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Re: [RFI] 40M QRM/RFI

To: Randall K Martin <rkmassoc@comcast.net>, Leonard Halvorsen <lhalvors@pppl.gov>, rfi@contesting.com
Subject: Re: [RFI] 40M QRM/RFI
From: Gedas <w8bya@mchsi.com>
Date: Fri, 12 Jan 2018 17:36:11 -0500
List-post: <mailto:rfi@contesting.com>
Yes most if not all will have a main PCB controller board with a uP or at least a u-controller and all kinds of discrete and integrated drivers and relays inside the main control panel box.

That unit is normally hidden downstairs and is central to the entire security system.  It is powered via a 117 VAC wall wart, etc which you will need to unplug.  Then inside the control panel (box) there will usually be a 12 VDC gel-cell for emergency backup. You will need to unplug the positive lead from that battery to totally deactivate the alarm system. If connected to a traditional twisted pair telephone system disconnect that as well.  Just make sure the owner notifies any monitoring company of what is going to be happening before you do any of this. You also should double check to see if by doing this you will wipe any stored settings of the alarm system.....owner would be real ticked off if the entire house had to be re-programmed. And also take a look at any remote control panels to see if they have any kind of hold up batteries etc inside. These are the small panels in the hallway or kitchen where you enter your code in to arm or disarm the system as you come and go.

Gedas, W8BYA

Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

On 1/12/2018 4:44 PM, Randall K Martin wrote:
I am fairly certain that one of the houses has a security system installed. Do these generally have some kind of main control unit that I could have him unplug as an easy test, or is it more involved than that. I'll find out if that is the source, before asking what can be done do cut down on the RFI.

Thanks Jim K9YC for your comments, too.

Randy

On 1/12/2018 2:36 PM, Leonard Halvorsen wrote:
Are those 4 houses high-rent-district kind of places?
Sounds like maybe a memory or sensor refresh on a security or fire detector system.


On Fri, Jan 12, 2018 at 3:24 PM, Randall K Martin <rkmassoc@comcast.net <mailto:rkmassoc@comcast.net>> wrote:

    I have recently noticed a 24-hour per day source of QRM on 40M CW.
    On 7031.9 there is a steady stream of dashes, with the dash lasting
    about 1.5 seconds and then a space of 0.5 seconds. What is
    interesting is that there is a second signal which is much weaker on
    7041.9 which is the exact inverse of the first. When the first
    signal is on, the second is off, and vice versa. Both sources peak
    at the same heading, roughly 90 degrees from my main 40M yagi.

    I have zeroed in on a spot about 2000 feet east of me where the main
    signal is almost 40 dB over on a mobile rig (K-3 with hamstick).
    I've ordered a DF loop antenna so I can try and pin it down further
    before knocking on doors. There are four houses in the immediate
    vicinity.

    Just wondering if anybody in this group has ever come across
    something like this. Google searches and archive search for this
    reflector came up empty. The signals do not drift in frequency.
    Speculation as to the source?

    73 Randy K0EU
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