> I can agree with most of your remarks excepting one : "the
> boom length has been compromised slightly". I don't think
> that "slightly" is the right word in this case.
"Slightly" is most certainly the right word.
If one were designing for > 20 dB F/R on 10 meters, a four element
antenna would have a 24 to 26 foot boom. The four element SteppIR
uses a 32 foot boom ... it maintains 20 dB F/R through 12 meters.
However, it also achieves about 1 dB better forward gain through
all of 13.9 - 30 MHz than would have been possible with the shorter
Similarly, if one were designing a three element antenna for 20 dB
F/R it would have a 12 foot boom. As it is, the three element
SteppIR trades about 5 dB F/R on 12 and 9 dB F/R on 10 for an
additional .5 to .7 dB gain across the operating range. That
seems to be a good tradeoff ... since the measured F/R of 15 dB
on 10 is in the same ballpark F/B measurements for any of the
tribanders tested by K7LXC and N0AX in the HF Tribander report
(using the same test protocol).
... Joe, K4IK
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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