Topband: More - lightning protection on 4 sq

[Harold Smith]

> Greetings everyone. . .
>
> I received several responses to my email regarding installation of 
> lightning protection on my 160 meter four square.  Several people 
> suggested I put a Polyphaser on the coax output of the Comtek box. . .the 
> coax going to the rig.  In my case, the lightning did not enter the Comtek 
> box via the coax going to the rig (it's buried with a Polyphaser on the 
> rig end of the coax).  Lightning came into the Comtek box from one of the 
> vertical elements of the array itself.
>
> Several people suggested spark gap arrestors, shorted 1/4 wave stubs, or 
> choke shunts (ala Array Solutions) on the elements.  These approaches 
> would, no doubt, help.  Unfortunately, I didn't get a firm answer to the 
> real question.  Will the addition of the standard DC blocked Polyphasers 
> (basically, a big series cap) installed on one end of each coax phasing 
> line, alter and destroy the correct phasing of the array?  A couple of 
> people said they thought it would but weren't sure.  It would seem that 
> inserting a large amount of C in series with the phasing line would have 
> to alter its electrical length. . . and ruin the phasing in the process. 
> If so Polyphasers wouldn't work, leaving the spark gap, stub, or choke 
> solutions.  Is my thinking on track?
>
> 73 . . . Dave
> W0FLS

Dave,

The Polyphaser lightning arrestors are not just a capacitor. It is not a big 
capacitor.

On the antenna side is a gas discharge tube to ground and it has a series 
capacitor to the equipment. The purpose of the capacitor is
to prevent the breakdown voltage (90 to 100 volts) of the spark gap from 
reaching the equipment. The case MUST be connected to a GOOD earth ground.
Without a good ground they or any other device will do very little to 
protect, if at all.

I did a simple test with a MFJ 259B analyzer and found the following with a 
50 ohm resistor.

Reading at 1.8 kHz with out Polyphaser.....Z=50 ohms.... X=0 ohms
                                    with Polyphaser.....Z=50 ohms.....X=5 
ohms

If I were you, I would give them a call and talk to one of their engineers. 
You can find them at www.polyphaser.com.

I hope that this helps.

73  Price W0RI