Hello Paul,
See the circuit of the M0BMU tuning meter. In attachment.
This device is useful for itselfe. Over the years i built 3 of them :-)
You will always see if your antenna has a capacitive or an inductive
component, i.e. if you need more L or less L. This is MUCH better than
an SWR meter, at least on LF!
With the phase meter part, you can steer the circuit that steers the
motor. I can give you the circuit if you like.
I finally need an alternative to Dropbox which became obsolete a year
ago. It was very comfortable to share files, i.e. generate and paste a
link into an email. I can upload any file to the uni server.... I know,
there alternatives on the Raspi but my time is limited too :-)
73, Stefan
Am 21.02.2018 22:26, schrieb N1BUG:
Hi Stefan,
You need an automatic variometer. A phase meter that steers a motor
which turns a variometer coil inside your main coil.
On LF i had a very high Q system and has to use such an application. It
worked perfectly over years.
That is a very interesting idea. I wouldn't have any idea how to build
something like that, but it would be useful. If not that, at least I
need to devise some kind of high SWR shutdown for the amplifier. I
lost one FET already and it will surely happen again.
I need to make a few small changes to the coil and variometer. It just
has enough tuning range for dry conditions. When there is rain or ice
I cannot tune far enough with it. I think I chose the wrong gear motor
to turn it also. It works fine but the tuning rate is very slow. I
should use a motor with more RPM. :-)
73,
Paul
LFtunemeter.pdf
Description: Adobe PDF document
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