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19" vs. 5/8 L antenna



Hi Bob!

Am Sonntag, 23. Dezember 2001 09:00 schrieb bob <mail@nadn.navy.mil.
> Date: Sat, 22 Dec 2001 13:53:42 +0000 (US/Eastern)
> From: bob <mail@nadn.navy.mil>
> Subject: [amsat-bb] PCsat mobile OPS
>
> I rarely get to operate PCsat mobile but being on XMAS travel, I got to
> listen to 3 passes yesterday.  I was very disappointed at my reception on
> my 5/8 wave normal mobile set-up with my D700.  I quickly put a 19" whip
> on my D7 HT and held it out the window (in 25 deg temps) and copied PCsat
> almost 10-to-1 better!
>
I agree with you. I recognized similar results in testing several antenna 
forms on my car. The 19" whip almost with a magmount is the best. I got very 
good results when it was located on the trunk of my car. The elevations of 
the observed orbits where between 20° and 75°.
A very bad s-meter reading with nearly no decoded frames I got with a 
dualband mobile antenna with a coil in the middle of the whip.....I don`t 
know why! Perhaps the antenna was not ok ....

> Now I konw that the 5/8 wave has a null above about 15 deg and then a
> - - 6 dB lobe above about 45 degrees, but I thought its better gain at the
> horizon would help when PCsat was low (40% of a pass is below 15 deg)...
>
> PCsat was designed to wrk with an HT (it does) but this mobile performance
> was a shock.  Maybe its just my rat-shack antenna?  ANyone else have any
> experience on their mobiles?
>
The original rubber antenna on the TH-D7 is a real dummyload with no gain. A 
(for me unknown) flexible whip with a BNC connector of about 38cm length has 
very good results when working with 2m satellites.

Bob,  Merry X-Mas and a Happy New Year! Thanks for APRS and PC-Sat to the ham 
radio commiunity!

de Wolf, oe7ftj
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