Re: [amsat-bb] Once again: Realistic BBQ Dish Gain with OriginalDipole Feed, an

["Frederick M. Spinner" <fspinner@xxxxxxxxxxx>]

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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