Topband: Oscillation in Narrow band tuned antenna.

[Richard (Rick) Karlquist]

On 1/13/2021 3:13 AM, Rune Øye wrote:

> I have been told that Oscillation in Narrow tuned antennas can occur and
> make damage to your equipment, radio or amplifier. It is really the first
> time I have heard about this potential issue.  On 160m band, I use a

Can you give us more details on this theory?  I've never heard
of it.  Maybe it is something that only applies to modern LDMOS
devices?

> Reason for asking is that I have burned the final transistor in my radio
> and the final FET`s in my PA is broken. It all happens “out of the blue”.

The first question I would ask is whether you have a shunt RF choke to
provide a DC ground for the antenna.  If you do, verify that the
connections to it are reliable.  I mounted a backup RF shunt in a
little metal box with RF connectors that hangs off the output of
my radio to make sure static never blows up the radio, no matter what
antenna I connect it to.  This was after I left the radio connected
to a dipole that didn't have DC short across it and blew up the first
transistor in the receiver.

> 73
> Rune LA7THA
> _________________

73
Rick N6RK