? I'd be surprised if our old early radio boffins would tolerate such nonsense
Perhaps Stereo Fm isnt refereed to as it would make low bit rate poor quality mono DAB sound bad.
CD quality my backside. and they want to replace FM with DAB?
American early radios seemed to have used wavelengths in 'meters'!!
http://antiqueradios.com/forums/viewtopic.php?t=73557
I remember in the 1980's, Radio 1s Richard Skinner had a joke jingle quoting 275/285 meters in yards!