[TowerTalk] SterIR

[Joe Subich, W4TV]

On 2015-02-28 12:18 PM, Wilson wrote:
>
> I can’t imagine spending all that money to put that complicated
> antenna up in the air when an LPDA will do the same thing with no
> moving parts and, at most, 2dB of claimed gain.

A log-periodic is a poor third choice to a SteppIR or a multi-monoband
yagi.  The LPDA has minimal gain and F/B - it typically uses less than
30% of the boom length and unless it has a large number of elements
for the boom length suffers from wide SWR excursions.

Oh, by the way a dipole above ground has 8.1 dB of "gain" (8.1 dBi).
The Log-periodic - particularly the "sparse element" designs typically
marketed to amateurs - will be lucky to show 2 dBd (10 dBi) when
installed above earth compared to 13 - 15 dBi for a three element
SteppIR, or 11 - 12 dBi for a multi-monoband yagi on a 12' boom.  For
a Log-Periodic to even come close to matching the 3 element SteppIR
(16' boom) or multi-monoband yagi (12' boom) it will need to have
around 16 to 18 elements on a 30+ foot long boom.  The LP will weigh
four times what the multi-monoband yagi and have four to five times
the wind load of the three element SteppIR - just to cover 13.5-30 MHz
even though both the SteppIR and multi-monoband antennas can include
6 meters with no significant increase in wind load or weight.

73,

    ... Joe, W4TV


On 2015-02-28 12:18 PM, Wilson wrote:
> OK folks, now a word from our grinch:
>
> I can’t imagine spending all that money to put that complicated
> antenna up in the air when an LPDA will do the same thing with no
> moving parts and, at most, 2dB of claimed gain. And at HALF the
> price, with far lower maintenance liability. To each his (her) own,
> but I’d rather not have all that technology up in the lightning
> zone! It’s just no fun and the extra money will buy a LOT of beer!
> Yes, I could afford one, but my second hand TH-3 is making me quite
> happy. One of these days I’ll put up a log, when the WARC bands lure
> me... 73, Wilson W4BOH
> _______________________________________________
>
>
>
> _______________________________________________ TowerTalk mailing
> list TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>