Ken,
There is a magical length which is about 40 ft. per side (plus/minus a
couple of ft.) that seems to work great on all bands (80 thru 10).
I've put this type of antenna up at least 50 times at different locations,
using all sorts of lengths due to space restrictions at some of the QTH's.
Let me show you my "subjective" results I got using three versions, all fed
with 450 ohm openwire:
1. 80m dipole (~65' per side)
2. Random doublet (about 40' per side)
3. 40m dipole (about 33' per side)
#1 worked well on all bands and I could certainly hold my own in pileups on
80 and 40. Of course you lose out to the stations with the beams on 20 and
above. Even matched on 160m with my matchbox, but was not very efficient
here. Hard to work DX on 160 with it.
#2 showed no noticeable difference in my ability to work multis in contests
or break pileups, regardless of band. Only downside was it did not match on
160m with my matchbox.
#3 matched all bands well, seemed to work just as well as #1 on all bands
40m and higher, but was distinctly less efficient when trying to work multis
or break pileups on 80m. For NVIS on 80m it seemed to be just as good as
#1.
Conclusion: Apparently you can reduce the size of the doublet up to about
35% without losing too much efficiency. Beyond that, you notice the
difference.
If you want, you can get out your modeling software and try to "prove" me
wrong (or right), but the bottom line is, after tens of 1000's of QSOs with
each of these, I have my opinion and I'm sticking to it!
73
Rick - DJ0IP
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Ken Brown
Sent: Friday, January 20, 2006 1:18 AM
Subject: [TenTec] twin lead fed dipole
EDIT EDIT EDIT
I know it is less than a half wave on 80 meters and more than a
half wave on 40 meters.
73 ES ALOHA DE KH6/N6KB
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