10m Tenner CW QRP

Small experimental CW 500mW transceiver using just 5 transistors

The Tenner uses the OXO circuit for the transmitter and an SBL1 (or similar) double balanced mixer based direct conversion receiver. TX-RX offset is around 600-800Hz when the key is pressed, so no special RIT circuit is included. The receiver is a decent one with a respectable performance for something this simple. If the SBL1 or similar is not available it could be substituted with a single balanced mixer using a toroid and 2 matched diodes.

I have roughed out the schematic although I cannot guarantee all values are precise.

Note that the crystal uses a 28.06MHz fundamental crystal - NOT 3rd overtone. These are a little harder to find but this gives more pulling range. Even greater pulling range can be achieved with a small inductor in series with the crystal, or 2 crystals in parallel, but watch out as chirp may become excessive and the difference between TX and RX frequency less well defined.

This is a basis for experiments - don't take the values as optimised. Have a go yourself and adjust the circuit to improve it further.

The Tenner has worked lots of DX including many transatlantic QSOs.

With cycle 25 getting into gear, 10m should be getting better again for several years.