[TowerTalk] CDE ANTENNA ROTOR

[Kenneth D. Grimm]

THOMAS E. DE HOFF wrote:
> 
> TO ANY AMATEUR OPERATOR
> I AM TRING TO LOCATED INFO ON THE CDE HAM-M ROTOR
> WHAT INO I NEED IS THE SURFACE AREA THAT THE ROTOR WAS RATED AT FOR
> HANDLING WIND LOADS------------I WOULD APPRECIATE ANY INFO OR JOURNAL
> REFERENCE THAT HAS THIS INFORMATION---------
> TNX TOM WA7MAL-----
 
You ask an interesting question, Tom.  One that is rather difficult to
answer, I'm afraid.  The spec. sheet put out by Cornell-Dubilier, the
original manufacturer of the HAM series of rotators, does not mention
surface area or wind load.  The two items of interest are that it would
"support 1,000 lbs. of dead weight" and the brake was rated at "3,500
lbs. of torque from wind pressure."  The Ham IV carried a rating of 15
sq. ft. of wind load when mounted inside a tower.  This rotor was
essentially the same as the HAM-M, but with a couple of significant
improvements.  The ring gear and brake were improved and made of harder
material.  By inerence you would need to derate the HAM-IV figures for
the HAM-M.  Norm's Rotor Service has done a good job of compiling and
interpolating this kind of information and he suggests a rating of 10
sq. ft. for the old HAM-M.  This sounds very reasonable to me.  You can
check out his comments on the old rotators on his web site at
http://www.tiac.net/users/shiacawn/rotors/

73,
Ken K4XL
grimm@alison.sbc.edu

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