Batboard

Hello I was going to see if any body knew of a really good arrestor for vhf I guess with N connectors or uhf either one. I have several new Andrew arrestor plus "t" series but all of them are for 800-2200mhz. if any of you all know where i could get one or could just let me know what to look for it will be going on my 7/8 coax. Thanks in advance!

Polyphaser. Do keep in mind that the Polyphaser units do have a SHELF LIFE... picking up some at a hamfest is a bad idea. Buy them new and mark them for replacement at X date.

N connectors. UHF connectors have no place on Heliax (or at a real site, but that's a religious argument).

So do what type connectors do you recommend The
DIN. thanks

DIN is used a lot in Europe and in North America for PCS freqs (1800 MHz). The connectors are expensive. N connectors are fine for VHF.

What is this about a shelf life for Polyphasors? What is it in there that goes stale? Or were you meaning "hit" life? From taking a few apart, there is a tiny gas discharge tube in there. Does it lose its seal? Please elaborate!

RF Dude.

Go with the N-type connecters.

glock318 wrote:So do what type connectors do you recommend The
DIN. thanks

I think tvsjr is saying go with the n-type connectors.

tvsjr wrote:N connectors. UHF connectors have no place on Heliax (or at a real site, but that's a religious argument).

Note the period after "N connectors"

Ok, bump the last thing i said. I will let you know what i have you let me know what you would recommend. I have a 340' tower with a vhf celwave dipole on the top and i have a hard line 7/8. The dipole celwave has a uhf female connector on it, My duplexer has a N female in it. so what would you recommend, For a lighting/surge arrestor and connectors. Thanks in advance again.

Don't forget a good coax ground also. This is overlooked many times in ham use. I see many big $$$ ham setups with only a Polyphaser or similar unit, but not coax ground at the top and bottom.

Thanks I have 3 ,7/8 andrew ground kit for the coax, My freq is in the 154 range how much of a deffrence will it make if i use one of the andrew t arrestor i have for 800-2200mhz, I know it will make some noise but how much will it really make?

Yes, use N-connectors. DINs are very expensive and most people don't have the tools. My rant was against UHF connectors, which aren't worth a damn above 30MHz.

Jim is correct, although it should be expanded to a good ground, period. Your coax, shelter, cabinet, everything should be properly earthed through ground rods/chemically enhanced electrodes, a halo ground, etc. The effectiveness of the ground should be checked using a clamp-on tester (fast but spendy... the units look like an amp clamp on steroids (they have a sending and receiving loop in the clamp) and cost about $1200) or the fall-of-potential method.

Polyphasers do have a shelf life, although it's not discussed very much. You will notice a drop in RF performance (greater insertion loss) after they sit for too long, even if they haven't been exposed to lightning. I'd replace them every 5 years as part of a comprehensive test of your grounding system. Although, more than likely, you'll toast them before then due to lightning. However, if you get NOS units, you can run into trouble.

If you want to use the Andrew arrestor, you need to check it on an analyzer to see what the insertion loss and SWR turns out to be. Polyphasers are <$100... why not just buy the right stuff? It's cheap compared to everything else you're dealing with.

Thanks, Really appricate it, Thanks again for your time! Josh

Could you point me to a link at Polyphaser, or explain why they have a shelf life?

I have heard this many times before, that even a new in package Polyphaser is only good so long sitting on the shelf. But what goes bad, degrades, with age?

Or save your self some bucks and use two 1/4 wave long shorted coax stubs spaced a 1/4 wave apart.

You can build this out of two N type T pieces. When you make up the stubs leave plenty of coax inner exposed after the short and use that to connect to your station ground.

If you use decent crimp connectors and tools it’s about 30 minutes work.

Thanks! I'll Try that!

I would ike to find out about the PolyPhaser "shelf life" too. I have never heard of this and I have units in the field since the late 1980's that work fine.....

I would like to hear from who ever came up with this limited
life issue. Just where did you obtain this information from?

There is no mention of this topic on the Polyphaser site.

I have been in the 2 way field for better than 35 years now
and use these devices all the time. I have never heard
anyone ever mention that there is a limited shelf life.

What I will say is that there is a finite life of the surge
protectors when it comes to the number of hits and the
intensity of the surge they have undergone. Every surge
that they take does do some electrical damage to the
protector. Every time they do fire, you have caused the
lowering of the voltage point at which they will fire the next
time.

Polyphaser does have a high voltage test unit for checking
to see if the units are still functional. However they caution
using it to make a regular testing of their units. Again, each
time the surge protector is tested, fired or sustains a surge, it
does some measurable damage to the gas tube. You just can't
tell how much.

Most of the major carriers take the stand that if the site has
taken a major hit, all the surge protetors should be replaced.
It is cheaper to mass replace the surge protectors rather than
have the site go down.

Jim

loband wrote:I would ike to find out about the PolyPhaser "shelf life" too. I have never heard of this and I have units in the field since the late 1980's that work fine.....