DIY Audio Projects Forum

Help with old Crystal Radio find
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Author:  Blinditis [ 22 Jun 2019, 17:31 ]
Post subject:  Help with old Crystal Radio find

Hello , I bought this crystal radio and I'm unsure of the components ..I'm used to razor pencil type crystal radios but I'm unsure what this is? I get static but no stations on a powered speaker.

Any help will be appreciated thanks. Mark.

Author:  gofar99 [ 23 Jun 2019, 20:35 ]
Post subject:  Re: Help with old Crystal Radio find

Hi, It appears to use a germanium diode as the detector. I did not see a small capacitor on either the antenna or output side which are common. The transformer is likely to be a modest impedance one to feed (step up) a crystal headphone. Often that is omitted and the phones are coupled directly. The coil looks rather large for the standard AM band and could be for long wave use. That would explain the lack of stations. The best way I can figure to determine what you have is put it in proximity of something that will generate a suitable signal. A RF sweep generator would be ideal but you are unlikely to have one. You can often use an existing AM radio and sweep it through the band and see if you get anything. Then you can compute what the crystal one is designed to receive (as a sum or difference of the intermediate frequency of the AM radio at what frequency it excites the crystal set). Other folks might have some better ideas as this is a bit out of my normal field.

Good listening

Author:  Blinditis [ 23 Jun 2019, 22:59 ]
Post subject:  Re: Help with old Crystal Radio find

Thank you bryce....I will try the am sweep and see what is going on , I restore gramophones for a hobby but haven't been near a crystal radio since 1974 ? Ugh I'm getting up there..

Author:  gofar99 [ 24 Jun 2019, 11:01 ]
Post subject:  Re: Help with old Crystal Radio find

Hi Cool, I see I spelled my name wrong....must be age related

Good listening

Author:  Blinditis [ 24 Jun 2019, 22:21 ]
Post subject:  Re: Help with old Crystal Radio find

Hey Bruce , I know a Bryce so it seemed pretty normal ... I tried a few sweeps back and forth with my portable am radio and it seems pretty dead..going to get out my early shortwave and try again tonight. I'm going to see if anyone knows wth this even is before I make it a razor pencil crystal and rewind the coil and buy parts.

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