At 07:08 PM 6/27/2006, Dino Darling wrote:
>New thread; lets hear about the portable phased arrays Jim!
Still in the tinkering stage.
Design criteria:
From wheels stop to fully deployed and on the air in <20 minutes. This is
a pretty challenging constraint, in itself.. No fiddling with hose clamps,
for instance. It gives you about 3-4 minutes to put up each element, and
another 5 minutes to hook it up and run the calibration.
Basic concept:
Simple vertical antennas (trapped or not.. I'm still doing experiments on
that, there's some interesting vertical angle tradeoffs between a trapped
vertical and a plain non-resonant vertical with a suitable matching
network), arranged in an arbitrary array.
{you might be in a roadside parking lot.. you just have to take what you
can get}
Array calibration (determining mutual Zs and relative positions of
elements) in-situ
{relays to connect cal signals to each element in turn, listening on the
other elements, etc.}
Computer controlled phasing networks to do the phasing.
Primarily the phasing approach is for transmit. On receive, I think you
can do better with suitable E-field probes, separate receivers, and lots of
DSP.
It's not going to be a 4 element SteppIR at 100 ft, but it should be
interesting. And, once it works for this, it's generically extendable to
all sorts of other applications.
Jim, W6RMK
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