[antennaware] L-match component specification
Mon, 11 Jun 2001 21:54:18 +0100
Last winter I installed a 105ft vertical at my alternative location based
on a modified version of the titanex 160HD. I fed it through an L-match
comprising a coil from antenna to earth and a capacitor from the antenna
to the 50ohm coax feeder. I was able to match it easily on both 160
and 80 and it worked very well.
Changing bands or moving up from 1.835 necessitated going to the
base of the antenna and changing coil taps and capacitor values.
I want to put in remote switching before next season.
I would like some help in three questions so that I can select
relays and capacitors that will withstand the voltages and currents
that will exist at different frequencies and power levels.
1) I would like to be able to work out the voltage across, and current
through the series capacitor at different power levels and at
different frequencies. Are there any standard formulae I can use?
2) I know there are a few circuit analysis programs around, does
anyone know of a suitable shareware program? I would like to
be able to investigate all the voltages and currents.
3) I am also not sure how to represent the complete circuit to include
the antenna load and the 50ohm feed. Can anyone help?
The figures I have from modelling are as follows
1.85MHz with 400w input
Source imp = 20 - j100
Voltage = 456 @ -79deg
Current = 4.5A @ 0deg
Coil = 6uh
Cap = 560pf
3.65MHz with 400w input
Source imp = 409 + j485
Voltage = 627 @ 50deg
Current = 1A @ 0deg
Coil = 13 uh
Cap = 202pf
Thanks in advance for any help or advice,
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