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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

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Old 27th Sep 2023, 9:46 am   #1
Welsh Anorak
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Default Cossor 520 - no stations

Hi

Not sure if this is a fault or not.

I've done a fairly basic resto on this - waxies and electrolytics replaced plus the rectifier valve. Now all seems well - it's very lively with a healthy click from the wavechange switch. Connecting a wire from the aerial terminal gives a lot more noise with all the buzzes, crackles and whistles you expect when tuning on all bands.
However there's no real stations - just the odd bit of speech now and again. Turning off the nasty RF emitting electronics helps (and of course there are lots in my workshop) but it's still not getting stations - or am I expecting too much from what appears to be a pretty simple design?

I'm more a TV and audio man so I don't have an RF generator or useful things like that.

Incidentally it has a Gram input but no corresponding position on the wavechange switch. Do I assume you simply find a quiet part of the band and use it that way?

Thanks!
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Old 27th Sep 2023, 9:58 am   #2
G6Tanuki
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Default Re: Cossor 520 - no stations

The number of stations broadcasting on MW/LW has dropped massively in the last couple of years.
Absolute has gone, Smooth has gone, the only real remnants are a few low power Asian stations, Talksport, BBC 5live on MW and BBC R4 on LW.

Try listening after dark, with a reasonable outdoor antenna you should hear a few Spanish stations on MW and if you are lucky possibly the occasional North African station too

Apart from that, MW/LW has become a wasteland.
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Old 27th Sep 2023, 10:07 am   #3
Cobaltblue
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Default Re: Cossor 520 - no stations

The so called internal aerial on these is pretty useless it really requires an external aerial. The internal aerial is a "local stations" aerial.
These also suffer low Q on the large upright wax covered tuning coil making them pretty deaf.

Although these are simple sets they are of their time and capable of pretty decent performance.

This Chassis which is almost identical to the 494 500/501 may have Loctal valves or B8A the Local and B8A sockets can be a pain on these as well IMHO.

Cheers

Mike T
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Old 27th Sep 2023, 10:30 am   #4
Station X
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Default Re: Cossor 520 - no stations

Quote:
Originally Posted by Welsh Anorak View Post
Incidentally it has a Gram input but no corresponding position on the wavechange switch. Do I assume you simply find a quiet part of the band and use it that way?

Thanks!
Yes. That is correct. You should be able to do a "buzz test" at the GRAM sockets.
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Old 27th Sep 2023, 10:33 am   #5
kalee20
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Default Re: Cossor 520 - no stations

I have a Cossor 500, very similar (mine has B8G Loctal valves). Sensitivity is mediocre, the RF/osc tracking is only optimiseable at one point which doesn't help - but sound quality is very good.

Yes, the Gram input basically needs you to tune to a quiet part of the band - it's permanently active. (And conversely, when receiving a station, there's signal-level AF present on the sockets). It's crummy really, and the fact that the detector diode is still in circuit does nothing to minimise distortion, though it doesn't seem to make much difference in practice!
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Old 27th Sep 2023, 10:54 am   #6
Lloyd 1985
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Default Re: Cossor 520 - no stations

I got one of these recently, and I was actually quite impressed with it! Not much on long or medium wave, but I was able to get a fair bit on shortwave, and I’ve only changed the audio grid coupling cap so far!

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Lloyd
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