Array Solutions - SAL12/20/30 - Mark II Manual – Rev. 1.5.1 – September, 2018
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Optimizing the F/B
To maximize the F/B start the following procedure. Set up a transceiver on a test table
40-50 feet away from the loop and bring the feedline to the radio.
1.
Start with the couplers in the suggested positions and listen to an AM or MW
broadcast signal which is steady and off one of the diagonal directions. Note the
F/B by using the “Flip” button to reverse the pattern.
2.
Move all the couplers 6 inches closer to the mast, you may see the F/B increase or
decrease. Note the F/B again,
3.
Now move the couplers in the opposite direction away from the mast by 12
inches. Note the F/B. If it is worse than the other two positions put the couplers
back towards the mast by 12 inches. And move the couplers 3 inches in towards
the mast. Repeat until you find the maximum F/B.
4.
Secure the couplers in this position.
5.
It has been found that the lower frequencies are the most critical. Higher
frequencies will have good F/B once you find the low frequency best F/B spot.
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NOTE:
A reliable signal source like a broadcast station which its position
relative to the SAL antenna is well known can be used to optimize the front to
back of the SAL antenna. Keep in mind that at times near dusk and down the
propagation will change and incoming wave angles will do as well and the front
to back can vary a great amount while this propagation conditions are changing.
OPERATION
There are several buttons that you will easily use in operating your array.
1.
Yellow counter clockwise and clockwise buttons will electrically steer the array,
the LEDs will show the direction you are listening. Eight directions are possible.
2.
FLIP white button will flip the direction 180 degrees to allow easy F/B
measurements.
3.
FLIP Automatic – Holding the FLIP button for 2 seconds will cause the array to
flip back and forth 180 degrees every 2 seconds. Very handy for F/B
measurements over time.
4.
UNIDIRECTIONAL sets the array in single direction mode.
5.
BI-DIRECT button places the array in Bidirectional mode. Handy for listening in
opposite directions. Signals will be much stronger in this mode at lower
frequencies, so it is also useful for weak signal work at low frequencies.
6.
Power – power on/ power off. When off the center LED is always lit. Minimal
current is being drawn (approximately 10 mA).
Important note:
When you first install your Shared Apex Loop™ system, we recommend that you spend
plenty of time listening to gain an understanding about how the antenna works. Good
sources of test signals are WWV at 2.5 (at night), 5 and 10 MHz of course, ham radio
signals in the 40, 80 and 160 meter bands. AM radio stations in the broadcast band are
also good, but remember that local stations may not show as much front-to-back as
distant stations. In the AM broadcast band you should be able to detect two and
