[TowerTalk] 30 meter rotating dipole.

[Jim Thomson]

Date: Sun, 21 Aug 2016 22:27:57 -0400
From: Wayne Kline <w3ea at hotmail.com>
To: "towertalk at contesting.com" <towertalk at contesting.com>
Subject: [TowerTalk] 30 meter rotating dipole.

Never  had an antenna on 30 meters and the new little tower I am erecting  74'   has as Skyhawk triband antenna  @ 75'
I though I have this old F-12 rotating Dipole EF401 ??? not sure of the #  But
Why not a rotating 30 meter dipole 8 ft  above the Triband Antenna.
So....... has anybody  modified a F-12 40 meter dipole to 30 meters ?   
  
    Wayne  W3EA   

## IMO,  a 40m  rotary dipole would be far more useful  vs  30m.   However, it would be
an easy matter to convert any of the F12  40m rotary dipoles to 30m operation,  but this all 
depends on which model 40m yagi u have.   The  F12  40m linear loaded dipoles  I have use
44 ft long eles.   Without the LL wires, the ele alone should resonate aprx 10.7 mhz. 

##  For 30 m operation,  I would toss the LL wires, and replace  with a single dacron .1875  line
on  each ele  half, to support the ele  halves.   Where the fiberglass  insulator is located, half 
way out  each ele half,  either bridge the insulator with a piece of strap, or bridge it with a 
U shaped stub.   IE: 1-2 inches down,  few inces across, and back up  1-2 inchs.   Then the ele
will resosnate where you want it, like 10.125 mhz.   It should only require a 1:1 choke  balun and 50 ohm coax.
the hairpin should not be required. 

##  If the 40m dipole is the shorter  aprx 37 ft eles,  same deal,  except your stub will have to be bigger, that or replace the
stub with a small  coil.   In the case of the shorter 40m eles,  37 ft version, the hairpin will be required, but smaller than the
oem 40m hairpin. 

Jim  VE7RF