[amsat-bb] Re: Tuning

[Art McBride]

For the linear transponder Satellites I have found with my IC 820H using the
main tuning dial to adjust receive and switching that side and adjust for
transmit works the best during Field Day operations. The I-Com is just to
clumsy to use the sub receiver, RIT does not have enough range, no easy way
to adjust the offset, transmit power, ETC. I calculate the offset VS time
using Instant Track in advance and work off of paper data. I set the
elevation of the mast to match the pass and a single rotator performs both
elevation and azimuth functions. 

If we had a HEO I would consider buying something better than the 820, but
for now I drag out the old 820 and make a few contacts for W6NWG each year
at FD, and that is the extent of my satellite activity. 

Art,
KC6UQH   

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of James Duffey
Sent: Saturday, April 18, 2009 7:18 PM
To: Jerry Felts
Cc: Amsat BB
Subject: [amsat-bb] Re: Tuning

Before the advent of computer Doppler tuning compensation, the  
convention was to tune the radio on the highest band as that is where  
the doppler is the largest and to leave the other one alone as much as  
possible. That is not a perfect solution as different stations in the  
footprint see different Doppler shifts and it is usually unavoidable  
to tweak both radios. But you can generally save yourself a lot of  
confusion by only tuning one radio, the highest one, whether it be  
receive or transmit.

If you are using a computer for tracking, it should also give you the  
doppler correction even if you are not controlling the radios with it  
and you should find your downlink without too much trouble. It is  
confusing at first, but after a while you get hte hang of it and it  
becomes second nature.

If you can catch AO-7 in Mode A, that is a good mode to practice  
Doppler compensation with as the doppler shifts are much lower. - Duffey


On Apr 18, 2009, at 12:07 PM, Jerry Felts wrote:

> I have made 2 contacts now both were  VO-52. Both times on SSB and  
> very
> confusing. So say I'm working you. I found a clear freq by sending  
> alot
> dots. The uplink tx is switched to LSB. Do I leave the tuning dial  
> on the
> uplink rig and just use the tuning dial on the downlink to do my  
> tuning? Or
> do I juggle both rigs tuning dial and get confused?
>
> Jerry - NR5A - South Dakota
> www.freewebs.com/nr5a
> http://groups.yahoo.com/group/Minimalist_QRP_Transceivers/
> http://www.cakewalkblogs.com/nr5asminimalradio/index.aspx
> http://nr5abeaconblog.blogspot.com/
> _______________________________________________
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--
KK6MC
James Duffey
Cedar Crest NM





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