Bob wrote:
Hello,

Took the plunge, and purchased a WinRadio Excalibur SDR receiver.
I would like to protect it as best I can.

I do receiving only (30 MHz), and have an end-fed antenna from PAR
outside.
We get a fair amount of lightning in the area, but have never had any
direct hits.

I have the typical ICE lighning arrester at the junction (outside) where
the antenna joins the coax leading to my radio in a room upstairs.
The arrester is connected to a ground rod that I laborously banged into
the soil.

What concerns me most I think is the voltage being induced, possibly, by
nearby strikes.
If anything actually hits the arrester, I doubt that it, or anything,
would survive. Probably more of a "feel-good" kinda thing than anything.

So, let me ask please.

a. Can "nearby" strikes, say 1/8 or 1/4 mile away actually induce
meaningful voltages in the antenna (about 10 feet above the ground,
running horizontally) ? How large ?

Yes.. Some of the voltage is induced because of currents flowing in the
ground, by the way.

The vast majority of power and phone line transients are produced by
induced currents, not direct hits.



b. I try, but I am not always home, or remember always to do so
frankly, to disconnect the antenna when done using the radio. Having my
son do it if I am not around is an exercise in futility.

What kind of "protector" can I put right at the radio to try to protect
against any voltage surges (not direct hits) ?

Put your protection where the wire enters the house. Lots of UL listed
"antenna protection devices" around, use one of them.


c. What about voltage surges coming in via the AC line ?

Not likely to kill your radio, but a whole house transient protector, at
the service entrance, is the best way to deal with it. These days, your
power company may offer it for a very nominal fee (dollar a month sort
of thing)


d. What about static (buildup) charge ?

This is an issue if the antenna is totally insulated from ground. A
high value resistor or inductor to ground will discharge the static from
blowing rain, dust, snow, etc.


e. I've rfead about the Polyphaser line of gadgets. Is one of these
what I possibly want ? They are quite pricey.

That's what you want.



I've also read about using neons back to back, and 10 meg ohn resistors,
etc.
Seems to be a lost of cons to this approach, as well as possible
benefits. Thoughts on ?

That will work too.

Any thoughts on all of this would be most appreciated.

Thanks,
Bob