Dave Harmon wrote:
> Believe me.....the airport considerations are the LEAST of your potential
> and likely problems with a tower of any kind if you are in a sub-division or
> 'village' or 'township'.
> Any location where you must sign your rights away will probably make it
> impossible to do any HF operating of any quality.
Nonsense... You might not be able to use 1940s and 1950s technology
(i.e. a Yagi on a big tower), but from a theoretical standpoint, you
should be able to do almost as well from a 50x100x20 foot cube with
visually inconspicuous/invisible radiators.
The challenge to hams is to do "HF operating of quality" within the
constraints of modern civilization.
I'm sure the folks contemplating operation from a suburban lot with a
Yagi back in the 40s and 50s were probably told "if you don't have room
for a multiwavelength rhombic, you might as well be operating portable
on batteries"
And, of course, "nobody will ever use that newfangled sideband stuff"
I think that the era of "big tower with a 3 element yagi in the
backyard" is on its last legs, just like the multi-acre "antenna farm"
of yore (e.g. W6AM's installation). Of course, there will always be
folks with the resources to have the field of rhombics or the multi
tower with multi stacks (we can all dream), but the future is in fitting
in with other uses, and that means inconspicuous, making use of massive
signal processing, etc.
It's actually an exciting time. 20 years ago, adaptive interference
cancellation, adaptive antenna arrays, etc., were all the exclusive
province of folks with millions of bucks to spend on development and
signal processing hardware. Today, there's cheap processing hardware,
lots of clever software, etc. To take a concrete example.. today, any
amateur can go out and spend under $1000 and get RF measurement
equipment that can make measurements that would have required equipment
costing over $100K 20 years ago. (When did the HP 8510 come out? or
the 8573 VNA? how much did they cost?, etc.)
You can spend a few thousand bucks today and get hardware that will
allow you to build an 8 element phased array with performance that blows
away any of the wildest dreams thought of by the authors of the 1980s
antenna handbook.
Pretty much the only theoretical advantage of the tall tower (and it's a
significant one) is that you can get more radiated power into the far
field in a particular direction with a limit on transmitter power, and
that's mostly because of the soil properties a few wavelengths away.
Jim, W6RMK
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