TX on 80-m (L3 heating)

10 April, 2006 

It has been reported that L3 on the KX1's main board can become hot to the touch when using the KX1 on 80 meters at full power (3 to 4 watts). We verified this in the lab. The temperature rises enough after a few seconds of continuous key-down time to cause a decrease in transmit power output and efficiency. The remedy is to increase the number of turns on L3 from 6 turns to 18 turns. This has no negative effect on any other band. Both the KX1 and KXB3080 manuals will be updated immediately to reflect this.

We recommend that this change be made to all KX1s to be used on 80 meters. The change to L3 is best accomplished by removing the KX1's PC board from the case. All that is necessary is to remove the original 6-turn winding and rewind L3 with 18 turns of #26 enamel wire.

If you don't have enough #26 enamel wire left over from the KX1 or another kit, we'll send you some upon request (send your request to parts@elecraft.com ).