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[RFI] Intermittent noise, all bands, 2 antennas and 2 sets of finals los

To: rfi@contesting.com
Subject: [RFI] Intermittent noise, all bands, 2 antennas and 2 sets of finals lost
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Tue, 27 Oct 2015 00:54:25 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
I'll try a more appropriate title this time

It's easy to see the relationship when looking back, but remember these problems were spread out well over a year. I'm going from an old memory recalling events, some of which more or less seemed trivial at the time, so some of this may seem disconnected.

Around the first of the summer I noticed a noise that would come and go at irregular intervals. It was kinda like precip static that starts out as a series of pops, that get closer together until they became a low frequency buzz, which quickly goes up in frequency to either end with a pop, or just fade out. Similar, but different is the only way I could describe it and it didn't always sound the same. Something it just sounded like something was arcing. It wasn't really strong either. Two different problems, or one with a personality disorder?

To begin it didn't happen all that often, but as time moved on it happened more often At first it bothered so seldom that I really didn't have any concerns. As time went on, it became much stronger, more often, and downright annoying

I had the matching network fail in the big Diamond 144/440 duo band and lost the VHF finals in the Yaesu 897D. I replaced those finals, or rather sent the rig into Yaesu who had it back to me in short order. I replaced the Antenna with a new one of the same make and model and hooked up my TMV-7A. Looking good.

BUT, about a year later (give or take) I was talking with one of the locals on his way home. He remarked that my signal started getting noisy as if I were a mobile running out of the system. Hmmm, Heat sink was hot, so I immediately shut down. SWR was sky high! Yup! The matching network in the antenna was shot. The general consensus was that I had a grounding problem as in earth grounding, yet the grounds, including the green wire "to the 200A service panel" appeared to be good with all the checking I did.

Over a year ago, my CAT 5 Gigabit network took a strong jolt from a close lightening strike. There were three 130' CAT-5 runs from from the smart switch and router in the basement to the shop. It wiped out both the router and switch as well as the motherboard in that computer. It also welded the run to the socket in the UPS for the main computer in the shop (the one that lost the motherboard). I went wireless, replaced that computer with my back up unit and replaced that storage (four, 4 TB drives) with a 16 TB server in the shack in the house. (Easy to shut down and disconnect.) No more CAT 5 to electrocute my computers.

NOTE: it was several months after the lightening strike that I lost the first antenna. The second antenna failure was nearly a year after that

BTW the computer that lost the motherboard was the biggest and fastest computer I had. The computers have 850W to 1 KW power supplies. Each runs of its own 1.5 KVA UPS.

On what I thought was a completely different, computer problem; when viewing AVI, or streaming video, the computers would hang or do a good imitation of "Max Headroom". Strange...The frequency and severity of this also increased as summer progressed. THAT had me thinking that they must/might be related and the one computer that was the worst offender was the one in the shop, but they all had the problem to a lesser extent and the one in the shop was now wireless. The one in the shop was powered off the original UPS.as were the power supplies for the station in the shop. Remember too that the antenna system ground ties all of the grounds together.

I shut down all the electronics in the shop, switched every thing connected to "that" UPS to the one for the spare computer. Amazing, "Max Headroom" was now silent and the noise on the rigs was gone. I don't know how much of these happenings were related to the lightening strike and how many were related to the UPS. The question comes up as to why it didn't/doesn't trip the GFI. "I think" The output of the UPS is isolated from the line. That GFI has tripped a couple of times, but only a couple of times. It takes only a tiny bit of ground current to trip the GFI. Far less than what it takes to burn out one of those tiny matching networks.

Usually semiconductor fail, either shorted or open at the time of "the event", but I do know that solid state devices can be "hurt" and may, or may not fail at some later date due to having been hurt. So, I don't know if I've seen the last of this, if it's a series of "hurts" propagating from the previous failure(s), or even if they are related to the original lightening strike. What I don't know is if the two antenna failures were related. I'm fairly certain the second one was related to the UPS.

Knowing semiconductor circuits as I do, I fear I've not seen the last of its effects. 2 sets of finals and 2 big antennas, ignoring the computers, this is getting kinda expensive.
Anyone know how to check for future possibilities?

73

Roger (K8RI)

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