26-06-2016, 08:51 AM
Hi.
It's been a few months since I posted on the topic.
Since then and after some recuperation from my heart bypass I have been trying different things.
All sorts of different detectors have been tried from germanium diodes, silicon, germanium transistors to those supposed wonderful ADL110900 Mosfet devices.
The best being a selection of germanium diodes. The frame itself seems best with a decent primary, thinner wire reduces output and how you couple the secondary also makes a difference.
There is also a way of improving output very slightly on the weak stations, that is by wiring the secondary of the loop to the secondary of the toroid in series, for some reason it works, I've experimented with different turns ratios on the toroid but output can be a trade off for selectivity and vice versa.
I think now it is at its optimum and I actually use it as a tuner for my Mullard 3-3 amp, the audio quality is outstanding, biggest problem is its size, hardly portable.
Now to baffle the boffins!! This will actually transmit, if you tune into a station and then tune a radio into the same frequency and have it close to the frame aerial it will modulate the carrier if you speak into the phones. It does work and was demonstrated to Andy last week.
Since then I have used the frame main winding connected to a simple RF oscillator and tried it this way, it works extremely well with superb audio quality albeit with only a few feet range.
I was actually thinking of making a smaller one for a pantry transmitter.
All good fun.
It's been a few months since I posted on the topic.
Since then and after some recuperation from my heart bypass I have been trying different things.
All sorts of different detectors have been tried from germanium diodes, silicon, germanium transistors to those supposed wonderful ADL110900 Mosfet devices.
The best being a selection of germanium diodes. The frame itself seems best with a decent primary, thinner wire reduces output and how you couple the secondary also makes a difference.
There is also a way of improving output very slightly on the weak stations, that is by wiring the secondary of the loop to the secondary of the toroid in series, for some reason it works, I've experimented with different turns ratios on the toroid but output can be a trade off for selectivity and vice versa.
I think now it is at its optimum and I actually use it as a tuner for my Mullard 3-3 amp, the audio quality is outstanding, biggest problem is its size, hardly portable.
Now to baffle the boffins!! This will actually transmit, if you tune into a station and then tune a radio into the same frequency and have it close to the frame aerial it will modulate the carrier if you speak into the phones. It does work and was demonstrated to Andy last week.
Since then I have used the frame main winding connected to a simple RF oscillator and tried it this way, it works extremely well with superb audio quality albeit with only a few feet range.
I was actually thinking of making a smaller one for a pantry transmitter.
All good fun.
