I am no longer using the DXE active antennas. The active antennas worked fine,
but in a multi multi with all of the RF from multiple bands, the active antennas
were trouble (no way to put bandpass filters ahead of the preamps).
As far as terminations, I have not experimented with putting resistors or other
matching networks at the feedpoints of the Valor antennas, however I do plan to
match them to 75 ohms at some point with simple L networks. I'll also add
ferrite feedline chokes at each antenna feedpoint to make certain that each
feedline is isolated. I expect to see a small enhancement to the pattern of the
array with these changes and also I expect the array gain to increase slightly
because of proper matching.
I tuned each mobile antenna but using my MFJ-259B at the end of the 75 ohm
feedline (RG6) for each antenna for minimum VSWR (about 2.2:1) at 1830 KHz.
There is no interaction between these antennas (electrically loaded and spaced
on a square of 98 feet), so they do not couple to each other upsetting the
minimum VSWR readings.
I am very pleased with the results. I'll be installing similar mobile antenna
DXE 4 squares for 80 and 40 meters this month.
Happy New Year and 73,
Tim K3LR
http://www.k3lr.com
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