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Re: [RFI] ROTHR Interference?

To: "Rfi@contesting.com" <rfi@contesting.com>
Subject: Re: [RFI] ROTHR Interference?
From: "Paul Christensen" <w9ac@arrl.net>
Date: Tue, 30 Sep 2014 15:10:15 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Don,

Many thanks for confirming. I'm a bit surprised it's heard as far north as VE6. Here in FL, it's pretty damn bad. Later this week, I'll place a call into Raytheon's ROTHR division. They probably won’t offer up much information but it's a try.

Paul, W9AC

-----Original Message----- From: Don Moman VE6JY
Sent: Tuesday, September 30, 2014 3:02 PM
To: Rfi@contesting.com
Subject: Re: [RFI] ROTHR Interference?

I hear it on 80m, often covers from  ~3.3 to 3.750 in one chunk before it
moves on...  Noticed it last winter/spring but it seems to be more regular
now and a bit stronger.

I must comment on your QRZ page - very nicely done.  That's what a QRZ page
should be .....

73 Don
VE6JY

On Tue, Sep 30, 2014 at 11:50 AM, Paul Christensen <w9ac@arrl.net> wrote:

For the past month, I've been plagued with a "chopping" interference
between 80m-30m. The interference is not local, it's ionospheric. This is
not a form of interference you find by getting out and searching the
neighborhood.

Ops from Florida are hearing this and I hear it being discussed on the
80m/40m nets. it started about three months ago. It has the same level as
the Department of Homeland Security's ROTHR system that detects illicit
controlled-substance traffic in the Caribbean by triangulating pings from
three high-power ROTHR systems located in Texas, VA, and PR.  I have not
heard the usual ROTHR sweeps during this time.  This new form of sweep may
have taken the place of the older ping that sweeps at a rate of 100
kHz/sec. That sweep sounded like someone transmitting a carrier and
spinning the VFO knob at a constant rate.  The new sweep has a fast
chopping component as well as fast pulses within each sweep.  This lasts
for a bit over 2 minutes and repeats at different parts of the spectrum
between 3-10 MHz. If any of you recall the "Russian Woodpecker," it sound
much like that system only with faster pulses.

Like the DHS ROTHR, it's us folk in Florida that get the brunt of it.  If
you operate outside of the southeast U.S., you may not even hear it.

https://www.txarmymars.org/downloads/RaytheonRadarOverTheHorizon.pdf

I have attached a photo of the sweep at the opening of my QRZ.com page.

http://www.qrz.com/db/W9AC

Anyone know for sure if DHS changed the sweep pattern?

Paul, W9AC


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