24 Apr
2013
24 Apr
'13
4:10 p.m.
Stephen,
Thank your the advice on how to improve my satellite operation. Much appreciated, and exactly what I was hoping for when I posted the questions to the AMSAT BB. Tried it last night on a pass with mixed results. But I think I understand the principle now.
I'll also look for you on the birds---I need your grid! :-)
--
73,
Les Rayburn, N1LF
121 Mayfair Park
Maylene, AL 35114
EM63nf
6M VUCC #1712
AMSAT #38965
Grid Bandits #222
Southeastern VHF Society
Central States VHF Society Life Member
Six Club #2484
Active on 6 Meters thru 1296, 10GHz & Light
On 4/23/2013 4:40 PM, Stephen E. Belter wrote:
> Les,
>
> Here is the procedure I've used with SatPC32 and my Icom IC-821 for
> Doppler correction when operating SSB. It should work with any rig that
> is CAT controlled. (This is a corrected version of something I wrote a
> couple of years ago in response to a similar question.)
>
> Your success operating SO-50 is a good proving ground.
>
> Here is the approach I took:
>
> (1) Install SatPC32, enter your station's latitude and longitude, update
> the Keplarian elements, and synchronize the PC clock to a national
> standard like WWV/NIST.
>
> (2) Get your radio and SatPC32 communicating, and verify the operation
> (including Doppler correction) using an FM satellite (for example, SO-50).
>
> (3) Wait for a good pass of VO-52, for example 60+ degrees maximum
> elevation. I suggest VO-52 because it is the newest (compared to AO-7 and
> FO-29), it was more tolerant of using too much transmit power, and it had
> the smallest transponder correction. Note: This was true in 2011 with
> the Indian transponder. Since then the Indian transponder has failed and
> VO-52 is using the Dutch transponder which is not as tolerant of high
> power and isn't as frequency stable.
>
> (4) Open the "CAT" window. You can move the Window so that it doesn't
> block access to the main SatPC32 window. Tune the radio above the center
> of the satellite passband to reduce the QRM to other users. Make sure
> you are in SSB mode on the radio ("CW-" on SatPC32).
>
> (5) Using your call and "Test 1-2-3", listen for yourself while you are
> transmitting. You probably won't hear yourself at all, at least I
> didn't. Using the +100 and -100 buttons in the Transmit Correction part
> of the CAT window, try to find yourself. For VO-52, you should hear
> yourself within +/- 1500 hertz. (I think I was about +800, but that is
> from memory on the Indian transponder.)
>
> (6) Once you hear yourself using the +/-100 buttons, fine tune using the
> +/-10 buttons.
>
> (7) You can improve the tuning of your uplink/downlink using CW mode
> ("CW+" on SatPC32). Zero-beat the Icom's CW sidetone with your received
> signal.
>
> (8) *Save* the result by using the "Save" button in the CAT window. When
> given the choice, save the transmitter correction.
>
> (9) Verify that things are working by working a few VO-52 QSOs.
>
> (10) Repeat using FO-29 and AO-7, in that order. You may need to search
> over a wider frequency range (+/-3000 hertz).
>
> (11) One other important change when moving from FM to SSB. Your power
> output is important! Learn how to reduce your power and use the minimum
> power needed to hear yourself on the satellite. If you use too much
> power, you'll trash other conversations on the satellite and your
> transmissions will be badly distorted! This is especially true of AO-7
> mode B; you'll be able to hear the entire satellite passband modulated by
> a single CW operator running too much power.
>
> Good luck!
>
> 73, Steve N9IP
> --
>
> Steve Belter, seb@wintek.com
>
>
> On 4/23/13 3:40 PM, "Les Rayburn" les@highnoonfilm.com wrote:
>
>
>> I'm very new to satellite operation but have been having a blast for the
>> past couple of weeks. Using an IC-910H with attic antennas that include
>> a 7 element 432 Arrow
>> antenna with an SSB Electronics pre-amp mounted at the antenna. 1/2"
>> hardline makes the 70' run from the attic to the shack in the garage. 2
>> Meters shows a 6 element K1FO Yagi with an SSB Electronics pre-amp and
>> 1/2" hardline.
>>
>> Rig is controlled by SATPC32 via the CI-V interface at 9600 baud.
>>
>> On SO-50, I have no problems with doppler correction as you would
>> suspect. With the other birds, doppler is sometimes an issue. Sometimes
>> I hear stations strongly but when I call them, I don't hear my own
>> uplink and the other station obviously doesn't hear me either.
>>
>> On other passes, the difference is not so great, and I'll hear my own
>> uplink, though usually slightly off frequency.
>>
>> I know its possible to adjust the uplink frequency in the software, and
>> I've tried it during passes without much success. The translated help
>> file from German isn't much
>> assistance to me so far.
>>
>> Can someone on the list point me towards a better explanation on the
>> web, or offer suggestions on how to correct the situation? Any help is
>> greatly
>> appreciated!
>>
>>
>> --
>> 73,
>>
>> Les Rayburn, N1LF
>> 121 Mayfair Park
>> Maylene, AL 35114
>> EM63nf
>>
>> 6M VUCC #1712
>> AMSAT #38965
>> Grid Bandits #222
>> Southeastern VHF Society
>> Central States VHF Society Life Member
>> Six Club #2484
>>
>> Active on 6 Meters thru 1296, 10GHz & Light
>>
>> _______________________________________________
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>