I recently finished building a QRP xcvr which worked great on the receive side but had no output. I did the best troubleshooting I could do with the simple tools and skills I had (I’m not an engineer), but still was unable to resolve the problem. I exchanged several emails with QRP Bob from Wilderness Radio. He was fabulous and got me thinking about how to identify the problem. My problem was that I lacked the proper tools and expertise.
After many days, I realized I had hit a wall.
It was time to put a call out to the hams at the Palouse Hills Amateur Radio Club, where I’m a member. In less than 24 hours I had several offers for help. In the end Ron, N7CE, hooked my rig hooked up to an oscilloscope to diagnose the problem. It appeared to be a faulty JFET just after the xmit mixer section. I removed the JFET to confirm it was defective, but it seemed fine when tested outside the circuit. Ron reinserted the JEFT onto the circuit board and tested again. The JFET and rig worked fine! Apparently it was a cold solder joint. Problem solved.
This was a great experience, but not just because the problem was resolved. In the bargain I learned a bit more about how to troubleshoot these kinds of problems, discovered I had done a pretty good job building the kit (just had one bad solder!), realized I need a better multimeter on my bench, built an RF probe and QRP watt meter as part of my efforts to troubleshoot the problem.
Now I can’t wait to log my first contact on my new rig. Not to mention that I can’t wait to take on my next project.
And those are just some of things that make Ham Radio such a great hobby.