004: 50MHz AM 40mW transceiver (super regenerative)

50MHz AM transceiver, 40mW mono-channel, 42-60MHz super regenerative, sensitivity -12dBµV, DC9V。

One day, I recalled super regenerative receiver (12AU7) that I made in old days. A nostalgic desire sprang in the super regenerative receiver, and I wanted to make it in solid state this time. To know the condition of propagation around 50MHz, I set the receiving frequency range to 40-60MHz. The RF amplifier of 15dB gain is provided so that the oscillation energy is not radiated from the antenna. The sensitivity is very good enough as a monitoring receiver, though SSB and CW cannot be detected properly. When sporadic-E appeared, not only amateur signals but also the TV signal from China, Australia, New Zealand and the Buzz sounds from Russia, etc. were able to be heard.

Then I thought it’s a good idea to make an AM transceiver with it. Mono-channel crystal controlled QRPPP transmitter with a modulator was installed soon. As this is a base modulation, the modulation depth changes greatly by the load tune of collector. You should tune the final tank circuit monitoring the modulated signal by yourself. I received a report from JA0BZC of my local, that modulation is nice. Making was in 2010.

50MHz AM transceiver, 40mW mono-channel, 42-60MHz super regenerative, sensitivity -12dBµV, DC9V




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