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[Towertalk] Hy-Gain Explorer 7-3, Ring Rotor questions

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Subject: [Towertalk] Hy-Gain Explorer 7-3, Ring Rotor questions
From: (Jim White)
Date: Wed, 04 Sep 2002 14:11:07 -0400
I would recommend your removing the boom to mast attachment from Hygain, 
substitute a 2" Inside Diameter splice for the boom (Gerald/TX Tower) 
the splice can easily sit in the TIC far as your truss 
offset it slightly and attach it to the boom with a boom to mast 
arrangement - note you will need to be careful on clearance as the upper 
ends of the struts are now near the sides of your tower!

Recommend you re-build and then place it at the four foot level (work 
height) of your tower to give it a trial go - you can assemble it there 
(including the TIC Ring) and you will learn how to best handle the TIC 
which is a pain in the rear to install - you may be able to minimize 
your up top time also by having some of the pieces already bolted 

I had large boomed (3") home brew yagi which had a splice sleeve in the 
middle - unfortunately it was 1/4" thickness 3" ID and the resulting 3 
1/2" diameter boom was too big not to hit the tower legs on the 55G as 
it rotated - if it had the wind with it it would pop past the legs but 
more often than not it wouldn't and you would get stuck in a 120 degree 
range... I added some shimming and offset the antenna to avoid this 
problem - it a shame to take what was a nicely engineered system and 
have to kluge it up.

Also make sure you have the ring rotor working as you want it at ground 
level - these can be a royal pain to work on in the air - rotate it 
several times, etc. to be sure you got it dead on right - and remember 
which way you left it pointing and reinstall in the same orientation on 
the tower when you go up with it.

W6QHS had a post (yes he was QHS then) on this reflector years ago about 
how he suspended the feedline from above the antenna using a tractor 
trailer brake line spring (you see them on the back of the cabs) and I 
adopted that - worked great - this keeps the feedline away from those 
nasty gears which surely would eat up your coax. With the antenna at its 
mid rotation point (North?) attach the feedline and suspend the upside 
down drip loop with the spring - I used a snap link to a tower rung... 
when the antenna is pointed either side of mid rotation the spring will 
stretch and give you the needed length for the ends of the rotation (South?)

Don't get caught between the beam and the side of the tower when this 
baby is turning - the ring rotor develops a lot of ummph and I would not 
want to use my rib cage to stop it!


Jim, K4OJ

Jon Zaimes AA1K wrote:

> One of my top boom support cables on a Hy-Gain Explorer 7-3 snapped. These
> four cables are attached on the director and reflector elements, 10 inches
> out from the center of the boom.
> The manual specifies these be attached to the mast 5 feet above the boom.
> They are steel -- I'm not sure if it is stainless or galvanized -- without
> insulators.
> If the mast connection point is higher or lower than 5 feet, will this
> affect the tuning of the elements?
> If the cable is changed to a nonconductive material (such as Phillystran),
> will this affect the tuning of the elements?
> Also, I am getting ready to mount this beam on a TIC 1022 Ring Rotor (on
> Rohn 45, where it has been fix-mounted toward Europe). Since the Hy-Gain
> boom-to-mast bracket also serves as the coupling for the boom, I am
> planning to use some spacers (likely treated wood) to keep the boom high
> enough off the ring-rotor cradle so the bracket clears the cradle. The
> boom-to-mast bracket will also then be used to support a 5-foot mast to
> which the boom support cables will be attached.
> If anyone has used this type of mount, or has other thoughts on mounting
> this beam on a Ring Rotor, I wuold appreciate your ideas.
> 73/Jon AA1K
> Delaware
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