A good gadget for doing this is a simple capacitor tester----like made by Heathkit and many others. Set the capacitor tester for "ceramic and mica" and "leakage test" and connect the antenna side of the Polyphaser to the tester-----the radio side should be disconnected. Now, turn up the test voltage while watching the magic eye or whatever your tester uses as an indicator. The commonly used gas tube or button in most arrestors will break down around 230 volts or so but arrestors are offered with buttons down to 90 volts and much higher than 230. A typical capacitor tester is a very high resistance device in the ceramic / mica leakage test mode and no damage to the gas cell is likely but be careful not to test in the electrolytic mode---arrester cells are designed to pass very high current for a couple of microseconds, usually without damage, but I don't know just what one can stand more or less continuously.
The series blocking capacitor used in some arrestors can also be tested with the capacitor tester---just connect to the radio side of the arrester with the antenna side shorted. I suggest that you use caution here though--I can't remember a guaranteed voltage rating on the blocking cap. ---better look it up before testing. Scott, N6NXI ----- Original Message ----- From: Gary Schafer To: [email protected] Sent: Friday, April 04, 2008 1:26 PM Subject: RE: [Repeater-Builder] Static on grounded feed line system. You need a HI-pot tester to check the protection devices. You crank up the voltage until they show a breakdown and see if it is breaking down at the proper voltage for the device. It will not harm them at all as the current is only a few micro amps.. Polyphaser used to market a small test set they called the FIST. They may still have it?? It was a small automatic hi-pot tester with a meter that read out in Kv. The voltage would rise to the breakdown point and stop. You read the meter for the breakdown voltage. 73 Gary K4FMX ------------------------------------------------------------------------------ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Radioman Sent: Friday, April 04, 2008 8:49 AM To: [email protected] Subject: Re: [Repeater-Builder] Static on grounded feed line system. I replace the Polyphasers at the sites I'm responsible for every two years, or sooner if a direct strike is suspected. Just because they pass RF OK doesn't mean they're still doing the job efficiently. I believe it is cheap insurance even it means replacing a half dozen or more at one site. I have recently heard that there is a new series on the market which may not require replacing except after a direct strike. I need to do more research on those. Maybe someone here has info on those? Harry, W0OZL ----- Original Message ----- From: Paul Plack To: [email protected] Sent: Friday, April 04, 2008 1:45 AM Subject: RE: [Repeater-Builder] Static on grounded feed line system. Sorry for being a few days behind on e-mail, but...don't those gas tubes need replacing eventually? Maybe after 8 years, they've given all once too many times to stay on the job.
