[amsat-bb] Re: actuator

[Edward Cole]

At 01:45 AM 5/28/2007, w7lrd at comcast.net wrote:
>Hello
>Has anyone tried an actuator for an elevation?  I have checked out-
>http://www.qsl.net/sv1bsx/actuator/actuator.html
>I want to add a four foot primestar to what I already have (2M 70M 
>and a 36x30 primestar dish.  With all this hardware I will be over 
>working my g5400.  I would probably have to replace the split 
>fiberglass boom with a longer metal one.  Then we get into the old 
>metal vs insulated boom.I have some old 'C' band receivers that have 
>actuator controls in them.
>

Bob,

Actuators are in common use for elevation with eme antennas (yagi 
arrays and dishes).

I use an actuator for elevation of my four M2-xpol-20 x-yagis (each 
21-foot long booms), plus I have two 12-foot 1296 and one 7-foot 902 
loop-yagis mounted inside the array.  The H-frame is 3" diam. 12-foot 
long cross-boom with 12-foot long 1.5" riser masts with fiberglass 
tips.  The elevation bracket weighs 70-lbs.  Total weight is probably 
well over 100-lbs. and the actuator handles it easily.  Lots of wind 
area in this 12x12x 21 foot mess.

On my satellite setup I use a 6-foot aluminum cross-boom (2m KLM-22C; 
70cm 435CP42) plus a 33-inch offset feed dish for 2.4 GHz.  No 
problems with use of metal cross-boom with antennas mounted in the 
"X" configuration (and feedline tied tight to boom and cross-boom).

I would eliminate the elevation part of the G5400 if you decide on an 
actuator.  In fact, before I got my B5400 I was using an used 
actuator arm on my satellite antennas (2m&70cm x-yagis).

Only caveat is that the actuator moves slowly and may not be fast 
enough to track Leos in overhead passes (I haven't actually made any 
calculation on this, though).

73,
Ed - KL7UW
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