Page 10
Antenna Operation
The Alpha Loop antenna has a built in tuning knob, which is black, on the Alpha Match. It is with
this knob that you tune the antenna to the lowest SWR of less than 1.9:1 on any frequency
from the 10 Meter through the 40 Meter band. The following technique has proven to be the
easiest method for tuning the Alpha Loop in nearly all scenarios:
1)
After attaching your coax, turn your radio on and to the frequency you would like to
operate, then adjust the volume so you can hear it while standing at the antenna.
2)
Turn the black knob on the Alpha Match till you hear the loudest noise level coming
from the speaker. You may now select either or both steps 3 & 4 in your tuning of the
antenna. We recommend using both when you first start using the antenna.
3)
Set the meter on your transmitter to show SWR upon transmit. You may also use an
external SWR Meter/Analyzer. If using an analyzer, simply tune for the lowest SWR using
the black knob on the Alpha Match. Otherwise, return to the radio by barely turning the
black knob on the Alpha Match, and then set your rig into transmit mode at the lowest
power output available. While watching the SWR meter, tune for the lowest SWR.
Hint – It is easier to learn how to tune the Alpha Loop on 40 meters.
OPTIONAL REVERSE TUNING (How to account for hand capacitance while tuning)
a.
To compensate the effect of hand capacitance that might occur, a technique
called reverse tuning can be used. To reverse tune a magnetic loop, tune for
minimum SWR while touching the Black Knob on the Alpha Match, say 1.9:1; and
then when you remove your hand you might see 4.3:1 for example; then all you
have to do is tune for 4.3:1 while your hand is on the knob to achieve an SWR of
1.9:1 when you remove your hand.
NOTE – High voltages are present when transmitting, no matter how much or little power is
applied. Do not touch any part of the Alpha Loop except the black knob while transmitting.
