One RDF not mentioned, that was my favorite on board, is the Lokata 7
hand held with a very good built in compass. LF (marine/aero) and BCB
only with digital frequency readout.
https://www.ebay.com/itm/Lokata-7-Vintage-Marine-Radio-Direction-Finder-RDF-Hand-Bearing-Sestrel-Compass-/224210468351
Grant KZ1W
On 1/27/2021 20:47, AA5CT via RFI wrote:
Do not under-sell the usefulness the cardioid (unidirectional) antenna pattern
adds (via the "Sense" antenna function) when DFing noise or other signals
when using a Coastal Navigator/NAV 101 receiver.
Riding a bicycle and continually 'rotating' the cardioid antenna I can
practically
'drive up to' any interfering signal on the 160 or 80 meter bands when DFing
same.Using a loopstick alone (with only nulls to go by) is a little trickier.
Nowadays I feel quite confident when taking compass bearing readings
for later plotting when using the Coastal Navigator/NAV 101 DF receivers,
first confirming the direction of the source using Sense and then refining
with a null (if sufficient signal strength allows). ALSO NOTE the ferrite
rod antennas in these units employ internal shields to eliminate E-field
response and/or interactions with the operator's hands when in proximity
with the rotatable ferrite bar antenna..
About the Pilot - The Pilot lacks the Sense antenna feature that the Coastal
Navigator/NAV 101 DF receivers have. I have a couple of these too,
but be CAREFUL when putting the batteries into the holder. There are
markings for Mercury batteries which in the day had little 'posts' on the
opposite of what we expect today (polarity is reversed) and the marking
on the batt holder can be confusing. Incorrect insertion of the batts can
kill the receiver.
Also, I have found that the Coastal Navigator is the ONLY Marine DF
receiver that has a functioning Sense antenna feature. The Benmar/Bendix
series model 555 Sense function does not operate, and neither does the
Sense function on the one model (6140) Ray Jefferson I have. A couple
of us here locally have owned the Bendix/Benmar model 555's and the
Sense feature did not work on any of them.
Additionally, the so-called "BFO" on the NAV 101/Coastal Navigator
modulates the final IF amplifier with a 400 Hz tone so a CARRIER ends
up with a tone on it; this does NOT aid on SSB reception.
de AA5CT/Jim
On Wednesday, January 27, 2021, 8:12:13 PM GMT-6, Dennis Monticelli
<dennis.monticelli@gmail.com> wrote:
Scott,
Yes, the Pilot series is good and easy to lug around too. Like the others,
they are inexpensive. I have one awaiting restoration.
Dennis AE6C
On Wed, Jan 27, 2021 at 5:56 PM nm8rmedic <nm8rmedic@rocketmail.com> wrote:
Another good portable RDF is the Pilot Pal series, with its long
rotateable ferrite rod antenna and S-meter. Same NDB/MW/Marine Band
coverage. The model I have, Pilot II, also has a DF level potentiometer.
Scott.
Sent via the Samsung Galaxy S8+, an AT&T 5G Evolution capable smartphone
-------- Original message --------
From: Dennis Monticelli <dennis.monticelli@gmail.com>
Date: 1/27/21 18:18 (GMT-05:00)
To: rfi@contesting.com
Subject: [RFI] tracking RFI with a marine direction finder
All,
Another useful and inexpensive tracking tool is a vintage marine direction
finder. My particular model (Newmar NAV 101, but sold under many a private
label) is battery powered and has three bands: Beacon, BCB, and Marine (1.6
to 4MHz). It has an RF gain control, sig strength meter, a BFO of sorts,
and of course a big lovely azimuth calibrated rod antenna that is capable
of nice nulls. I found mine on the local CraigsList but there is always
eBay. Many different makes and models were made.
Dennis AE6C
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