Topband: Tuning Christman Phasing
Kenny Silverman
kenny.k2kw at gmail.com
Sun Sep 18 23:30:47 EDT 2022
I’m planning a 2ele 160m array using the Christman phasing method. Each vertical will be about 80-90’ tall hung from trees, each using 2 sloping top-loading wires. I assume the elements won’t be exactly 90 degrees apart, but I could slope 1 element so the bases are 90 degrees apart.
Are there any tips or guidelines on how to tune the array? For example:
- adjust each vertical wire to the same/similar height? (Impacts impedance and bandwidth of each element)
-if the elements aren’t spaced exactly 90 degrees apart do the phasing lines need to be adjusted? (I wouldn’t have a clue how to adjust so the voltages are the same with changed lengths)
- Tune each vertical with the other out of the system?
- lay enough radials so each vertical has a similar impedance? (I’m planning on 60 x 100’ radials for each element, but can add more to balance the impedance)
- tune each vertical to the same desired center freq? (1.840 for example)
- impedance match each vertical to 50 ohms (using hairpin coil or toroidal transformation)?
- use a 1:2 toroidal transformation at the phase line junction?
-Other?
Thanks, Kenny K2KW
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