Fwd: C-3 Info

[Pete Smith]

Hi Tony -- As always, I find your stuff sensible and thought-inducing.  But
the one place I don't agree with you is on the *magnitude* of the gain
advantage enjoyed by the KT-34XA. 

At 04:15 PM 1/14/97 -0500, you wrote:

(stuff deleted)

>3. As far as Force12 advertising claims, I'm skeptical. First, comparing
>a C3 to a KT34XA, the XA is really 4 elements on 15 and 20, and 5-6 elements
>on 20 [sic - think you meant 10]. If you check with the experts, or do some
modelling, >you'll find that the XA comes out 4-8 dB better in the forward
gain department.

(more deleted)

According to my modeling (all antennas at 97 feet):


20 M             C-3                     TH-7
                
Net Gain*       5.0 dB                  5.5 dB
F/B             10 dB                   18 dB

15 M

Net Gain        4.75 dB                 5.75 dB
F/B             12 dB                   24 dB

*Obtained by subtracting 7.5(20m) or 8(15m)dB from the dBi figures that
EZNEC produces, the approximate ground reflection gain of a dipole at this
height.

So you're saying that the XA beats the C-3 (or the TH-7) in forward gain by
more than a TH-7 beats a dipole at the same height.  I don't buy it. 2-3 dB
over the C-3 would seem more reasonable. 

As I told Pete, there's no way I'd swap my C-3 (actually, it's a C-4 now)
for a TH-7.  If the KT-34XA is, in fact, 2-3 dB better in forward gain than
the C-3, it'd be a harder choice.  But I like the design margins the C-3/4
gives me in all the other areas that are important to me  - weight, wind
area, and simplicity/reliability.


73, Pete Smith N4ZR
n4zr@contesting.com 
West (bigawd) Virginia


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