Jim,
Thanks for your response.
At a minimum, ALL of that wiring should be twisted pair, and ALL of that
wiring should have a GOOD common mode choke at each end. By "good" I mean
follow the guidelines in k9yc.com/RFI-Ham.pdf CAT5/6 cables consist of
four excellent twisted pairs.
I am meeting with an electrician on Wednesday to discuss some wiring that I
need done in my shack and I am going to have him take a look at the system.
I have a copy of your guidelines that I will give him.
BTW, I have been following this forum for over two years. If I may make an
observation: It might be more helpful if, instead of telling people to
"study the guidelines in k9yc.com/RFI-Ham.pdf", you were to paraphrase the
information from it that is relevant to the current problem. The paper is
71 pages long and a bit much for someone looking for a specific solution.
Also, it is a fine treatise of the subject, but it is a little above the
heads of most laymen. You provide fine information on the forum, but we
need precise, practical solutions.
Please excuse me if I seem ungrateful for your response. I was especially
looking forward to seeing what you would have to say, hoping that you would
respond. Thank you again.
Stan
___________________
Stan Zawrotny, K4SBZ
K4SBZ.Stan@Gmail.com
Real radio bounces off the sky.
On Fri, Jul 27, 2018 at 2:33 PM, Jim Brown <jim@audiosystemsgroup.com>
wrote:
> On 7/27/2018 10:49 AM, Stan Zawrotny wrote:
>
>> I have been troubled for quite some time with our smoke detectors
>> frequently beeping (two beeps) when I am working HF. It is worst on 80 and
>> 40, but also occurs frequently when I am on 15 and 20 meters. The beeping
>> will be intermittent at intervals of 1-3 minutes and will last for a
>> couple
>> of minutes after I am through transmitting.
>>
>
> Describe these units -- are they "free-standing," with no connected wires,
> or are they wired to a central unit?
>
> I has happened with several rigs. Yaesu FTdx5000, Flex-6600M and Icom
>> IC-7300, at power ranging normally from 50-100 watts.
>>
>> Of course, the antenna system is likely the culprit. It consists of
>> several
>> OCF dipoles: one 160-10 M and two 80-10 M. (I know OCF dipoles are bad for
>> RFI). All have 1:1 baluns at the antenna and at the shack.
>>
>> I have tried clip-on ferrite beads on the power leads of the smoke
>> detectors without luck.
>>
>
> Of course they don't work. Study k9yc.com/RFI-Ham.pdf
>
> I just bought a DX Engineering Feedline Current Choke (DXE-FCC050H05-B)
>> that is supposed to suppress RFI on antenna leads. That is ineffective.
>>
>
> Where is it installed? To be effective it MUST be at the feedpoint (that
> is, where the feedline connect to the horizontal part of the antenna.
>
> I am now considering replacing the entire smoke detector system. We share a
>> house with my daughter and there are 9 units tied together in the system,
>> so the cost will not be small.
>>
> AH! Now we see the problem -- all that interconnect wiring is a receive
> antenna, picking up your transmitted RF FROM THE ANTENNA and getting
> detected in those units. In general, alarm and security systems of all
> types are notorious for poor design and construction that CAUSES RFI to
> their system. Likewise, the power line (via the power supplies to the
> unit). At a minimum, ALL of that wiring should be twisted pair, and ALL of
> that wiring should have a GOOD common mode choke at each end. By "good" I
> mean follow the guidelines in k9yc.com/RFI-Ham.pdf CAT5/6 cables consist
> of four excellent twisted pairs.
>
> Are there other solutions?
>>
>> Are there brands of smoke detectors that are less susceptible to RFI than
>> others.
>>
>
> I can't help with that.
>
> 73, Jim K9YC
>
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