The old portable marine RDF radios with a ferrite rod antenna would work
well. Besides tuning the marine LF beacons many also covered BC and
low MF bands. I tossed mine long ago, maybe there are some lurking in
attics or garages, they provided a very sharp null for DFing.
There are many on ebay, search "radio direction finder"
Grant KZ1W
On 12/9/2014 4:45 PM, Rick Stealey wrote:
In order to identify the location of the transmitter by radio methods (as
opposed to Doug's contacts identifying the culprit) it is eventually going to
require some more accurate antenna patterns than you get from Beverages and
other rather broad pattern antennas.
If you will remember three years ago we had a spur on 1818 and began the same way, with lots of
signal reports of strength (of limited value due to all the variables), some "Beverage
reports" such as "It's stronger on my NE Bev than my east Bev." But it was Don,
WD8DSB in indiana, with three flag type antennas who took careful measurements and eventually
identified the general area as being south Jersey.
What enabled us to drive right up to the door (figuratively) of the spur
generator back then was only THREE readings, taken by me, with a portable loop
antenna. Don plotted the vectors, and since I was essentially driving in a
circle around the source he was able to triangulate the source right to a city
block. It may not be that easy this time because the area hasn't been narrowed
down small enough yet. The advantage of a loop is not that it points toward
the signal, but that it points AWAY from the signal, at 90 degrees, and is very
sharp. This is nothing new whatsoever. In fact it is amazingly simple. I
built the loop that found that spur in only a total of four hours. All it
takes is some pvc pipe, and joints, and glue them together and wrap 4 turns of
wire and a coupling loop for. 50 ohm coax. The hardest part, naturally, is to
find an interested person who will take such an antenna for a one day ride, say
around New Brunswick and get some bearings. Initially
,
since we are not sure of the area, it may require a trip of several hundred
km (as they say in Canada). I would be very tempted to take a trip, but have
been lax in renewing my passport and they won't let me cross the border anymore
without one. Damn !
Rick K2XT
From: jkaufmann@alum.mit.edu
To: topband@contesting.com
Date: Tue, 9 Dec 2014 19:22:27 -050!
Subject: Re: Topband: That 1.9 MHz radar signal...
Stay tuned, and any additional reports are welcome...I think we have
narrowed it down to something in the Maine/New Brunswick.Nova Scotia areas.
73,
Doug K1DG
I would also put Newfoundland in the region of interest. From my location
in the greater Boston area, the direction of arrival is more east than
northeast (around 75 deg as I said earlier). I get the same heading every
time I measure the signal and I'm confident in my ability to resolve
directions with my RX array. The F/B I see on this signal with my array
suggests the signal is not particularly high angle. The area around St.
John's, Newfoundland area would be right in line with my estimated direction
of arrival.
73, John W1FV
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