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Re: Once again: Realistic BBQ Dish Gain with OriginalDipole Feed, an



The real problem is with the Yaesu Rotors.  I've slowly started to convert 
my stuff over to satellite dish actuators, and it amazes me that a $50 TVRO 
actuator is so much stronger than a $650 ham rotor.

But as I've said before.  If I was having 60 MPH gusts (and that's nothing 
for Iowa) and/or I was not using the G5500 setup, I'd park the P* straight 
up.  Its not an option with that rotor and that size dish, it's a 
requirement.

Fred W0FMS


>From: "Jeff Griffin" <kb2m@comcast.net>
>Reply-To: "Jeff Griffin" <kb2m@arrl.net>
>To: "amsat BB" <amsat-bb@AMSAT.Org>
>Subject: Re: [amsat-bb] Once again: Realistic BBQ Dish Gain with 
>OriginalDipole Feed, an
>Date: Thu, 8 May 2003 09:01:53 -0400
>
>  I've had a BBQ dish up since day one. After the last round of BBQ dish vs
>bigger solid dish war's, I broke down and setup a 36" x 39" offset 
>PrimeStar
>dish. I then constructed a Helix and a patch feed for it. Yes my d/l went
>from an S-5 to an S-9 +, yes I can hear myself with 1 watt input (11 watts 
>=
>ERP of a 100), but the wind loading is definitely a big problem. We had a
>very windy spring here on the east coast, gust's to 60 MPH on several 
>day's.
>This caused me alot of grief with rotor re-alignment on several occasion's.
>I was outside watching my antennas (which are just 17' off of the ground 
>and
>observed a wind gust cause the rotor to turn without any power applied. It
>made sort of a whirring noise. I'm sure this is very hard on the gears. I
>went into my shack , turned on the rotor box and observed a 20 degree or so
>azimuth change from my normal park position. Another problem is with my 5
>year old fiberglass boom. The mounting point's at the dish are digging into
>the fiberglass and causing the dish to change it's mounting position. This
>is another case for using a metal boom, even if there is a slight loss of
>signal. Anyway it might be a better idea to simply cover the BBQ dish with
>screen , convert it to a circular feed via the Helix or patch feed. K5OE
>converted a BBQ shaped dish to a round one then covered it with screen, see
>his web site. I know this wind loading issue (solid same as screen covered)
>has been discussed here before but I had my BBQ dish up with screen on it
>and observed much less wind loading. None of the afore mentioned problem's
>I'm having with the PrimeStar occurred.
>  I, myself am going to experiment some more with the screen covered BBQ 
>dish
>with circular feed's. Also looking for a 8 foot plus dish to ground mount. 
>I
>would give the wind loading issue alot of thought......
>
>  > 1.) Windloading - the BBQ has a LOT less windload than a solid dish.
> > Jon
> > NA9D
>
>See you at Dayton.....
>73 Jeff kb2m
>
>
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