[amsat-bb] Re: Should I abandon full doppler correction?

Sun Jul 24 16:42:48 PDT 2011

Tom,

I operated that same pass of FO-29.  I started with a nice conversation with Mike, WA8EBM (Michigan), then moved on to another nice conversation with Drew, KO4MA (Florida).  All three of us were using full Doppler control.  It was great.

I then heard you trying to chase W5BK across the passband.  It is a challenge, and good practice.  ;-)

I'm not knocking W5BK or any other operator who isn't using full Doppler.  It takes a lot of skill (a skill I never mastered) and there can be good reasons for using manual tuning (like running portable).  And I'm grateful for every contact I make, including with W5BK, WD9EWK, and ND9M, all of whom use manual tuning.

But I agree with Alan, if you're in a position to run full Doppler, do it!

73, Steve N9IP
--
Steve Belter, Indiana Dataline Corp
427 N 6th Street, Suite C
Lafayette, IN 47901-2211
Tel: (765) 269-8521
www.indiana-dataline.net

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Alan P. Biddle
Sent: Sunday, July 24, 2011 6:27 PM
To: 'Tom Schaefer, NY4I'; 'Amsat BB'
Subject: [amsat-bb] Re: Should I abandon full doppler correction?

Tom,

There was an article in the Journal a few issues back on why the various manual techniques are only approximations, sometimes surprisingly bad ones.
I think the author's call was WA4SCA.  So it does get talked about. With an accurate clock, and current Keps it is possible to work a full pass and scarcely touch the dial.  It definitely makes it easier to conduct a round table.  If the transponder uses either modes L and/or S, you really don't have much choice.  The change rate is just too fast for practical manual running, though VE3NPC does an amazing job.  Even FM, which is very forgiving is a challenge for manual tuning at those frequencies.  

My default is for full Doppler correction.  If the other station is using it, fine.  We can concentrate on communicating.  If not, I switch off and do it the traditional way.  It does provide some gentle encouragement to try a new method, and gives you an opportunity to spread the word.  I am embarrassed at how long I stuck with paper logs amid all this technology.  I experienced a lot of nostalgia when I transferred all my old satellite contacts to electronic format, but I have never looked back.

Hang in there.  As time goes by, you will see more stations using it, as they won't have to unlearn years of experience.  Just remember that it is a hobby, and there are many for whom tuning and pointing are an integral part of satellite operations.  Have fun!

Alan
WA4SCA

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Tom Schaefer, NY4I
Sent: Sunday, July 24, 2011 4:17 PM
To: Amsat BB
Subject: [amsat-bb] Should I abandon full doppler correction?

Hi all,

I just tried a nice pass on FO-29. I heard K9CIS on CW and W5BK from Texas.
In both cases, while I am using full doppler correction with my 9100 and MacDoppler, I suspect they are leaving the transmit frequency fixed as they both changed frequency. K9CIS on CW was quite extreme in the Doppler shift.
I know that this is a by-product of me using full doppler to listen to stations that are not, but it seems that the majority of the stations I hear are NOT using flu doppler. I have asked this question before, but it seems to be happening more frequently.

Should I abandon full doppler correction? Another less black-and-white step is that if I hear a station moving to adjust my settings so I am not doing full doppler. 

Has anyone ever taken a survey to see how many satellite users actually use full doppler. Am I assuming more guys use computers and anyone of the multiple ways to do computer control that have ben available for years? Does anyone ever talk about this in AMSAT circles? Sort of like the encouragement one gives to people afraid of LOTW to try it? "Computers in the shack.NEVER!" I exaggerate but it seems that way. Then again, being a computer person and having computer capable rigs I realize I am skewed in my expectations. I know there are guys working with old 271/471 pairs or even the old FT726 out there. Great radios and a simple way to do it, but even they have ways to do full doppler control and they have been out for 20 years. 

Thanks,

Tom
Tom Schaefer, NY4I
ny4i at arrl.net
EL88pb
Monitoring EchoLink node KJ4FEC-L 489389 DSTAR Capable  APRS: NY4I-15

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