106.0

[famefm]

Are you saying that those 2 afull stations are spreading to far and arnt set properly for their main frequency? And Mr Albert you are definitely the expert on here so do you know why there is a 5 point gap between 104.9 and 105.4 for London?

[Albert H]

104.8MHz and 105.2MHz are 400kHz apart - 100kHz more than the official minimum of 300kHz. They still try to put stations of that power level 400kHz apart because there's still a stupid belief at OFCOM that domestic radios can't discriminate between more closely spaced stations.

The 104.9MHz rig is a nasty old piece of crap that was brought from Wrotham to Crystal Palace some years ago for the start of Radio 1 on FM. Moving it up 100kHz would be tricky for a number of reasons - the rig would require major surgery (again - after it was moved up from 94.9MHz), there are issues with where the harmonics of 105MHz fall, and there would be an inconvenient (and difficult to filter) set of mixing products that would appear.

Pirates usually don't understand the issues with just diving on to any "unused" frequency in the band. In most cases - at the flea-power levels the pirates use - they won't cause too much interference, and any they do cause will be over a fairly small area. If that area is Hackney or Stoke Newington, OFCOM don't give a Flying F**k since they don't think that anyone important enough to matter lives there - what the Yanks would call an "NHI" crime!

In reality, there are all sorts of problems with frequency choice as the power rises. When you get to 500 Watts or more, with well-engineered aerials and a high site, you can start to cause significant problems over quite a wide area. OFCOM are out like a shot because they immediately get complaints from the broadcasters paying for licences and from the professional complainers in the Councils and government!

it's a mess, and it's not going to get any better.

[famefm]

Thank you for that because back in 1987 when radio 1 first appeared on 104.8 it was a lower sound quality than the more professional pirate operation's at the time?

[teckniqs]

Wasnt it apparently still AM modulation quality when R1 first started up on FM?

[Albert H]

Radio 1 was using the feed that was pre-processed for AM. It sounded horrid! I put on 200 Watts of nice sounding stereo 500kHz below it, and it sounded like Radio 1 was the poor quality pirate!

[famefm]

It wasn't for JBC was it that's the only one I remember at the time?

[Albert H]

Hmmm!

[Albert H]

JBC had a ridiculous multiple cassette deck that would allow them to play eight cassettes one after the other. The cassette deck mechanisms came from a firm that made telephone answering machines and the erase heads on the decks were removed to be replaced with foil sensors.

The cassettes themselves had to be modified by painting on a stripe of silver-loaded conductive paint near to the end of a side, and when this shorted the foil sensor, that deck would stop, and the next would start. As long as they didn't use C120s, the thing functioned flawlessly!

When the foil was detected on the final cassette, the whole lot shut down, including the transmitter.

I recently found my old notes for the logic circuit to control the cassette decks!

[Effemm]

*This is what kids in school should be taught in History lessons,wonderful stuff...Mr H your posts are a pleasure to read. *

[famefm]

Bring back JBC 104.3 cira 1989?

[Albert H]

Sorry - not JBC, it was DBC. Suffering from brain fade!

It was MUCH earlier than that.... The multi-cassette player was built in 1981!

[famefm]

I wasn't going to argue but I thought that sounded a bit primative for jbc because they were mostly live at the time especially the excellent challenger?

[Albert H]

DBC was an interesting - and very experimental - station. It had the first female reggae DJ that I ever heard (on the radio) - the lovely Miss P!

[famefm]

And the people who started JBC where DBC djs first and did not want to stop when the original DBC management called it a day first time around although DBC did come back again separately?

[Albert H]

I vaguely remember a re-started DBC some years later, but it wasn't many of the original people and it didn't last for long!

I was looking at some old notebooks earlier, and found my notes about an install on a block at Notting Hill Gate for DBC - for the Carnival, of course. I remember blowing the input to the link receiver with a static zap from the aerial downlead. I was thrown across the room by the static. Luckily I had a spare link receiver in the boot of the car downstairs....

One of the other problems was that there was no accessible mains on the roof, and I had to run a lead down the dry riser, out into the corridor downstairs and into the back of one of the permanently powered Fire Safety luminaires. Concealing the cable wasn't too difficult, but I had to dress the part of a Council workman!

They linked on Band IV from a very posh flat in Kensington Church Street that was owned by some record producer who was a friend of theirs. Luckily the neighbours were used to loud music coming from there (and probably the "herbal" aromas!), so they didn't get an unfriendly visit! That was the last time I spent the whole length of the Carnival in the area.

[famefm]

Some one mentioned UK obsession on here and I came across a recording I did in Windsor Great Park a few years ago and it was very clear so 106 does work on a good radio set?

[Albert H]

If your receiver has good selectivity, accurate filtering and good sensitivity. you should be able to separate stations 200kHz apart as long as they're not over-deviating. However - the combination of over-deviation and less than ideal receivers means that the practical minimum spacing should be 300kHz.

At 300kHz apart, there are 68 discrete frequencies up Band II. How many legal stations do we have in London? More to the point: How many BBC regional transmitters can be heard here?

[famefm]

My normal stereo receiver can only separate. 3 mgz with the strong legal rubbish stations? you know the one's 1054 to 1062 and my good one .2 but can you get a set that could separate only 1 point if an unwanted strong station like 1062 was next to it?

[Albert H]

No. Because the modulation of the two stations would be overlapping. "Capture Effect" should mean that the stronger signal wins (look it up), but with two weaker signals, you'll get a mushy mess.

I can build receivers that can discriminate to 1 kHz or better at UHF, but these are specialist things, not suited for wideband, high audio quality modulation.

[famefm]

Thank you Albert but I can receive stations that are 1 point apart that are on lower power okay and here's another question in my area Windsor Great Park when tuning into house 100.3 .I have the ariel pointing the right way and when I move the coax away from the pole it gets house when the coax is against the pole it's the massive south coast class fm signal and the ariel is 3 elements if I put more elements it's only classic 100.3 what ever I do?