Last night was my second “serious” TX test on 136 kHz, transmitted Opera32 mode after an upgrade to the matcher.
To tune the antenna on 136 kHz I’ve build a couple of inductors over two hand cleaner soap bins. The first one was wound with enameled copper wire of about 1 mm diameter, the second with PVC copper wire of 1.5 mm diameter.
The first has an inductance of 2.2 mH while the second is around 400 uH.
Inserting one bin into the other I’ve reached the needed inductance to work with my antenna on 2200 meters.
Moving up and down the two bins I’ve reached a coarse value just to use my variometer for tuning. The maximum value that I can reach is about 4 mH.
In the next photo the final layout of entire matching system for 630 and 136 kHz.
From left: remote controlled variometer (for fine tuning), matcher, 136 kHz tunable coil. The next step will be to remote switch the two bands from my radio room.