Jim Thomson <jim.thom@telus.net> wrote:
> I only operate at night these days, so 20-10m is a wasted effort.
90% of my operation is at night. Retirement is a long way away. 20 is
occasionally
great, but I spend far more time on 40, 80, and 160, and I'd like to spend more
time on 30.
> The 1.5 kw amp is exactly 11.76 db louder than 100 watts.
> The 1.5 kw amp will work on TX on all NINE amateur bands....
> something the long boom, megabuck 20m yagi wont do.
> If station A cant hear station B, and vice versa.....and both
> are running 100 watts, the quick fix is to install a 6 to
> 11.76 db gain amp at both ends of the circuit. That's cheaper
> vs installing a bigger ant.
Bingo, Jim has nailed it.
> Tubing is still cheap at DXE. I just finished designing a full sized 3 el
> 30m yagi for a buddy. Eles start at 1.75 inch...then down to .375 at the
> tips.
> Good for 120 mph wind, and handles 1 inch of ice loading. 3.9 sq ft per
> ele. The full sized REF weighs 24.9 lbs..and less for the DE + DIR.
> Total cost for the tubing to build the 3 full sized 30m eles.... aprx 50.5 ft
> long for the
> REF, ended up being $366.30 ! Then the cost of the 30 ft boom, clamps
> etc, etc.
> So low band rotatable ants are doable, cost effective..and work good...for
> any
> part of the sunspot cycle.
Good job, Jim. You've got some great ideas there for antennas, and you've
helped
your buddy with some of them.
But notice that your costs assume that the ham already has a tower 50 - 70 ft
high
and a fairly heavy-duty rotor on it. That's where most of the money goes, not
into the
homebrew antenna.
I would be reluctant to put even a 40 meter shorty yagi on the mast that
supports
my 10 - 20 hexbeam. Even less an 80 meter dipole, which would overhang the
entire length of
the house. We get a lot of snow and ice, and significant winds.
And since hexbeams are some of the best-selling beams out there, a lot of hams
are probably looking at similar basic installations.
If you add up the cost of a 70 ft tower, heavy-duty rotor, good beam antenna,
concrete
pour, permits, etc., etc. it quickly shoots past the cost of a pretty solid
amplifier. And installing
it safely involves some significant skills that go well beyond installing and
operating an
amplifier.
73,
Cathy
N5WVR
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