Re[2]: HD rotators

John.Evans@comsat.com John.Evans@comsat.com
Tue, 7 Jan 1997 11:58:53 -0500


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Subject: Re[2]: HD rotators
Author:  John Evans at COR-FS5
Date:    1/6/97 3:57 PM


        Steve,
          My rotating tower system uses an HDR 300 rotator operating 
        at half-speed through a chain drive. My particular "war 
        stories" are that it would not hold the drive shaft provided 
        by RTS, which is 2-inch in diameter. I had to get a collar 
        welded on to increase the diameter to 3 inches to solve this 
        particular problem. My other difficulty has been with the 
        small screws that attach it to a mounting plate. Wind-induced 
        vibration of some of the antenna elements couples into the 
        tower and has twice caused these bolts to unscrew leaving the 
        rotator hanging by its control cable! (The reason it happened 
        twice is because I did not understand the cause the first 
        time around!) When it happened the first time, the fiberboard 
        cover was all smashed as well as the internal electronics. I 
        had an aluminum box fabricated to replace the fiberboard one. 
        This problem seems to have been solved by "Loctiting" the 
        bolts into their sockets! Other problems include the control 
        cable fouling the brake pall when first installed (resulting 
        in the coax loop being shredded and the readout pot being 
        smashed), and having to make harder keys. I am curious, 
        however, to hear if you ever built someone a propitch rotator 
        for this application? John N3HBX. 
     
     
     
     
     
     
     
        ____________________ Reply Separator _________________________________
Subject: Re: HD rotators
Author:  K7LXC@aol.com at INTERNET
Date:    1/6/97 12:23 PM
     
     
In a message dated 97-01-06 11:07:18 EST, W9UI@SprintMail.com (Bob Eslaire) 
writes:
     
>It would be interesting to know the reasons for your ordering, Steve.  
>What specific problems do the commercial rotors suffer from (I know all 
>about the HDR-300, as I have one and have to repair it often!).  
     
>HDR-300     The HDR-300 takes an off-the-shelve 1 RPM transmission and mates 
the indicator, brake, etc. to it.  It has the well-known keyway and related 
problems.  It's a "semi-HD" rotator.
     
> Yaesu G-2800  Another "semi-HD" rotor, it has reasonable rotating and 
torque figures but uses a conventional-type brake (non-worm gear) and has a 
weak mast clamp.
     
> Create RC5B3  This is a decent rotator.  It has a worm gear transmission so 
it doesn't need a brake, has substantial gears and a real nice control box.
 It's weakness is the cast aluminum mast clamp.
     
> Orion 2800    Now we're getting somewhere.  This rotator features a splined 
output shaft (no more keyway), worm gear transmission and the best mast clamp 
in the business.  The new digital control box has its quirks but does have 
presets and is computer ready.
     
> Prop pitch   Search no more for the BEST rotator even made.  One of these 
will turn your house and last 20 years or more.  Full-sized 80 meter beam?
 HA! No problem.  You have to either fabricate the control box and indicator
system yourself (not that tough) or buy the whole thing from Glenn, K6NA.
     
      By mere conincidence, TOWER TECH carries the Create, Orion and prop
pitch rotators.  We only handle the best.   
>
73,  Steve   K7LXC
     
     TOWER TECH -- professional tower supplies and services for amateurs
     
        CLAIMER:  My opinions are those of my employer.  So there.
     
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