Demonstrating a 3 transistor receiver built for a construction competition. It has just 3 transistors and under 25 components but tunes part of 80 and 40 met…

11 replies
  1. Andy Page
    Andy Page says:

    Peter do you have the plans for it published any where on line? love it fab
    concept for a project for the kids and big kids like me.. Regards Andy
    (2E0CLY)

    Reply
  2. AdmiralHalsey100
    AdmiralHalsey100 says:

    VK3YE, would you like to post a schematic of your “Chopping Board” HF
    receiver please? Is this receiver a Direct Conversion Receiver?

    Reply
  3. vk2zay
    vk2zay says:

    It is always surprising how well those infinite impedance detectors work
    across a tank with just a little bit of LO drive from a nearby oscillator,
    not directly connected. The ceramic resonator makes it super easy and
    stable. I’d be tempted to use a LC VFO and cover the lower-half of HF, but
    it would need a vernier or fine-tune gang/pot. Maybe a subharmonic VFO
    tuning 1.5-2.5 MHz or so, which should be fairly stable?

    Reply
  4. vk3ye
    vk3ye says:

    Alan – it amazes me as well. Why would one bother with a regenerative
    receiver when something like this has as much audio output? The only thing
    is the regen receiver may be a bit more selective but in exchange you lose
    many things eg oscillator pulling on strong signals or antenna blowing in
    the wind. The best of both worlds may be a regen put to the point of
    oscillation plus an external oscillator.

    Reply
  5. BitternThe
    BitternThe says:

    Nice looking radio Peter, sounds like it is pulling in some AM at 4:54? Do
    you zero beat the ceramic resonator with the am carrier when receiving am,
    or just tune it far away so as not to hear any heterodynes?

    Reply
  6. vk3ye
    vk3ye says:

    You can do both. Sensitivity is much better if zerobeat. Without a carrier
    inserted it only picks up a few of the stronger stations.

    Reply

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