On 2023-11-08 16:42, K9HZ wrote:
Most of the commercial antenna tuners for hams (MFJ, Elecraft, LDG,
etc.) are built with fixed components (fixed caps and coils)
*** I have an MFJ998RT kilowatt remote autotuner at the base of my
vertical.
It mostly works well, and magically produces low SWR across most of the
HF bands.
Which is important, because I have a 250-foot coax run.
It is not, however without annoyances. MFJ basically took their
desktop
autotuner and packaged it in a weatherproof case. There is no remote
control -
all I can do from the shack is to interrupt power to it. It has
memories;
once it has completed a tuning sequence for a frequency, it remembers it
and
returns to it instantly.
But if things change up at the antenna - maybe a connection got a
little
corroded, or a bush grew up, or ??? , the tuner does not retune. It
keeps
using the memories, and the SWR at the shack degrades.
The only way I can make it retune is to trek up the hill, remove the
umpteen
screws for the weatherproof cover, and push a sequence of buttons to get
a
factory default. Thankfully that isn't necessary very often.
- Jerry, KF6VB
