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RE: Full Duplex Mode in Station Program



Hi Paul,

Is STATION 2 ready to download as a Beta test now?
I've been using my Yaesu FT-847 with FDT in station 1.
Works pretty good.  Only problem I have is the CAT does not
turn off whenever I leave the program.  I might have mentioned
this earlier, but wondering if that's fixed in STATION 2.  I'm
anxious to try it out.  BTW, I forwared a copy of your earlier
message concerning the CAT working only one way.  Maybe
they will fix it.

Thanks much,

73 de Bill, N4DH


At 10:17 AM 6/8/98 -0300, Willmott, Paul wrote:
>Graham,
>
>The FDT (Full-Doppler-Tracking) part of Station is currently  a
>"technology demonstration". It works in its way, but its not yet really
>sorted out user interface wise. This is simply because I need a lot more
>time on a high alt bird to develop it, I coded the FDT option a few
>weeks before AO-13 went off the air, and since then AO-10 has not been
>good from my QTH. I tried using FDT on the LEO birds, but the passes are
>too short for development work.
>
>Having said all that let me tell you my future plans and then how
>everything works now.
>
>I'm currently writing Station 2, this is the 32 bit version, and is a
>150% rewrite. Station 2 includes the SGP4/SDP4 models (as well as PLAN13
>that Station 1 uses). These models will give a much better start point
>for full Doppler correction.
>
>I agree 100% that fixing at the transponder is the way forward, indeed
>it may be the only way to work with 3D given the 24GHz and 10GHz
>downlinks on at the same time as say 2m.
>
>Station 1 was designed to control Icom radios, the Icom radios do not
>suffer from the same CAT problems as the FT-736R. Station will read the
>frequency from the radio dial, calculate Doppler, then set the
>corresponding frequency pair on the radio. Essentially you use the radio
>the same as HF, turn the dial, find someone to talk to, then talk
>letting the program do the rest. Station gives you the option of fixing
>the ground RX freq. or the ground TX freq. As currently implemented the
>FDT box is a lock. First you find someone to talk to, get calibrated,
>then hit the FDT lock. The moment you hit the lock, the program goes
>into FDT mode and fixes the transponder freqs, then varies both up and
>down ground freqs for Doppler.
>
>As I said before this is a technology demo, it was intended as proof of
>concept. In the Station 2 production version a way must be found to
>allow the tuning across the passband in FDT mode, that needs some more
>thinking about, but will be done.
>
>Now all the above is with the Icom (and Kenwood) radios, with the
>FT-736R and FT-847 (which is just as bad CAT wise as the FT-736R) I
>provide two tuning sliders, one for the passband, and the other for fine
>tune adjustment. These simply replace the calls to the radio dial. You
>use Fix RX or TX to find the freq. you want, then press FDT to lock. Its
>not as nice as the Icom solution, but its better than nothing.
>
>So to use Station with an FT-736R, here is the step by step guide.
>
>1). Make sure that the FDT box is not checked to begin with.
>
>2). Choose either Fix RX or Fix TX, I tend to use Fix RX.
>
>3). Find the slider that controls the passband frequency. The slider is
>calibrated to the passband, not the actual band. 
>
>4). Find a clear frequency on the transponder.
>
>5). Clear the "adjustment" value, the auto-Doppler should put you close.
>
>6). Use the adjustment slider and buttons to tune your link, you'll
>never get a 100% auto correction in practice. Station will remember this
>adjustment for next time.
>
>7). Once calibrated use the passband tuner to find a CQ call.
>
>8). Once you've found the CQ freq., then press FDT to lock the Station
>in. You may have to come out of FDT from time to time to re-adjust. This
>is the bit that needs improving in Station 2.
>
>I should point out that the Fix RX and Fix TX methods are  fully
>debugged (as is the SAREX/MIR mode as well). These have been working
>since 1994 and replace the old manual methods of either keeping the RX
>or TX fixed and varying the other by hand. Using these methods you will
>be better off than the old manual method on day one. FDT is a refinement
>of the process. FDT is only any good if the other end of the link is
>using FDT as well. If you are talking to someone without computer
>control then use the Fix RX or TX method. I look forward to the day the
>everyone is using FDT.
>
>Now the problems that you'll see on the air with auto-correction include
>the following:
>
>1). The calibration equations published do not always match those in
>real life. The RS-10 Mode A transponder was 4.8kHz off when I was using
>the bird.
>
>2). PLAN13 is good but will suffer if you use NORAD keps, which most
>people do. I guess that you guys either use SDP4 or smoothed keps from
>James.
>
>3). In most cases the op on the other end has no auto Doppler
>correction, and so you have to keep re-tuning to help him out. Hopefully
>this will change when we get the word out about how easy computer
>Doppler correction is in practice. This particularly bad on FO-20/29
>where the tendency is to leave the TX set and leave the RX to vary. This
