Polyphaser failure

[K6GBW]

Happy New Year! We started off right with a Polyphaser failure. I went to my radio for a morning net and my SWR went through the roof. I switched to a back up antenna and soldiered on, but later I started investigating the problem. I ohmed out all the coax and checked the antenna itself and everything seemed good. Then I literally got down to the Polyphaser as a possible culprit. I took it out of line by placing a barrel connector in line and voila, no issues. I replaced it with a spare but the funny thing is I don't recall any near by lightning strikes or other weird issues, like high winds or driving rain that could have caused a failure.

Has anyone ever had a Polyphaser fail for no apparent reason? Can Polyphasers fail from cumulative use? Should I just treat them as a wear item and keep a few in stock?

Thanks and 73,

Brian

 

[prcguy]

Happy New Year! We started off right with a Polyphaser failure. I went to my radio for a morning net and my SWR went through the roof. I switched to a back up antenna and soldiered on, but later I started investigating the problem. I ohmed out all the coax and checked the antenna itself and everything seemed good. Then I literally got down to the Polyphaser as a possible culprit. I took it out of line by placing a barrel connector in line and voila, no issues. I replaced it with a spare but the funny thing is I don't recall any near by lightning strikes or other weird issues, like high winds or driving rain that could have caused a failure.

Has anyone ever had a Polyphaser fail for no apparent reason? Can Polyphasers fail from cumulative use? Should I just treat them as a wear item and keep a few in stock?

Thanks and 73,

Brian

If its outdoors they are not water proof. Otherwise I've never heard of a non lightning failure. You can open them up to inspect the innards and ohm out the bad part or path.

 

[mmckenna]

https://www.polyphaser.com/Content/WhitePapers/ddad5dcc-e32d-477d-8d47-82d5e6015c01.PDF

I think Polyphaser used to make/sell a tester.
I found it easier to just keep a few spares in stock.

 

[RFI-EMI-GUY]

Hmm; Polyphaser has so many models. There are models with a gas cartridge that fires at some specific voltage level. Those you have to be careful not to exceed a certain power level and VSWR. Then there are DC blocked ones where a series capacitor determines the low frequency cutoff, VSWR. Those could fail open. If you have an antenna that does not have a DC return you might have precipitation static firing the gas cartridge. Failing all that you must have had a strike and it did its job.

 

[wwhitby]

I've had one of two L-COMM lightning arrestors fail before, giving the same symptoms as you describe. The arrestors are both housed in a sealed, waterproof box outside, so it wasn't water that caused it to fail and I hadn't suffered any lightning strikes. I swapped it out with a spare I had bought for another installation, and I was good to go. What is strange is that the other arrestor is still working fine after 7 years.

 

[KevinC]

How do people know they didn't have a lightening strike? If your SPD did it's job the only indication may be a bad...SPD. Maybe it was a transient voltage surge from something other than lightening or ???

 

[K6GBW]

I dunno, maybe it was near by lightning. We did have one come down about a mile away, at least that I saw. The Polyphasers are outside but the are under an eave on a ground rod and I have them covered with a large plastic bucket. Even in hard rain they don't get wet. I guess it's a mistery. I've only had the Polyphasers on there for about a year. Before that I just had coaxes grounded with a bulkhead connector, but when I got my IC-7300 I felt like the receiver on it was just more delicate, so I installed the Polyphasers. I'll just order a couple of more to keep on hand.

Thanks everyone.

 

[prcguy]

I dunno, maybe it was near by lightning. We did have one come down about a mile away, at least that I saw. The Polyphasers are outside but the are under an eave on a ground rod and I have them covered with a large plastic bucket. Even in hard rain they don't get wet. I guess it's a mistery. I've only had the Polyphasers on there for about a year. Before that I just had coaxes grounded with a bulkhead connector, but when I got my IC-7300 I felt like the receiver on it was just more delicate, so I installed the Polyphasers. I'll just order a couple of more to keep on hand.

Thanks everyone.

What model is it?

 

[RFI-EMI-GUY]

I dunno, maybe it was near by lightning. We did have one come down about a mile away, at least that I saw. The Polyphasers are outside but the are under an eave on a ground rod and I have them covered with a large plastic bucket. Even in hard rain they don't get wet. I guess it's a mistery. I've only had the Polyphasers on there for about a year. Before that I just had coaxes grounded with a bulkhead connector, but when I got my IC-7300 I felt like the receiver on it was just more delicate, so I installed the Polyphasers. I'll just order a couple of more to keep on hand.

Thanks everyone.

Is that lightning rod grounded to your utility ground?

 

[K6GBW]

The Polyphaser model is the basic IS-50UX CO model. Yes, the ground rod is an 8 foot rod driven right outside the radio room entrance. They I have a copper plate that the Poly's are mounted to. The rod is connected to the home ground system, which was recently redone to add two more ground rod's so the house has a total of three, plus the one at the radio room and they are all connected.

I also had them install a surge protector for the AC drop.

 

[K6GBW]

Update; I'm fairly certain I found the cause of the Polyphasers demise. I'm having an in-ground swimming pool demo'd and the crew doing the fill work have been using a compactor. When I went out and touched my ground rod the amount of vibration was suprisingly strong. I suspect the polyphaser was damaged from the intense vibration. I've unbolted them and I'll keep them unbolted until the project is done.

A side question I have is about static disappation. In my area we have very little lightning, but we do have frequent hot dry wind. I've read that the Polyphasers don't drain static but that Morgan Mfg. arrestors do. Does anyone have any experience with this? Would I be better off with the Morgan's for my desert like environment?

 

[WA0CBW]

Have you tried connecting the polyphase to a dummy load and checking the SWR? Does it still show a high SWR?
Bill

 

[prcguy]

Update; I'm fairly certain I found the cause of the Polyphasers demise. I'm having an in-ground swimming pool demo'd and the crew doing the fill work have been using a compactor. When I went out and touched my ground rod the amount of vibration was suprisingly strong. I suspect the polyphaser was damaged from the intense vibration. I've unbolted them and I'll keep them unbolted until the project is done.

A side question I have is about static disappation. In my area we have very little lightning, but we do have frequent hot dry wind. I've read that the Polyphasers don't drain static but that Morgan Mfg. arrestors do. Does anyone have any experience with this? Would I be better off with the Morgan's for my desert like environment?

The Morgan might be better for bleeding off static electricity. You can add a very high resistance from coax center to ground inside a Polyphasor like 250k ohm to 1 meg ohm or add a .75 to 1uH choke which will disappear at HF but otherwise ground your antenna. The resistor or choke are fine in a 50 ohm system where the antenna is near 50 ohms where you transmit. You have to be careful adding a resistor or choke in a random end fed where the impedance can vary from very low to very high impedance as the resistor can compete the antenna for power if its really high impedance like multiples of a half wave.