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Tuning
Tuning the
COM-40VA
40 Meter Vertical Antenna is straightforward and intuitive. If you use an
SWR meter or an analyzer at the base of the antenna you will get the most accurate readings in a
timely fashion.
Since the 2:1 SWR bandwidth of the antenna is wide the adjustment parameters are relatively broad
and fine adjustment is not usually necessary.
Note: For the purposes of these instructions the term “resonance” or “resonant frequency” is
defined as the point of lowest SWR and may be used interchangeably.
To adjust the low SWR point in the 40 meter band, merely adjust the length of the top tubing
section in the normal manner, i.e., making it longer lowers the 40 meter resonant frequency and
shortening it raises the frequency. The top element section is made moveable by loosening the
element clamp and then sliding the upper element section of the antenna either closer to the base of
the antenna or farther away depending on whether you want to lower or raise the frequency of
resonance. Be sure to tighten the clamp after making an antenna length adjustment.
Frequency MHz
Approximate Overall Length
7.000
34 Feet 5 inches
7.125
32 Feet 10 inches
7.175
32 Feet 7 inches
7.300
33 Feet 3 inches
The approximate lengths shown in this table should also be used when making resonant radials for
an elevated mount antenna (feedpoint is 3 feet or higher from ground level). For ground mounted
antennas, resonant radials are not required.
Thank you again for purchasing a Comtek Systems
COM-40VA
40 Meter Vertical Antenna. .
Enjoy your 40 Meter performance while contesting and DXing.
73
,
Comtek Systems
www.comteksystems.com
