[TowerTalk] New antenna system

Joe Subich, K4IK k4ik at subich.com
Mon Nov 8 23:03:14 EST 2004



> 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 
boom. 

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). 

73, 

   ... Joe, K4IK 
 




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