Alex@rtnVFRmedia Suffolk UKAug 9, 2023
This is why #AM #radio is worth keeping - I tuned into #RadioCaroline using an 18m wire antenna run around the outside of the building, a 330 uH inductor and a military surplus CV7130 (OA91) germanium #diode (I had to order these from a place near Brighton selling NOS vintage components, diodes sold on Amazon as "Germanium" didn't work). The output of the detector diode is fed into the line in of a desktop PC (the metal case of which also provide the earth for the receiver)
Show threadAlex@rtnVFRmedia Suffolk UKAug 9, 2023

I had to turn off the LED security light as it was a source of QRM (interference), and its not the most selective of receivers; there is a BBC station in the background - but it works, with just two main components (you could also listen to it with a high impedance earphone, or if an audio transformer is used some walkman earphones)

#radio #electronics

Show threadAlex@rtnVFRmedia Suffolk UKAug 9, 2023
A heads up to anyone who is considering trying to make one of these - this design is affected by the capacitance of the long wire antenna with respect to earth - and cheap LCR meters from China (although way more affordable than such kit was in 1980s) aren't that accurate - so you can only use online resonant frequency calculators as a guideline and will have to experiment with the component values (but a pack of those green inductors that look like resistors is cheap)
Show threadAlex@rtnVFRmedia Suffolk UK

#RadioCaroline is now back on 4kW and broadcasting #RadioCarolineNorth from the #RossRevenge (they have an extra day of broadcasting due to the fundraiser) - the #crystalradio (now using a 220 uH inductor and 165 pF variable capacitor at around 78 pF for best tuning) receives the signal good and strong with quite decent volume to the PC line in (this video is taken using the mobile phone microphone, there is 0 amplification or soundprocessing)

#radio #OffshoreRadio #Suffolk

Aug 11, 2023 at 6:57pmWeb
Show threadAlex@rtnVFRmedia Suffolk UKAug 11, 2023

I got out the soldering iron and built a slightly tidier version of the #crystalradio circuit which works (despite being out of practice with soldering, and having to use the lead free stuff)

#radio #RadioCaroline

Show threadAlex@rtnVFRmedia Suffolk UKAug 11, 2023
I am quite pleased with how this turned out - there isn't anything on MW with a strong enough signal to be received on a crystal set that I would want to listen at present to other than #RadioCaroline (only other stations seem to be sportsball from the BBC) so even with the limited tuning range of this circuit it does exactly what I want it to (and with surprisingly good sound quality!)