Yikes, it has been a while since I got the cavity, but I am now one step away from getting it ready for testing. In the last update, I left you with pictures of the cavity a few days after I received it. I attempted last week to solder the probes to the cavity wall, but even if the solder stuck to the copper plating, it was not strong enough to support the probe, which, when touched, broke the solder pad completely off. Worse, the tinning process with the hot flame ended up taking some of the copper off with it.
Here is a screenshot from the documentary footage of the probe which was attached for all of a few seconds before I touched it again:
(The holes around the circumference are threaded to attach the copper end plate)
A better solution, although more time consuming, is to drill a hole, thread the hole, then add threads to one end of the copper probe and screw the probe into the cavity. (The other end then attaches to the N-to-probe adapter). I bought a tap set (shown below, including the screws) which was needed to mount the N-to-probe adapter but to thread the probe itself, I need two dies (one shown on the right). I need a 2mm die for the measurement probe and a 3mm die for the power probe, and the dies should be here by Friday (nobody in Edmonton carries such small dies as regular stock).
The good news is that if this cavity shows promise, I can have it replated for about $500. Being able to completely dissemble and resemble the cavity without soldering anything will be useful. In the future, when working with cavities, my default will be to try and bolt things together instead of soldering them.
Here’s a cropped shot from the documentary footage as I drill holes to mount the N-to-probe adapter (you can see both the power adapter being drilled and the measurement adapter lower right side):
I have also been talking to vendors about getting a proper continuous power supply that runs on 110v and includes a feedback circuit to keep the frequency as tightly centered as possible. At this point, I’m guessing it will cost anywhere from $5K to $10K for such a device (new), if I can’t make it myself.