Hi all,
Been working on a Superloop MW antenna which I can manually slew. It's
been a project for the past couple weekends (building/staining the wooden
supports, mainly) and completed it yesterday, the 4th. Its dimensions are
36 X 16' and is constructed so that I can physically move one end of the
antenna to have the array favor NW, S or heading of choice. The antenna
is
fed with 75 ohm RG-6 quad shield bought at the Home Depot for $43 / 500'
and a packet of quad-shield "F connectors.
http://www.homedepot.com/p/Southwire-500-ft-Black-RG6U-
Quad-Shield-Coaxial-Cable-56918445/202316309
Instead of installing a fixed value resistor in one corner, I went one
step further and for the purpose of tuning the null, built a fixture which
holds a 2K, non-inductive variable resistor to take the place of the fixed
resistor network. The variable resistor can be adjusted for the best
null,
removed, then the value read with a DVM which provides a value for a
fixed,
more easily weatherproofed, CARBON FILM resistor network to be inserted in
place of the variable resistor. With the loop "looking" generally west, I
used a C-Crane Skywave, which had been modified by removing the internal
ferrite bar and an external MW antenna input added Tuned the radio to
WCBS 880, about 300 miles up the coast, then connected the Skywave radio
to
the loop feed-point with a cable long enough to reach back to the tuning
resistor end of the loop. Adjusted the variable pot for the best null of
WCBS which is generally off the back of the antenna The adjustments took
place at approximately 3PM; both the station and my location were still
in daylight.
Frankly, I was amazed at the results. By adjusting the resistor, (the
final value was 371 ohms) the loop would nearly completely null WCBS which
gave way to a station with a latin format on the frequency. In winter,
WCBS can be heard here on a 24/7 basis at approximately the "S-9" level.
I detuned everything, grabbed my iPhone, went through the process a second
time and recorded a short video, linked below.
https://youtu.be/ugLKjTuncsw
Next step is to review Mark Durenberger's, "Field Information on the
Double D-Kaz Antenna" which has details on moving the nulling pot inside
along with a couple articles on suppressing common mode pickup. Who
knows,
I have 2 supports; this may turn into a D-KAZ v/s the Superloop. It also
comes apart and is compact enough to go in the back of a pickup for a trip
to False Cape State Park, south of Virginia Beach, VA for some seaside
magic.
Chuck Rippel
Chesapeake, VA
On Thu, Feb 2, 2017 at 2:01 AM, 'Steve Francis' via MWDX <
mwdx@xxxxxxxxxxxxxxxx> wrote:
1290 WNBN Meridian MS
1-31 0059 EST
Good with spots for Tax Time Check Cashing and Ted's Alternator and
Starter, including locations and phone numbers; into old school R&B tune
by
Candi Staton. No ID heard - long live local ads!
Steve Francis
Alcoa, Tennessee
Realistic TRF
Select-a-tenna
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