[CQ-Contest] RF tripping UPS

Jim Brown k9yc at audiosystemsgroup.com
Fri May 31 13:28:07 EDT 2019

On 5/31/2019 8:09 AM, Richard Zalewski wrote:
> Thanks for the replies and suggestions.
> The crazy part is nothing in the station physically has changed.

Many of the old hands at this have also advised us to check every piece 
of coax for issues with the shield. Damage to the shield, 
poor/broken/deteriorated contacts at connectors.

> I have a bus bar on the back of the operating desk and everything is
> bonded to it.  (Will check for tightness today).  Then there is a single
> conductor to 2 ground rods.  One of them I have to water (I am in AZ) the
> other is next to a sprinkler so it stays moist.

The earth is not a sump into which RF or noise is poured. What matters 
most is BONDING -- ALL grounds in our homes MUST be bonded together. 
That includes those rods outside the shack, the power entry, CATV, 
telco, etc. The earth is a big resistor. Is that buss bar bonding to all 
of those grounds? It must be. That bonding certainly should include the 

Two references on this. N0AX's recent ARRL book on Grounding and 
Bonding, to which I contributed. Second, these slides for a tutorial 
talk I've done at Visalia, Pacificon, and to several clubs. 
> I have used multiple clamp on ferrite type 43 material where I can not
> wrap the conductor around a larger core.

#43 material is not useful on 80M. #31 is the only Fair-Rite material 
useful on the HF bands. Study http://k9yc.com/2018Cookbook.pdf

> I am going into the power panel today and check the tightness of all the
> ground connections.
> The UPS I am using is not a top of the line but as I said I have used this
> model for years.  When this started acting up I replaced it with a similar
> model.
> I will advise if I find anything but sure appreciate the suggestions.

Finally, what are you using for an antenna on 80/75M?  If it is a 
dipole, there should be a good common mode choke at the feedpoint (that 
is, up in the air). See that Cookbook for specific advice. Is it 
"off-center" fed or non-resonant antenna fed with 2-wire line? Antennas 
like this cannot be choked to keep RF off the feedline.

Is it some form of end-fed wire, vertical or otherwise? If so, what is 
the counterpoise for it? Radials? Something else?  A counterpoise 
provides a path for return current. If we don't provide a good one, 
mother nature will use whatever she finds, including the power system 
wiring in our home. Which lights up our home with RF.

73, Jim K9YC

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