[RFI] Not your typical invisible fence RFI

[Don Kirk]

Hi Tony,

Glad to hear the 10VK6 did the trick for you and I thought that was the
case.  I actually have a 10VK6 sitting here specifically for this
application that I can provide the Invisible Fence installer but I want
them to provide an answer to the problem versus me force feeding them.  If
they suggest a 10VK6 then I will pull it out and give it to them.  If they
look clueless then I will tell them about the 10VK6 and tell them it was
the recommended filter by the engineering department at Radio Systems
Corporation which manufactures the Invisible Fence as well as Innotek and
other branded in ground pet fence systems, and that they should follow up
with them about the recommendation.

Thanks, and 73.
Don wd8dsb

On Sun, Jan 23, 2022 at 1:24 PM <tony.kaz at verizon.net> wrote:

> And thanks again Don for the help. I felt more comfortable with an off the
> shelf solution and have it installed by the original installer.
> Easy fix with great results.
> N2TK, Tony
>
>
> -----Original Message-----
> From: Don Kirk <wd8dsb at gmail.com>
> To: N2TK, Tony <tony.kaz at verizon.net>
> Cc: joek1vw at gmail.com <joek1vw at gmail.com>; rfi at contesting.com <
> rfi at contesting.com>
> Sent: Sun, Jan 23, 2022 1:05 pm
> Subject: Re: [RFI] Not your typical invisible fence RFI
>
> Hi Tony,
>
> Yes, I remember your case.  I'm the one that told you about the 10VK6 back
> in 2016 per a recommendation I had received from the Innotek engineering
> department.
>
> 73,
> Don (wd8dsb)
>
> On Sun, Jan 23, 2022 at 12:56 PM <tony.kaz at verizon.net> wrote:
>
> Had a problem  with the next door neighbor's inground dog fence. Wiped me
> out on 160M with a receive antenna within 10' of the buried wire. Provided
> a Corcom 10VK6 filter to the installer of the dog fence. It was put between
> the output of the transmitter and the underground wire. It got rid of the
> interference for 6 years now.
> N2TK, Tony
>
>
> -----Original Message-----
> From: Joseph Bouchard <joek1vw at gmail.com>
> To: Don Kirk <wd8dsb at gmail.com>
> Cc: RFI <rfi at contesting.com>
> Sent: Sun, Jan 23, 2022 11:41 am
> Subject: Re: [RFI] Not your typical invisible fence RFI
>
> Don,
>
> Our invisible fence is the typical 10khz variety, but I found a 3 layer
> approach worked well... each did a bit of reduction, and together it was
> enough.  Maybe that multi layer approach can help you.
> - an FT240-31 on the wallwart cable... on the DC portion going to
> transmitter.  This reduces harmonics backfeeding into the house wiring.  In
> this case ferrites on the AC side didn’t make much difference, YMMV.
> - i put a ferrite on each leg of the fence wire near the transmitter.  I
> used 1/2” snap-on group 31 with as many wraps as I could fit.  This reduces
> harmonics on the fence wire.
> - we were able to turn down the gain knob on the fence transmitter quite a
> bit and it will still trigger the collar. Less transmitter power = less RFI.
>
> Hope that helps,
> Joe K1VW
>
> > On Jan 23, 2022, at 10:23 AM, 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)
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