When I just got started in VHF roving about 4 years ago, I thought the log
periodic made sense too. I purchased one, but am embarrassed to admit I didn't
realize it was a bit too wide to be taken pointing forward at 118 inches. The
6.6 ft boom might fit sideways, but you'd have a lot of mount torque at highway
speeds, and maybe you'd need to mount it at an offset from vehicle centerline
since the antenna mount is not centered on the antenna boom.
Besides this, you need to switch in bands either manually or with relays.
Losses and costs in switching components get worse and worse as you move up in
frequency. If you're starting with one of the radios that provide 3 VHF bands
(50, 144, 432), that won't be a problem if you start on just those 3 bands, but
as soon as you add another one (222, 903, 1296), you have to deal with
switching those bands into the antenna.
For all this complication, you get mediocre to poor performance compared to
similar length single band beams.
I'll be interested to hear what more experienced VHFers think on this reflector.
-- Pete K0BAK
From: Ed via VHFcontesting <vhfcontesting@contesting.com>
To: vhfcontesting@contesting.com
Sent: Wednesday, September 13, 2017 5:59 PM
Subject: [VHFcontesting] Log Periodic ?
I am considering a Create LPDA for a roving station. Thinking it'll sit nicely
on the roof of my fifth wheel. This would allow me to work all bands from 6m to
1.2 Ghz with a single antenna. I can also change the polarization for FM.
Thoughts?
73,
Ed NI6S
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