All great advice. And even 1.5 dB can be the difference.
73, Jim K9YC
On 1/27/2022 9:19 AM, VE6WZ_Steve wrote:
Be aware that the gain and F/B of the array is very sensitive to parasitic loss.
Ground loss will quickly diminish the current in the parasitic and the gain
will crash.
It’s easy to model this. Just include a series resistance in the parasitic
element and watch the gain and F/B drop.
Field measuring the gain with on air tests can be difficult. With only 3 or 4
dB forward gain compared to the single vertical, it can be very hard to
measure. Even using RBN reports, QSB can easily mask this small change.
However, 3 dB is, well…..3dB and it's like doubling your TX power. For the
really weak QSOs, when your signal is just bubbling around the noise, that 3dB can
make the QSO.
I recommend you read about my tuning method. It is not a trivial process to
tune the parasitic to match the model.
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