On 12/7/2025 4:46 PM, David Decoons wrote:
Hi All,
This had been working fine for well over a year and just started a week ago.
Many years ago, I had a gig driving around Chicago fixing sound and
video problems, often in complex systems. When something stopped working
that had long performed just fine, the first question to ask is "What
has changed?" Called to fix the sound system at Wrigley Field, the
first question I asked was "what work has been done around the park
recently?" and start looking for problems in wiring there.
In other situations, think about what might have failed in your station,
both in the shack and your antenna system. One thing that comes to mind
is common mode current in the feedline caused by some form of imbalance
in the antenna, the feedline, and matching on either end.
That common mode current makes the feedline part of the antenna. That's
why a serious common mode choke is needed at the feedpoint of our
antennas. But antennas like yours cannot be effectively choked.
New issue popped up where RF out on 80 meters (about 1000 watts) into an
"optimized" G5RV is causing the fiber gateway (Ubee WiFi 6E) to lose Internet
connection and go into a reset condition after the RFis no longer present.
The antenna is about 60 feet from the fiber gateway. Ladder line goes into coax
(no balun), then 50 feet of LMR400 Times Microwave coax to my 2x8 4O3A Antenna
Genius.
Antenna Genius, Tuner Genius, Power Genius and Flex radio all in a server
cabinet in the garage 1 floor below the fiber gateway. Everything in cabinet
ground to a copper buss then #2 to ground rod about 12 feet away.
So any common mode current on the feedline is going to light up that
gateway.
Network cable from Ubee fiber gateway to Asus mesh router is wrapped 6 times through
a 2.4" mix 75 ring (F240-75) with no turns overlapping. Power cable to Ubee
fiber gateway has 4 wraps through mix 75 wall wart ring.
Wrong ferrite material for HF. The ONLY ferrite material suitable for HF
is Fair-Rite #31. See the very specific designs on my website,
k9yc.com/publish.htm for transmitting chokes, and use them for chokes
to protect equipment. Chokes should be on every cable connected to the
gateway and the router.
I have had the Asus main mesh unit as the roiuter with the fiber gateway in
bridge mode but have tried setting the Mesh system into access point mode and
using the Ubee as the router, same results.
I do have a Balun Design 1115d 1:1 isolation choke I could put in the coax line
either where it transitions to 450 Ohm ladder line or at the antenna switch but
my feeling is this may be brute force RF getting into the Ubee gateway.
That's the least effective spot to kill common mode current. Further,
with the extreme mismatch in your antenna system, any product that did
anything useful would be frying. I don't consider any of these products
to be doing anything useful.
While you're on my website, download and study my tutorial on Grounding
and Bonding. And buy a copy of the N0AX ARRL book on the topic, to which
I contributed extensively. Make sure that you get the Second Edition,
which added material on what to do about grounding and bonding antennas
for electrical safety, and which also makes problems like yours less
likely.
The earth is not a sump into which RF problems are poured. It's ONLY
functions in a station are 1) Lightning protection; and 2) an essential
part of some directional receiving receiving antennas. The earth is big
resistor. A connection to it does not make our stations work better.
Finally, I suggest that you try to figure out how to rig one or more
antennas that are close to resonant on the bands where you want to use
them, feed them with coax, and put serious chokes at the feedpoint(s).
If you have room for a G5RV (which is really a 20M antenna), you have
room for an 80/40 fan dipole, which also resonates on 15, and is easy to
build. And it's pretty easy to find a way to work a 20/15/10 fan. Both
antennas are better performers than that G5RV.
73, Jim K9YC
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