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Re: AO-51 Mode L antenna question



Thanks Drew!

To summarize the article:
Minimal results (Not a good choice in my opinion):  EIRP = 150w
Medium results (lowest one should use) EIRP = 500w
Best results EIRP > 1000w
----------------------------------------
EIRP = power x antenna gain (ratio not dBi)
So the typical 1.2 GHz radio generates 10w at the radio coax terminal
using the coax loss calculator cited in the article:
50-foot LMR-400 will result in 5.8w at the antenna
using a 20-dBi antenna you get x100 gain ratio
EIRP = 5.8 x 100 = 588w

The Directive Systems: http://www.directivesystems.com/
LY2345K loop-yagi = 20-dBi  $120.00
it is 12-foot long.
It will work at 1268 MHz though speced at 1296.
---------------------------------------
For a mobile* operation let's say your coax is 15-foot of LMR-400:
you have 8.5w at the antenna
using the LY2325K loop-yagi = 17-dBi  $88.00
it is 6-foot long
EIRP = 8.5 x 50 = 425w

Sound good?
*Note:  I hope by mobile you mean you drive to this nice open parking lot
and set up your stuff.  Operating while driving on L-band will take some
power thru a 10-dBi patch antenna.  (e.g. ~50w).

Now, other folks make 1.2 GHz antennas.  I also like M2 Antennas.

Hope that helps you figure out things, Ron
73's Ed - KL7UW
PS: my 1268 system runs 15w, 4.73 dB loss, 23-dBi gain (2xLY2345) for EIRP
= 5 x 200 = 1000w
or I can add my 60w PA: EIRP = 20 x 200 = 4000w!

At 10:31 PM 10/8/2005 -0400, Andrew Glasbrenner wrote:
>Well, not from my email, but here it is.
>
>http://www.amsat.org/amsat/archive/amsat-bb/200408/msg00469.html
>
>73, Drew KO4MA
>
>-----Original Message-----
>From: Andrew Glasbrenner <glasbrenner@mindspring.com>
>Sent: Oct 8, 2005 9:30 PM
>To: rnutter@networkref.com, AMSAT BB <amsat-bb@amsat.org>
>Cc: n1jez@amsat.org
>Subject: Re: [amsat-bb] AO-51 Mode L antenna question
>
>Hi Ron, 
>Mike Seguin, N1JEZ put together a bunch of reports of stations used for
the L uplink on AO-51 last year. I think you could get a good handle on the
EIRP requirements from that. I'll see if I have that email on my other PC
and forward it on...
>
>73, Drew KO4MA
>
>-----Original Message-----
>From: Ronald Nutter <rnutter@networkref.com>
>Sent: Oct 8, 2005 4:45 PM
>To: AMSAT BB <amsat-bb@amsat.org>
>Subject: [amsat-bb] AO-51 Mode L antenna question
>
>I am trying to find an antenna for Mode L use on AO-51.  My main focus
>is to be able to use Mode L/S mobile like I can Mode V/S.
>
>Suggestions ?
>
>Thanks.
>
>Ron
>KA4KYI
>
>
>-- 
>No virus found in this outgoing message.
>Checked by AVG Anti-Virus.
>Version: 7.0.344 / Virus Database: 267.11.13/124 - Release Date: 10/7/2005
>----
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73's,
Ed - KL7UW  
=================================
http://www.qsl.net/al7eb
144-MHz EME - BP40iq:
FT-847, mgf-1801/1402, 4xM2-xpol-20, 170w
=================================
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