Ok.... I read the Antenna Handbook... it says to use a chart they have –
reading it at 52 ohms line impedance (coax)... and 22 ohms RL I need 42 ohms of
reactance.
Then shorten the driven element to produce enough capacitive reactance to
cancel out the inductive and transform the impedance up to 52 ohms.
So I enter 42 ohms as a center load in my driven element (6ft/-6ft length load
set to 50% and is 50% ... ) ... then shorten the length of the driven element.
But this doesn’t work. The load never gets transformed.
What I’ve been doing is enter their length/diameter info from their manual...
then adjust the driven element to get the SWR where I need it (centered) ...
then I read the load resistance off the SWR chart and change the “alternate’
source impedance to be this value. Finally I add in just enough hairpin to
cancel out any capacitive reactance. This works – I get the same SWR curves
that are published by M2 when I model their antennas... so I know its ‘right’.
But I can’t seem to now NOT use the ‘switch’ to a different line impedance in
order to determine the correct hairpin XL so I can figure out how to build the
hairpin!
any one see what I’m doing wrong please?
This is using EZNEC5
Gary
K9RX
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