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Tower Guys into antennas??

Nov 24th 2016, 15:22

K6NYB

Joined: Nov 20th 2014, 18:03
Total Topics: 0
Total Posts: 0
I posted back in June on this and got a few good replies.

Today I am asking for help on making the three or four guy wires that will hold my new 80 foot crank up tower, three or four sloping dipoles on 40 meters.

I understand I need to use insulating rope or cord from the top of the tower to the hot end of the dipoles, my question is, how long should that be?

How far away from the top of the metal tower does the insulating leader need to be before the top hot side of the dipole starts?? Please keep in mind that I will have an MA-5B on the top of the tower!!

Many thanks 73 and HAPPY THANKSGIVING TO ALL!
Nov 27th 2016, 20:26

AA6E

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
My sense is that the separation between end of your dipole and the tower is not critical. Being closer will detune the dipole somewhat (probably lowering the resonance frequency). On the other hand, you want the other end as high off the ground as possible -- for the same reasons. Maybe split the difference and put half of your guy rope above and half below the dipole. Keep in mind that your antenna system has to have all the physical strength you would want from a simple guy wire. I.e., make it strong.

Another approach would be to have a single dipole (or two dipoles at right angles) with the feed point(s) at the top of your tower with the legs sloping downward. This would increase the effective height of the dipole(s) -- maybe better than having 4 separate dipoles, and easier to manage.

73 Martin AA6E
Nov 28th 2016, 14:02

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Single support low-band antennas

Antennas with gain and good F/B can be a challenge on the low-bands. This is especially true if only one support, such as a tower, is available. It turns out there are a lot of relatively simple ways to build a vertically polarized array with very good performance. Half wave sloper arrays have many possibilities as shown in High performance half-sloper arrays , 1,104 kb, QEX Jan/Feb 2004. There are also a variety of other ways to go, as discussed in single support gain antennas, 415 kb, NCJ Mar/Apr 2003.
http://www.antennasbyn6lf.com/arrl_antenna_articles/
Dec 1st 2016, 22:47

K6NYB

Joined: Nov 20th 2014, 18:03
Total Topics: 0
Total Posts: 0
Thank you both very much!

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