Bill,
Its really all about how much budget you have available for the guy wire
system and how much risk you're willing to accept that the performance
on one or more band will be degraded. You can always upgrade the guy wires
later if you want to defer the increaed expense until after you've
evaluated the performance of your antennas on each band.
Its possible that your antennas will performm well enough for your needs
with no insulators or Phillystran, but you're taking a chance that the
performance on one or more bands will be compromised.
Please tell us how long each set of guys will be.
Your minimum cost (and greatest performance risk especially on 80/160
meters) would be to use no insulators at all.
The next investment is to improve the top guys. Again, it comes down to cost
and performance risk. The most serious performance problems are
likely to be caused by the top of the guy wire nearest the Yagi. Since you're
likely to be using the SteppIr on 20, 17, 15, 12
and 10 meters, its not possible to remove the performance risk on all
of those bands with insulators. Your lowest cost solution is to
install Phillystran at the top of each guy. 30 or 40 feet of
Phillystran in each guy should remove most of your performance risk. If you
have budget for more, go for it!
If you still budget to do another set of guys, improve the middle guys with
either Phillystran or insulators. The minimal step is to add one
insulator to each guy. Install that insulator a few feet away from the
tower. If you have more budget, add another insulator to each guy
or -- even better -- install 30 or 40 feet of Phillystran at the top
of the middle guys.
The least performance risk comes from the lowest guys. If you still have more
budget, add an insulator within a few feet of the top of each guy. If you have
even more budget, use Phillystran or add another insulator to each guy.
Good luck with your new tower and antennas!
73!
Frank
W3LPL
---- Original message ----
>Date: Sat, 4 Aug 2007 04:51:42 -0500
>From: "bill rubin" <brubin2010@gmail.com>
>Subject: [TowerTalk] phillystran length ?
>To: towertalk@contesting.com
>
>I am planning to put up a 100ft rohn 45g with 3 sets of guys 1 at 94 ft. 2
>at 61ft, 3 at 31 ft.
>The antenna will be a steppir 3 ele. 6-20 meters and with 30-40 meter
>dipole option.
>also at the 85 ft level I plan on feeding my 80/160 fan dipole (inverted)
>
>Using a hybrid Phillystran 1/4 to EHS 1/4 configuration for the guys to
>reduce / remove guy resonance what should be the MINIMAL lengths be using
>the Phillystran ?
>
>Yes I know more is better, but budget wise i would like to know.
>
>Do I only need it at the top level ? Two levels ?
>
>Alternative if i use 502 insulators how many and where ?
>
>Thanks 73 N1HWC Bill
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