[TowerTalk] More on Array's from N0AH

[Dick Green]

A couple of quick followup comments on Paul's followup:

1. I use a 1.5KW dry dummy load for dumped power (memory is failing, but I
think I got it from Comtek.) It's outside and well ventilated, and the math
says I'm dumping 50W or less under normal circumstances. I don't think an
oil-filled 1.5KW unit is necessary, but a 300W dummy load would probably get
too hot with full-power RTTY or at the band edges.

2. On dumping power into a dummy load versus radiating it: I don't want to
start an e-mail war here on whether power is lost when there's a mismatch
(I've seen identical endless arguments on this subject both here and on the
AMPs reflector.) I'm in the camp that says SWR doesn't cause power losses
unless the feedline is very lossy or the SWR is *really* high. In other
words, the reflected power gets radiated by the antenna and doesn't get
dissipated in your rig. So I would say that a 4-square with a hybrid coupler
loses some radiated power by diverting the reflected power to a dummy load,
whereas the parasitic array with high SWR radiates that reflected power.
However, I'm not going to sweat losing 50W out of 1500W. I can barely get
that resolution on my power meter!

73, Dick WC1M


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