For Static control, I have a 1 megaohm 1/2 watt resistor to ground from
each side of my antenna. I do this because my balanced antenna tuner does
not have a DC path to ground.

Notice I said STATIC control, not Lightening arresting.

You can use a much lower value. The resistor should be large compared to
the impeadence of your anteanna. So if the antenna is 4,000 ohms, even a
400,000 ohm resistor would be 100 times the antenna value.

KA9CAR




"mike" wrote in message
...
Hey group,

I have a portable radio with no external ground.

Recently I built a PI network antenna tuner in a metal box and
included an output for earth ground. So the outer sheild of my coax
inputs as well as outputs and the variable capacitor frames are on
this ground to earth. The random wire input goes strait to the tuning
capacitor thus needs some kind of static drain off.

I have heard using a neon bulb and a 2 watt 2.2k ohm resistor in
between the inputs and ground would discharge static buildup and give
me some warning of build up conditions.

I am also concerned about limiting the voltage to the receiver front
end to prevent damage. I have heard installing back to back high speed
diodes between the imputs and ground would acheive this.

I understand everything but the diodes. What does back to back mean. I
recall diodes are one way, but which way goes where? Should I look for
a certain type or rating of diode?


Thanks for your help,

Mike