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Old 18th Jan 2020, 12:28 am   #3
Vintage_RC
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Join Date: Sep 2018
Location: Twickenham, London, UK.
Posts: 536
Default Re: My next project - the first French transistor radio

I've spent a bit of time playing with the Solistor. On powering up the current was a rather alarming 200mA but his subsided down to 12mA after a few seconds, I think this was electrolytics reforming - it hasn't happened again. I had an earpiece connected in place of the speaker and there was a typical germanium hiss which altered with the volume control, so far so good but no sign of any stations on MW or LW . I set the tuning dial to 300m (1MHz) and using my Tecsun PL660 looked for any sign of a LO signal, encouragingly I found a signal at 1.130MHz (IF is 130KHz). I repeated the exercise on LW and that was OK as well. Going back to the AF side of things I injected a 1KHz sine wave into the volume control wiper and was greeted with a healthy tone in the earpiece. So we have a working LO and audio stage but no sign of stations. I think the next stage will be to inject an IF signal at 130KHz and see what happens. I need to sort out something to provide 130KHz, the little Nombrex I was using won't go that low. I've got a decent signal generator right at the back of the cupboard with test equipment in it, I'll have to dig it out and see if that will go that low.
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