[RFI] Invisible Fence ICT-801 interference

Fri Apr 1 10:53:14 EDT 2016

Finally got support from the local installer this week. He installed the 10VK6 filter between the plug in lightning arrester and the twisted pair going underground. All noise coming from the buried electric fence has disappeared.  I checked all bands from the AM broadcast band and up. My 3-el vertical receive antenna which is only about 10’ or so from the buried wire is now quiet.

I wanted the installer to do this so that the neighbor had no doubts about the installation. 

A special thanks to Don for helping with this.

Now I can focus on a dusk-to-dawn fixture that nails me on 1818, 1825 and 1828. Weird that it is these three frequencies where it peaks. Got the direction it peaks, so now do some snooping near darkness.

73,

N2TK, Tony

From: Don Kirk [mailto:wd8dsb at gmail.com] 
Sent: Tuesday, February 09, 2016 5:38 PM
To: N2TK, Tony <tony.kaz at verizon.net>
Cc: RFI <rfi at contesting.com>
Subject: Re: [RFI] Invisible Fence ICT-801 interference

Below is an E-mail I just sent Tony (N2TK), and thought the information should be shared with the entire group.

------------------------------------------------
Hi Tony,

I talked with the Duane who is in the engineering group at Radio Systems Corporation, and had a very good conversation with him.  Sounds like he had gotten the spectrum plot from you that I sent you, and this confused him because the frequency did not match up with the model you said you were working with.  He said the Pet Safe brand operates at 10.7 khz as well as 7 khz (switchable).  He said the Pet Safe brand has more of a sinewave output whereas my Innotek model has a square wave output which produces much more harmonics.

Nevertheless he said for folks having interference problems they recommend the installation of a Corcom filter model 10VK6.  Just connect this up between the output of the transmitter and the underground wire loop that connects to it.  Sounds like this will function similar to my home brew filter.  I will buy one myself and see how it compares to my filter.

Based on this information you can probably use any number of RFI/EMI suppression filters available from Corcom, Delta Electronics, etc.  I have a couple of Delta Electronics models that I will test out as time permits.

I will also make a posting to your original post with this info.

Don (wd8dsb)
--------------------------------------------------------------------

PS.  The Innotek brand which I have transmits at around 8.17 khz.

73,

Don (wd8dsb)

On Fri, Jan 29, 2016 at 6:32 AM, N2TK, Tony <tony.kaz at verizon.net <mailto:tony.kaz at verizon.net> > wrote:

Don,

Great info. I will give them a call today. And if I run into a roadblock I will contact you about the filter.

73,

N2TK, Tony

From: Don Kirk [mailto:wd8dsb at gmail.com <mailto:wd8dsb at gmail.com> ] 
Sent: Thursday, January 28, 2016 3:50 PM
To: N2TK, Tony <tony.kaz at verizon.net <mailto:tony.kaz at verizon.net> >
Cc: RFI <rfi at contesting.com <mailto:rfi at contesting.com> >
Subject: Re: [RFI] Invisible Fence ICT-801 interference

Hi Tony,

I have a lot of experience with invisible fence transmitters, and I even reverse engineered (decoded the 8 bit code my transmitter sends) and then designed and built my own in case my purchased one ever dies.  For my purchased transmitter I had to make my own low pass filter using some radio shack snap on RF choke Frames (part number 273-0104), and would be glad to sketch up my filter if you can't resolve the problem another way.  I installed my invisible fence transmitter loop antenna wire above ground along the top of my vinyl coated chain link fence, and it is not far from my 160 meter TX vertical or my 3 small receive pennants (30 feet or less).  The problem I had was that my dog was jumping over my fence, so I installed the transmitter loop wire at the very top of my fence and turned the power way down so my dog would only gets a correction if its collar gets within a foot of the top of the fence (this fixed my problem while still allowing my dog full use of the yard).  Having the loop above ground is a worst case condition, so very pleased that I was able to rid myself of the interference using the above mentioned choke.  One of my next door neighbors has the identical transmitter I have but it is underground and about 10 feet from my property line and I have no problem with his system.  Also another next door neighbor has a different brand transmitter (probably similar to your neighbors), and I don't have any problem from his system.  

It looks like the transmitter you are talking about is made by a company called Radio Systems Corporation, and they are a big player.  The unit you have is part of their Pet Safe brand.  They also have another brand called Innotek (which is the brand I have experience with).

Some models have a transmitter output power level control, but other models have a fixed output level.

I suggest you call Pet Safe and discuss the problem with them on the phone and see what kind of help they can provide (their on line technical support line is very friendly).  Their phone number is 1-866-738-4379 <tel:1-866-738-4379> .  It sure would be nice if they sold a filter, but this is something I have never discussed with them.  If you hit a dead end let me know and I will sketch up my filter design for you.

73,

Don (wd8dsb)

On Thu, Jan 28, 2016 at 2:28 PM, N2TK, Tony <tony.kaz at verizon.net <mailto:tony.kaz at verizon.net> > wrote:

Next door neighbor installed an ICT-801 Invisible Dog Fence.

It is supposed to run at 7KHZ. But it is sure strong on 160M and to a lesser
degree on 80M. The buried wire is about 10' from my inline verticals for
receiving. But I can also hear it somewhat in a Pennant that is about 30'
away. I can hear it as hash (but not loud) up to 15M when pointed in that
direction.

Does anyone know if this is normal for these units to put out so much noise?
Does ferrite on the wires from the unit to the buried wires and the battery
backup unit help at all? Before I ask the neighbor if it is okay to try some
ferrite snap on cores I wanted to ask here if anyone has had success
cleaning up this thing.

73,

N2TK, Tony

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