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Re: About Last Night...

Hi Jim,

Interesting.  I found last night's pass stronger than most.  Usually
I hear stations on the transponder just above the noise, and have to
struggle to copy.  Last night wasn't exactly armchair conditions, but
I could actually relax and have a conversation.  Squint here was about
9 degrees, if I recall; MA somewhere around 135.  But, no trees in
the picture.  That makes a big difference on the downlink, and not
so much on the uplink.  Leila can hear you fine, even when you can't
hear her.


Greg  KO6TH

>From: "Dr. Jim Akers" <jakers@ECE.MsState.EDU>
>To: amsat-bb <amsat-bb@AMSAT.Org>
>Subject: [amsat-bb] About Last Night...
>Date: Sat, 8 Sep 2001 15:27:15 -0500 (CDT)
>Hey gang,
>Great pass last night but I am a bit puzzled by some things I observed my
>system doing....or not doing.
>Here's the line-up:
>BBQ grill antenna
>UEK 3000
>Uplink:(U band)
>100 watt brick (if needed)
>50 feet of flexi IV (same characteristics as 9913)
>Homebrew helix with 10 turns...low VSWR
>Now here's the problem.
>The beacon never got above about S-3 even though the squint was very low.
>Signals on the transponder were weak but some were readable and I did make
>a few contacts.
>Before you say that the system is just deaf, be advised that I could copy
>my own downlink (on cw)with only about 1 watt at the antenna at MA 114.
>At MA 128, I could still *detect* my downlink (on cw), both by ear and
>seeing it on AO40rcv waterfall, with less than .2 watt at the antenna!
>That was more than 61000 Km away and I was looking through some trees.
>There were no trees in the way when the beacon was S-3 at about MA 47 or
>so.  According to the W3PM spread sheet, I should have been seeing a S/N
>of almost 20 dB on the beacon.  It was more like 6 or 7 dB if that much.
>I seem to be adding 2+2 and getting 3;-)  What are those of you using a
>similar system seeing?  It just seems to me that I should be hearing the
>beacon and transponder better than I am.
>I see about 2-3 dB increase in noise from cold sky to pointing at nearby
>trees.  This seem about right?
>I think I set Leila off one time when raising the power for test purposes
>but it was hard to tell with the idiot with the recording on the loose.
>He must, at least, have a good receiver because he found me several times
>when I was experimenting with only 1 watt!  It's too bad he gets his kicks
>that way instead of making contacts.
>Dr. Jim Akers
>Dept. of Electrical
>and Computer Engineering
>Miss. State Univ.
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

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