Tomorrow starts the RAC Canada Day Contest. I intend to maintain a presence in this context as VA3PCJ QRP. I will likely participate from my QTH with semi-portable equipment: an ICOM 703+ with FL 52 A 500 Hz filter, set at 5W maximum, with a 45′ wire endfed via an Elecraft T1 tuner remote, a toroidal choke and a 4:1 homebrewed unun. The problem is that the Elecraft T1 is refusing to tune. It failed towards the end of Field Day and has refused to work ever since…
I opened it up and noticed that the BNC female, PCM mount connector for the antenna was wobbling sideways. This connector is soldered to the PCB mainboard in three places. On closer examination I noticed that the two large metal legs of the connector were moving inside the solder. The following picture shows the bottom of the main board with arrows pointing at the soldering points that were loose:
I re-soldered both points and the T1 is now in operation and should now be ready for the RAC Canada Day Contest.
However, I wonder what may have caused the legs of the connector to crack open inside the solder that was attaching them to the board. One possibility is physical stress (but it has not been knocked against anything and the short coax towards the antenna has not been putting any stress on the connector). Alternatively, I wonder whether the tuning may not be causing enough heat at the connector as to melt the solder. I doubt this since I never tune with more than 3W output and actual operation is never with more than 5W at the TRX output (as measured with an Elecraft WII meter). Nevertheless the antenna in the QTH is a “random wire” of abt. 45′, which for some bands may develop a considerable current at its feed point. Of interest was the fact that the similar connector for the TRX input/output remained perfectly soldered.