[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: AO-40 squint

I just finished building a 4.5 turn helix to test with my dish. Next pass where
I'm home to test looks like this weekend, I should know then if the additional
turns make an improvement on higher squints.


Don Woodward
AMSAT 33535

----- Original Message -----
From: "Frederick M. Spinner" <fspinner@hotmail.com>
To: <dbwoodw@abraxis.com>
Sent: Monday, March 18, 2002 10:47 AM
Subject: Re: [amsat-bb] AO-40 squint

Common "Helix" knowledge would say that with your offset dish which probably
has a f/d of 0.7 that you should be running a 4.5-5.5 turn helix for optimum

I just put in a post for an old Primestar dish, I'll let you know in a
couple of weeks what feed I'll use/what results I have with it.  It's
roughly the same as a 90cm offset dish in f/d, gain, etc.

Fred W0FMS

>From: "Don Woodward" <dbwoodw@abraxis.com>
>Reply-To: "Don Woodward" <dbwoodw@abraxis.com>
>To: "Amsat Bulletin Board" <amsat-bb@AMSAT.Org>
>Subject: [amsat-bb] AO-40 squint
>Date: Sun, 17 Mar 2002 08:26:41 -0500
>My current setup seems to capture 100% blocks/frames with good CRC's from
>when the squint is 20 degrees or less and the ratio of good to bad drops
>dramatically after the squint increases above 20, so I usually quit trying
>copy at this point - I am using a 90cm offset dish and a 2 1/2 turn helix
>Transystem 3733. My system hears very well - last week I was able to copy
>Helaps sideband noise. According to the "AO-40 S2 Squint Analysis by VK5HI"
>the AMSAT web, it says that "Optimal error free downlink performance using
>S2 downlink for telemetry captures occurs at squint angles less than 35
>My question:   Is anyone reliably coping blocks/frames with good CRC's at
>squints? Say 25 and up? How high?
>Don Woodward
>AMSAT 33535
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org


Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org