On Thu, 31 Dec 1998 17:29:11 -0800 "Larry L. Ravlin"
<sheepdip@continet.com> writes:
>
>What this all boils down to (and by the way you are absolutely correct
>in your figures) is "you are better off to sink you bucks into a GOOD
>antenna than a amplifier.
>this does not mean that I am against power, far from it, but there is
>More to gain from a good antenna than there is from a good amp.
>
>Larry K0AEY
Dollars per dB is a good way to look at optimizing station design
for a fixed or limited budget. The tradeoffs can get quite complex
and require ACCURATE and COMPLETE data. Don't forget the
cost of a tower and rotor. BTW, Higher is NOT ALWAYS better.
And, you can never have TOO MANY antennas!
The examples listed in the original post are somewhat misleading
and incomplete. The Alpha 91B is only ONE example.
One of the BEST VALUES in amplifiers is a used SB-220 at $400 - $600.
The SB-220 will produce 1200W on 80, 40, 20, 1000W on 15 and 900W
on 10M.
The Tribander gain example of 8 dBd is a JOKE, originating in the
advertising department.
8 dbd = 10.2 dBi which any antenna modeler can tell you
requires 5 elements on a 3/4 Wavelength (WL) boom.
A more realistic gain / boom table follows,
for FULL SIZE elements. These numbers
are not absolute as gain can vary +/- 1 dB
depending on element tuning for F/B ratio.
Trapped elements will have slightly less
gain and definitely less bandwidth.
Boom Element GAIN
WL NR dBi
0.15 2 6.5
0.25 3 7.5
0.35 3 or 4 8.5
0.40 4 9.2
0.50 4 or 5 9.6
0.60 5 9.8
0.75 5 or 6 10.5
0.80 6 11.0
1.00 6 or 7 11.2
de Tom N4KG
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