[NLRS] Trough reflector dimensions

Sat, 31 May 2003 16:30:15 -0500

a 6 ft is marginal at 1296 ....A 12 ft antenna at 1296 is very FB and even
works OK for 432 EME but is like 4 good yagis so needs 750 W at the antenna
to hear echoes. Working people takes less horsepower as there are alot of
big systems on the air.  I certainly do not recomment using a 10 ft dish on
432 EME but if you have it there it will work. Polarity change is easy this
way and is not easily done with yagis

I thought the original request dealt with "cellular" type sector antennas
that have that trough reflector configuration. Not sure how it got on big
dishes?

Barry VE4MA

---- Original Message ----- 
From: "Dr. Gerald N. Johnson, electrical engineer" <[email protected]>
To: "Brent Casavant" <[email protected]>
Cc: "Northern Lights Radio Society" <[email protected]>
Sent: Saturday, May 31, 2003 11:34 AM
Subject: Re: [NLRS] Trough reflector dimensions

> Reflector (focusing) antennas work poorly or not at all unless the
> reflector is at least several wavelengths and work better the larger the
> reflector. A 10' parabolic dish hasn't enough gain at 432 to account for
> the wind catching ability, and isn't as good as a halfway decent yagi
> design for gain. Takes 20 or 30' diameter of parabolic at 432 to work
> EME, its marginal at 1296 with 12'
>
> The dimensions seem right, to be inches.
>
> 73, Jerry, K0CQ
>
> -- 
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
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