On Thu, 16 Jul 2009, Chuck Kelsey wrote: > A group here had storm static just like you and a 2-meter machine. It > would start to build up, then discharge rather noticeably. This would > repeat until the storm arrived. The antenna was a fiberglass > collinear. Spoke with the local GE sales rep who had experience with > this problem. His advice was to not use a fiberglass antenna and go to > an antenna with each element at ground potential. That solved the > problem we had. > > I have to wonder if you don't have something adequately grounded or > bonded or if the ground system is inadequate for the site.
My father built a device which functioned as a static voltmeter. The exact design eludes me at the moment, but when it was connected from the station ground bus to an ungrounded 40-ft horizontal dipole, it would show the current difference of potential. Now, this wire was suspended about fifteen feet off of the ground, and surrounded by 75-ft pine trees. Yet it was common during a storm to see more than 10V across the terminals. You don't feel the field because you're a part of it. The lesson here is that unless there is a DC-short on the antenna input, the radio may see appreciable voltages. The Polyphaser will attenuate anything above a certain voltage threshold, say 100V. If you have a dedicated receiver, you may consider additional methods of current limiting the receiver input. In the past, Motorola used a 6.7V zener diode in parallel with a neon bulb to limit the voltage at the front end (Low-band Mitrek). The modern GE Orion and M7100 radios use a series of diodes to effectively limit power as well. This is what keeps the radios from going "poof" when two cars are side by side and one reaches down and transmits. -- Kris Kirby, KE4AHR Disinformation Analyst
