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Re: Recommended ERPs ?



>X-From_: owner-AMSAT-BB@AMSAT.Org  Sun Jan  6 08:28:10 2002
>Date: Sun, 06 Jan 2002 12:02:32 -0500
>From: nick <ku2a@aspi.net>
>User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:0.9.4)
Gecko/20011019 Netscape6/6.2
>X-Accept-Language: en-us
>To: i8cvs <domenico.i8cvs@tin.it>
>CC: AMSAT-BB <amsat-bb@AMSAT.Org>
>Subject: Re: R: [amsat-bb] Recommended ERPs ?
>Sender: owner-AMSAT-BB@AMSAT.Org
>
>Hello Domenico,
>
>So I might be able to hear my 5W at the feed of a 45ele looper on 1269MHz.  
>I will have to try next time squint is low.  
>
>Thanks info, 73 Nick, ku2a

My experience on mode-L is less encouraging:

I run 15w out of my DEM 144/1268 Tx-conv. with about 9.5w at the 45-elem
loop yagi.  I find that produces a signal about 1 s-unit out of the noise
and about 2 s-units below the beacon.  It can be heard on SSB at low squint
angles if there are not too many Mode-U alligators about.  But when the agc
is suppressed by some of the guys running -3 dB from the beacon On Mode-U,
my mode-L is insuficient signal to garner any attention on SSB.  It will
produce an adequate CW signal.

It is my opinion that you will want a minimum of 15w at a 20dBi(linear)
antenna for ERP=15x100=1500w.  You should try for a min. of 2000w ERP
(which probably means mounting your L-band amp there).

The only other solution is a separate time period for Mode-LS when Mode-US
is disabled.  

Domenicos observations are probably correct for when you have no other
stations sharing the passband (thus downlink power budget)...reality is
that running -10 dB from the beacon makes you a "weak" station for most
(and not heard by quite a few).

The best I expect to do is get 14w at my antenna (using 6-foot run of
1/2-inch Heliax), unless I invest in a higher power Amp or add a second
antenna.

This experience is about three months old.   Just my experience,
Ed 

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