ANTENTOP- 01- 2010, # 012

An 80m CW Valve Transceiver

Igor Grigorov, RK3ZK

Credit Line: Sprat # 82. 1995.pp. 22-23

It is possible to build this transceiver in one evening using surplus parts. It has a sensitivity of near 5- microV and output power on 3.5- 3.6- MHz near 1-Wtts. The RX/TX changes the function of V3, the Mixer and Power Amplifier. L3 provides tuning in the transmit and receive modes.

I used an old cabinet from a valve broadcast receiver, also using its power supply and audio transformer.

If L1, L2, and L3 are tuned for the band, the transceiver should work straight away.

Parts:

RL1 and RL2: Old Telephone (60- V) Relays

TR1: Audio Transformer from old broadcast receiver

L1: 40 turns 0.5mm wire on 20-mmformer, winding length 20mm

L2: 20 turns 0.7mm wire on 20mm former, winding length 20mm

L1 and L2 were wound on old plastic shotgun cartridges

L3: 17 turns 1mm wire on 50mm former, winding length 50mm

L3 was wound on a glass

RFC1: 400 turns 0.2mm wire on an old plastic pencil 8mm diameter

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