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RE: Help with L1 uplink on AO-40



Gary

Interesting to hear this for L1 which I have no experience.  Your 12-foot
dish is providing around 32-dBi gain (is the Tri-feed circular or linear
polarity?) so this multiplies your power by 1585 to get an EiRP = 3170w.
Is the 2w measured at the dish or radio end of the 75-foot run of coax?  If
at the radio end, then the EiRP will be around 2000w (10w would give EiRP =
10,000w).

The reason I find this interesting is that is very close to my estimate for
"good" uplinking to AO-40 on mode-L.  My experience was with L2 over a year
ago using 9.5w at a 45-element loop-yagi (20 dBi-linear pol) which was
marginal (EiRP= 950w).

My current plan is 14w at a 28 dBi dish (8-foot) for max EiRP = 8800w!
Always can turn down the juice!

I bet you hear AO-40 nicely with the big dish!

73, Ed - AL7EB

At 09:41 AM 1/5/2003 -0800, Gary Gonnella wrote:
>I was on L band last night around 4:00 to 5:30 UTC I was working L1 with no
>problems. I have a 12 foot dish with a tri-band patch feed and feeding it
>with an IC-910H at about 10 watts through 75 feet of LMR600. At this time
>the squint was about 18 degrees and decreasing to 12 or so. The L band
>appears to be more sensitive to squint than U band and I need to run 10
>watts down to about 10 degrees, then it decreases it until I only need about
>2 watts below 5 degrees. Hope this helps.
>
>Gary Gonnella W6RYO
>gary@w6ryo.com
>http://www.w6ryo.com
>
>
>> -----Original Message-----
>> From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
>> Behalf Of Joe Steinmetz
>> Sent: Saturday, January 04, 2003 10:32 PM
>> To: amsat-bb@AMSAT.Org
>> Subject: [amsat-bb] Help with L1 uplink on AO-40
>>
>>
>> Hello,
>>
>> I am debugging my ground station for AO-40 and was wondering if
>> someone who
>> might have been using the L1 uplink tonight could tell me how well it was
>> working? I was just barely able to hear myself on the downlink, however I
>> could hear the beacon and many others well above my signal level. I am
>> assuming that my receive setup is OK since I could hear myself (in the
>> noise) and others (well above the noise) and the beacon (very strong).
>>
>> At the time of my experiment (1/5/03 05:00 - 06:00 UTC) the
>> squint was about
>> 12 degrees (assuming I set Nova up correctly).
>>
>> I am thinking that I have a serious uplink problem. I have two
>> 12-turn-helix
>> (RHCP) phased for approx 17dBic of gain, with about 60 feet of LMR-400
>> ultra-flex and a SSB 80watt amp feeding the system. I am loosing 3.4dB in
>> the cable run and according to my directional wattmeter I am
>> getting 2 watts
>> reflected. Could something be wrong in the phasing that wouldn't
>> show up as
>> a reflected energy? I am thinking of swapping the phased helix out and
>> replacing it with a 22 element yagi just to help isolate the problem.
>>
>> I only plan on running enough power to get my signal 8dB below the beacon,
>> but right now, I am way below that.
>>
>> How much power are others using for their L band uplinks? And what antenna
>> (and gain) are you using?
>>
>> Any thoughts?
>>
>> Joe
>> k6sat
>> ----
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>
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