This won help with the problem, but I have to relate a story.
While residing in a large apartment complex in on the east side of
Loveland, Colorado, for two years out of the High Park Fire where we lost
everything, I couldn't help trying to load up the downspout on 75-meters.
We were on the top floor, so I thought a top-fed (inverted) vertical might
work OK in spite of all the RFI from everywhere throughout the complex. I
managed to obtain an acceptable match at 10-watts, so I raised the power to
50-watts. WRONG. That set off the fire alarms throughout the complex
which was about 1.5 city blocks large! I didn't repeat the feat, but I'll
confess with all the babys crying and wailing and horns in the parking lot
going off in the middle of the night, I was sorely tempted.
Couldn't even have anything (antenna) attached to the mini-patio railing
without management coming down on me. I used what was available - the
downspout. I made a few contacts on 40-meter, but never again tried 75.
Dave - WØLEV
On Sat, Jul 28, 2018 at 3:14 AM, Dave Cole (NK7Z) <dave@nk7z.net> wrote:
> Stan,
>
> Add a decent. (as high an impedance as you can build), choke at the
> feedpoint of the antenna right after any impedance matching device, then
> add another at the point where the coax enters your home.
>
> If you are still having issues, see if your alarm systems are tied
> together to a central unit, you might want to look at that as well.
>
> Take a look at Jim's, (K9YC), papers on suppression using chokes. See:
>
> http://k9yc.com/publish.htm
>
> under "Hum, buzz, and RF Interference"...
>
> 73s and thanks,
> Dave (NK7Z/NNR0DC)
> https://www.nk7z.net
> ARRL Technical Specialist
>
> On 07/27/2018 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.
>>
>> 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.
>>
>> I just bought a DX Engineering Feedline Current Choke (DXE-FCC050H05-B)
>> that is supposed to suppress RFI on antenna leads. That is ineffective.
>>
>> 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.
>>
>> Are there other solutions?
>>
>> Are there brands of smoke detectors that are less susceptible to RFI than
>> others.
>>
>> Any other thoughts?
>>
>> Stan
>> ___________________
>> Stan Zawrotny, K4SBZ
>> K4SBZ.Stan@Gmail.com
>>
>> Real radio bounces off the sky.
>> _______________________________________________
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>> RFI@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>>
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>
--
*Dave - WØLEV*
*Just Let Darwin Work*
*Just Think*
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