Miscellaneous Stuff
"The Basics"
Need a DC power line filter?
I use this with my 100
watt HF mobile and 45 watt VHF/UHF system and it works great!
The core that I used was
one with an I.D. of 2 1/2".
Considering
mobile operation, using SHORT FAT BRAIDED ground leads helped
tremendously!
The shorter and
fatter the better, yes they DO work, and don't use just a few, use MANY!
I've proved it
myself with HF SWR tests. Of course, the the antenna was resonant and
using
an LDG mobile
tuner, every time I added another braided ground strap, the tune up was markedly
better.
BTW...
In my opinion the LDG auto tuner works fantastic! No "plug" just my
honest experience.
Tom
WA9WSJ...
Need
a screwdriver antenna motor control?
I did, so I designed this
one. Some systems use a simple resistor in series with the motor power
leads.
Not the best way
to do it. This limits the current and thus the motor torque. My motor was so
weak and
wimpy that it barely
would move the coil with its plexiglass cover, in fact it had stalled a few
times so I
came up with this system
and it works great! It provides the proper voltage regulation and lets the motor
have all the current that it
requires. Now it's very difficult to even slow down the motor! Note: you can
use
any voltage motor, (up to
12 volts), with this system. Simply adjust the pots for the voltage which your
motor needs!
In my
application it has a maximum speed up/down control for rapid traverse and a reduced speed up/down
control for fine tuning the SWR. I set the
max speed adjustment, R2, for the max voltage which the motor was designed for.
The reduced speed
adjustment, R3, was picked to reduce the 'overshoot' when fine tuning. I found
some
cool center off rocker
switches and they worked out great!
The pass
transistor must be mounted on a heat sink. I used the one in the schematic
because I had it laying
around, any NPN that will
handle the current you need should work fine.
