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Re: Getting ready for mode L/S



Ken

My experience of mode L uplink with an original G3JVL loop yagi, and
slightly lower feeder loss than you,  was that 10W was enough power to make
contacts with some of the better equipped stations (downlink-wise) but
would get me nowhere near -10dB relative to the beacon. 

I switched over to a 5ft dish with linear pol which was much better, but
still not quite enough on "bad squint" days.  I'm hoping to improve that
system by 3dB with an RUH feed, scaled to 1269.

73

Charlie G3WDG

At 17:47 17/07/01 -0500, you wrote:
>Since transponder operation on AO-40 is on the verge of reality (again), I
>am working on commissioning a Mode L uplink.  My antenna will be a Directive
>Systems Loop Yagi Model 2345LYK.  Gain specified is 20 dBi.  The radio is a
>FT-736R with 1.2 Ghz module with nominal output of 10 watts.  My
>transmission line will be approximately 50' of 7/8 in heliax with 5 to 10 ft
>lengths of Belden 9913 on each end.  I am calculating about 3 to 4 db of
>transmission line loss.  My question is this:
>
>Will I need an additional power amp?
>
>My EIRP should be about 10 watts  * 100 * 0.5 = 500 watts less about 3 db
>penalty for linear polarization or about 250 watts.
>
>Any comments?
>
>73 de Ken
>K5GUU
>
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