Ten Tec Argonaut 509

The Argonaut has enjoyed a cult-like following among the QRP crowd. While not a particularly sophisticated transceiver, it provides solid performance and it is easy on battery drain. The receiver will run for weeks on a couple of lantern batteries. The receiver is "hot" enough and uses dual-gate Mosfet transistors in the receiver. The transmitter will put out about 2 watts on most bands. SSB quality is OK on transmit, but in the interests of successful QSO's, some sort of speech processing is in order. The receiver is a superhet design unlike the direct conversion receiver used in many QRP transceivers.

I have no idea of the number of these rigs manufactured, but there must have been a bunch of them. The 509 design gave way to more sophisticated successors. Still, the Argonaut 509 is a good example of a successful design that is still in use by QRP enthusiasts today.