[TowerTalk] TowerTalk Digest, Vol 175, Issue 51

cqtestk4xs at aol.com cqtestk4xs at aol.com
Sat Jul 22 12:38:57 EDT 2017

Aloha Jim

The rotary dipole would be simple, but I have no more room on the tower.  Last set of guys is at 84 ft.  I have a 4 el 40 at 85, and at the top of the tower, at 94 feet is the tribander.  

Only about 5 or 6 feet will converge toward the tower since I have the ability to pull the ends of the ropes out a ways.  So it would seem that will not be an issue.  Again no way to know for sure.  I do have room for a rx array but I know about minimal distance.

In the end, I don't have many choices other than to put it up.  The location terrain and the resulting HFTA I've run for the Yagis is outstanding and I am hoping it will help mitigate any problems that arise.  I'm not expecting the optimal 25 dB F/B, and I can settle for less, since I'm using an rx antenna.  The main thing I want is gain and from what I've heard that isn't as easily degraded.  We'll see.  Lots of work ahead in any case.

73  Bill

##  The loaded 80m rotary dipole, may well be a lot simpler..and quieter. 
With a tornado drive on it, it will tune the entire band.   Feedpoint is right at 
the mast, so any CM choke, helical hairpin, coax is easy to get to. Mounted
inline with any  yagi booms above or below it, there is no interaction with other
yagis on the same mast.  Windload is a moot point, since with yagi eles  broadside
to the wind, the 80m dipole is pointed into the wind.  No snow or ice in KH6. 

##  The 80m 4 square, hanging from the tower, will have the obvious advantage of
instant direction switching.   I assume the tops of all the 80m verts  will converge a bit
towards the tower?   How much effect, if any, does that have ?       Do you have room 
for a dedicated 80m RX ant array ?  If any dedicated 80m RX array is used, then you 
also have to get the RX array a min distance away from the TX array.  

Jim  VE7RF


Message: 2
Date: Sat, 22 Jul 2017 11:56:00 -0400
From: K7LXC at aol.com
To: towertalk at contesting.com, keepwalking188 at ac0c.com
Subject: Re: [TowerTalk] Latteral load capability of T2X in mast
	mounted configuration
Message-ID: <14e5c.5e822a39.46a4cf90 at aol.com>
Content-Type: text/plain; charset="US-ASCII"

>  I am using a mobile crank-up / tilt tower for some antenna  testing that 
has a top section too small to get a ham4 rotor in.   Unfortunately that 
means I need to mount the rotor on a pole that extends from the top of the 
>  The good thing about this setup is the tower nests and the  tilts down 
essentially parallel to the ground, allowing you to mount the antenna  while 
standing on the ground.  The bad thing about that setup is the rotor  has 
got to be stout enough to hold the antenna weight while the rotor is  
temporarily horizontal.  
>  Would the tailtwister would be happy holding that much  weight off the 
nose when it?s temporarily horizontal?

I worked for Hy-Gain/Telex some years ago and  we destruction tested a T2X  
to determine the lateral load capacity (page  156 of my UP THE TOWER book 
available from championradio.com). The rotator took  3000 foot-lbs. before it 
broke. I'd say you shouldn't have a problem with your  proposed situation. 
Steve    K7LXC


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End of TowerTalk Digest, Vol 175, Issue 51

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