The Tenner 10m CW Transceiver
A small experimental CW transceiver using just 5 transistors 
Updated 13.1.08 (schematic added) NEW
Updated 13.11.06

INTRODUCTION

The Tenner is a small 500mW CW rig for 10m.

It uses the OXO circuit for the transmitter and an SBL1 based direct conversion receiver on receive. 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 for a single balanced mixer using a toroid and 2 matched diodes.

I have now roughed out the schematic of the Tenner although I cannot guarantee all values are precise and will check these over when I have a little more time and a brighter light to see with! On the circuit shown there is a switch to select two VXO ranges, but only one is fitted.  

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 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.


SPEC   

TX Power             500mW
RX sensitivity       -110dBm (although not optimised with antenna switch and currently a little deaf using this)
VXO range           25kHz (2 x 25kHz with second crystal)
TX/RX switching   Full break-in

Return to index page