Hi Paul,

sorry to read that. Have pity on the poor FETs!

You mentioned that the antenna resistance is gradually decreasing (i.e. improving) during longer transmissions. I often see that effect here, with the current rising by say 20 % during the first few minutes. I've put it down to moisture or dew around the coil and insulators (tiny little polycarbomnnate pencil tubes), which evaporates as things warm up. It is more prominent during cold damp weather, and much more so with the very high antenna impedance at VLF than at LF.

Good luck,
Markus 


-----Ursprüngliche Mitteilung-----
Von: N1BUG <[email protected]>
An: [email protected] <[email protected]>
Verschickt: Fr, 23. Nov. 2018 22:12
Betreff: LF: No 2200m TX tonight

No transmissions from me this night. The little amplifier has died.

I think it may be related to this resistance change in the antenna

which is getting worse and worse.

I'm going back to MF for this night, sorry!

73,

Paul