Later today, all being well, I intend to finish the rebuild of my loop for 10m.
I have still to decide on WSPR or FT8. Before doing it, I shall try to (roughly) cut the coax capacitor to close to the correct length, having found out what capacitance I need from the online loop calculator.
My capacitance meter that has not been used for about 7 years! The battery probably needs replacing! I hope it has not leaked.
: The gods are with me! Some time ago, I must have removed the battery to use it somewhere else. I just put a new battery in and the capacitance bridge is working fine. According to my calculation I need about 43pF with a 0.6cm thickness pipe with a circumference of 2m. I shall recheck the pipe cross-section. It is thin bore copper pipe used in central heating systems. If I cut the length slightly long, I can snip a bit off until it hits resonance. The very most I can run is 20W (most times 500mW WSPR or 2.5W FT8) so I am unlikely to have problems with high voltages. In the past I even used a dead ordinary 365pF air spaced variable without issues in a loop antenna.
The loop is now finished and operational. In the end I decided on FT8 and used a 365pF airspaced variable to get to frequency. It is very
sharp! This is a good sign. It seems a few dB up on the other loop judging by local reports. Using the airspaced variable C means that the loop antenna can be used on other bands. The photo shows the completed loop. It was much
harder than I expected. Years ago it would have been trivial.
Just 2 locals have spotted me so far today on 10m FT8 TX with my 2.5W to the better indoor loop antenna.