>can cause some real big sweeps across the passband.
>
>In the tests I did on AO-13 Mode S, auto correction is very effective on
>the high bands on P3 type birds. Mode S operation was great, well until
>the alligators found it. The dish that I built to James's design works
>brilliantly, and I look forward to lots of use from it on P3D.
>
>I hope that explains where we are currently, ... as soon as P3D is up
>then I'm going to get the whole thing sorted out, my intention is to
>ditch my 2m KLM 22C as soon as possible (I live in a hurricane area, so
>small antennas are good), and move to the higher bands, ... FDT is going
>to be the enabling factor in this quest!
>
>Look forward to seeing you at Surrey, I'm down to run the pub quiz, so
>see you soon!
>
>I'm copying this message to the AMSAT-bb, as it may start some good
>discussion.
>
>Cheers
>Paul, VP9MU
>AMSAT-BDA
>
>P.S. the latest Station patches can always be found on the web site
>below.
>
>http://www.amsat.bm
>
>
>-----Original Message-----
>From: Graham Ratcliff [mailto:gratclif@senet.com.au]
>Sent: Monday, June 08, 1998 6:51 AM
>To: vp9mu@amsat.org
>Cc: jeff@kcbbs.gen.nz; Jeff.Garrett@airnz.co.nz
>Subject: Full Duplex Mode in Station Program
>
>
>Hi Paul,
>
>First, let me congratulate you on your an excellent program called
>'Station' and the professional manual that you and Todd, K1TM have
>provided
>- well done!!!
>
>As you are probably aware Jeff ZL1BIV has been providing me with
>registration numbers for AMSAT-Australia newsletter subscribers who have
>donated $20 to AMSAT-Australia. Some time ago Jeff also provided me with
>a
>registration number but until recently I have not been using your
>software
>because most of my activity of operation of late has been on the 9600
>baud
>digital satellites for which I use Chris G7UPN's WiSP software in
>conjunction with SatTrak4 for automatic antennna and doppler control.
>
>However, I am presenting a paper at the AMSAT-UK Colloquium next month
>entitled 'Automatic doppler correction for analogue transponders' which
>has
>prompted me to take a serious look at your 'Station' software.
>
>The purpose of the paper is to encourage analogue transponders users to
>consider using full duplex automatic doppler correction - by that I mean
>maintaining a fixed RX/TX transponder point at the satellite. I have
>programmed such a mode into both the SatTrak3 and SatTrak4 firmware but
>if
>I am going to be successful in convincing more users to try this mode
>there
>needs to be a way to implement it without having to use a 'special' box
>preferably using a standard PC which most have in their shacks already
>runing some tracking software.
>
>So far I have identified FODTrack by Manfred XQ2FO and your 'Station'
>program as possible candidates. So, today I have spent most of the day
>'learning' how to drive 'Station'. However, when I try to use your full
>duplex (FDT) mode on FO-29's transponder I am having a little difficulty
>understanding how you intended it to be used. Therefore, I was wondering
>if
>you could give me a little bit of guidance in this area?
>
>I am runing version 1.0l Beta 20 and have setup the full duplex mode on
>FO-29 as described on page 32 of your manual. I am using the FT736R
>radio
>and the RS232 link between 'Station' and the FT736R is functioning
>perfectly.
>
>What I am trying to achieve using 'Station' is the same as I do using
>the
>SatTrak4 (ST4). In the case of the ST4 I have calibrated FO-29's
>transponders and know that the translation frequency using my FT736R is
>581.80192MHz. I am also assuming that the station in the example below
>is
>also running full duplex automatic doppler tuning on the uplink and
>downlink to maintain a fixed point on the transponder.
>
>1. I hear a station calling CQ on 435.8788MHz.
>
>2. I input this RX frequency into the ST4 (because as you know the the
>FT736R does allow you to read back the displayed frequency way via the
>CAT).
>
>3. The ST4 corrects this frequency for doppler and calculates the
>corresponding point on FO-29's transponder i.e. the frequency on which
>FO-29 is transmitting.
>
>4. The ST4 then subtracts that frequency from 581.80192MHz to calculate
>the
>frequency on which FO-29's transponder expects to hear an uplink from
>the
>ground.
>
>5. The ST4 then doppler corrects that frequency and then updates the TX
>frequency on the FT736R such that when you transmits on that frequency
>the
>downlink comes down on 'exactly' 435.8788 MHz or very close - hi!!! 
>
>6. In practice, by the time I have completed step 2. and the ST4 is in
>control the desired RX frequency may have changed slightly so I have the
>ability to change the  RX frequency (which is actually the transponder
>point frequency) slightly (selectable 10 or 100Hz steps) via an up or
>down
>button on the ST4's front panel. 
>
>I hope all the above makes sense and that you can explain to me in a
>similar fashion how you use 'Station's' FDT mode to achieve the same
>goal???
>
>Any help or suggestions on this topic would be most appreciated......
>
>73 Graham VK5AGR
>
>
Email: wricharz@charlotte.infi.net
alternate: n4dh@juno.com
AMSAT-NA # 32372        



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