[RFI] Old invisible fence RFI report

[AA5CT]

I had a report about invisible fences creating 'carriers' on 160
(and also 80) meters some years back - here is a post about
that back when (2016):

http://lists.contesting.com/archives//html/RFI/2016-10/msg00010.html

As a matter of fact, I had located three distinct sources back then, after
it was all done. Designs must have changed in the interim b/c those
were the only noticeable CW-like carriers I saw on 80 or 160.

de Jim AA5CT

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    On Sunday, January 23, 2022, 4:49:58 PM GMT-6, Hare, Ed, W1RFI <w1rfi at arrl.org> wrote:  
 
 I found the certification record easily.


https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=rQqvlnXl0jI%2BsFf%2Fvos1Hw%3D%3D&fcc_id=KE3-3002587
FCC - OET TCB Form 731 Grant of Equipment Authorization<https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=rQqvlnXl0jI%2BsFf%2Fvos1Hw%3D%3D&fcc_id=KE3-3002587>
OET TCB Form 731 Grant
apps.fcc.gov
It is not a Class B device; it is an intentional emitter.  The rules for emissions from intentional emitters, when coupled with a flawed extrapolation method that the FCC defines is rather high by radiocommunications standards.  The harmonic suppression required in the rules is essentially 0 dB, with spurious emissions limited to the same levels as would be intentional emissions on the same frequency.

Fortunately, the cure worked.  Interestingly, ARRL has received very few complaints about these, although by the look of the rules and the certification test report, it looks like interference is likely.

Ed


________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of David Eckhardt <davearea51a at gmail.com>
Sent: Sunday, January 23, 2022 1:06 PM
To: Don Kirk <wd8dsb at gmail.com>
Cc: RFI <rfi at contesting.com>
Subject: Re: [RFI] Not your typical invisible fence RFI

There is no record on the FCC OET site for KE3-3002587 which is shown on
the image of the label as the FCC ID number for the wireless transmitter -
Part 15, Class B, Subpart B, intentional radiators.  However, if I input
only the Grantee Code of KE3, indeed, all kings of pet care products are
shown.  This might be a knockoff with a bogus FCC ID????  Also, as a Class
B product - home and small office - the FCC logo is required on the
regulatory label.  It is absent.

Dave - WØLEV

On Sun, Jan 23, 2022 at 3:23 PM Don Kirk <wd8dsb at gmail.com> wrote:

> I just uploaded a video onto YouTube that documents wideband RFI on 20
> meters that I tracked down to my neighbors invisible fence transmitter, and
> it's not the typical approximate 7 or 10 KHz interval RFI encountered with
> inground invisible fences.  The RFI which is at least 150 KHz wide at my
> house moves around based on outdoor temperature and on warmer winter days
> it drops down to slightly below the 20 meter band.
>
> I was hoping the problem was with the wall-wart power supply feeding the
> transmitter but it was not.  The transmitter has battery backup and the RFI
> is still present with the wall wart unplugged, and we also tried a linear
> lab grade power supply in place of the 19.0 Vdc 1 amp wall wart with no
> noticeable difference in the level of RFI at my house.
>
> Unfortunately the transmitter is not part of a DIY system so the
> manufacturer (Radio Systems Corporation) requires that we deal with the
> local "Invisible Fence" Dealer which is our next step.
>
> An interesting note is that when I first tracked the RFI down to my
> neighbors home I wound up near the main circuit breaker box.  We then tried
> sniffing the circuit breakers with a very small loop to see what circuit in
> the house the RFI was originating (assuming the RFI was being conducted on
> house wiring) and this technique typically works great.  We did not detect
> the RFI on 20 meters on any of the circuit breakers which was interesting
> because the RFI was strong near the main circuit breaker box.  It turned
> out that the invisible fence transmitter is just a few feet away from the
> main circuit breaker box which explained why the signal was strong near the
> main circuit breaker box.
>
> For those interesting here is a link to the video documenting the RFI:
> https://youtu.be/rHABjR0GZWg
>
> P.S. I have great neighbors that are wonderful to work with on RFI issues.
>
> 73,
> Don (wd8dsb)
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>


--
*Dave - WØLEV*
*Just Let Darwin Work*
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