[RFI] RF

[Robert Nobis]

Jim,

In may case, I had an outdoor antenna, however the feed line was fairly close the electronically activated doggy door. Using your common mod choke on the feed line near the connection to the antenna resolved my issue.

Merry Christmas.

73,


Bob Nobis 
n7rjn at nobis.net


> On Dec 23, 2016, at 15:33, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
> Bill and Bob,
> 
> While this is certainly worth trying, I suspect that the problem is caused by the antenna itself being so close to the victim devices. And I would definitely wind serious chokes onto wiring connected to that garage door unit. By serious, I mean at least 12 turns around a #31 toroid, or half as many through a clamp-on that's an inch long.
> 
> Since this antenna is inside, I suspect that you're running barefoot. If so, or if you're running less than about 300W, the bifilar-wound choke using a pair of #12 or #14 THHN on a single #31 core would handle the power unless the antenna is VERY badly unbalanced.
> 
> BTW -- about six months ago, I updated RFI-Ham.pdf to address power handling of bifilar wound chokes on #31 toroids. If you are considering using one, by all means download it again.
> 
> 73, Jim K9YC
> 
> 73, Jim K9YC
> 
> On Fri,12/23/2016 1:41 PM, Robert Nobis wrote:
>> Bill,
>> 
>> I had a similar problem with an electronically operated doggy door.  What I found was that I had relatively high common mode current on my antenna feed so the feed was also radiating. My antenna was not perfectly balanced as one end was close to metal siding. I added an antenna feed line choke following the recommendations from Jim Brown’s tutorial (k9yc.com/RFI-Ham.pdf <http://k9yc.com/RFI-Ham.pdf> ), and the doggy door problem disappeared.  I used 6 turns of RG8 through five 2.4” o.d. #31 toroidal cores for 80-meters.
>> 
>> 73,
>> 
>> Bob Nobis
>> n7rjn at nobis.net
>> 
>> 
>>> On Dec 23, 2016, at 10:59, Bill Price <billp7634 at sbcglobal.net> wrote:
>>> 
>>> 
>>> I live in a HOA subdivision with restrictive covenants. As such, at this time all my antennas are in my attic. I just strung a fan dipole up for 75 and 17. When I operate on 75 I have RF issues. Two of my security lights come on, one of the garage door opener lights come and an electric soap dispenser (motion activated) comes on and dispenses a butt load of soap. I thought it may be due to one side of the 75M dipole coming close to a length of romex. So I located that romex and put two snap on ferrites around that wire with the romex wrapping twice through the ferrite. I also put a ferrite on the power wire from the wall wart after having wrapped that several times. The problem still exists. I also have a 40M dipole and a 10M beam in the attic and have no problems with running a KW at any frequency other than 75M. The ferrites I have are a 31 mix. Any ideas as to how to solve this issue?
>>> 
>>> Bill   W5LO
>>> _______________________________________________
>>> RFI mailing list
>>> RFI at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
>> _______________________________________________
>> RFI mailing list
>> RFI at contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
> 
> 
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi