Okay, first off, SatPC32 and other computer control software has done this exact thing for years. And it has effectively done it without sending garbage signals. There is also FlexTune which sends a tone to initially calibrate, then the rest of the Doppler corrections are done mathematically vs continuously sending garbage. Another thing of note, you're already sending your voice, why add more? The other software is initially calibrated manually then continues track with that offset automatically. Seems better than loading a transponder with even more nonsense.
Personally, I don't see why people consider the linear transponders to me so mystical. They're simple: signal goes in one point, out the other. Big whoop. To tune just use a little bit of basic math skills that a 2nd grader should possess and then turn the knobs till the voices sound right. Pretty easy, right? Instead we have people who I've never heard on any satellite (in my two years and 10,000 sat QSOs) suggesting complex and unnecessary things to make operating on these satellites "easier", when most competent ops already find them plenty easy.
73, Gabe AL6D/actuallyoperateslinearsats
On Fri, Apr 13, 2018 at 7:53 PM, Eric Fort < eric.fort.listmail@fortconsulting.org> wrote:
Computer control or actually a variation of such *IS* what I’m considering and proposing. Yes I have read “the one true way”. I understand this manual tweaking is how it’s currently done. Why however are we adjusting only one frequency? It seems that we can adjust the transmit frequency so that it is always the same distance from the beacon as seen by the satellite and the receiver can automatically track the subduable tone transmitted. This means that you need not drift across the transponder and the rx station automatically tracks. What am I missing in this being hands off and always on frequency?
AF6EP
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On Apr 13, 2018, at 7:49 PM, Andy w5acm@swbell.net wrote:
So VERY true! Thanks Bruce, ANDY w5acm
-----Original Message----- From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Bruce Sent: Friday, April 13, 2018 9:40 PM To: amsat-bb@amsat.org Subject: Re: [amsat-bb] Making the transponder sats as easy as the fm
birds
Sorry, this theory of thought is incorrect. You must adjust the higher
of the two frequencies as it is most affected by Doppler. The true way to adjust is really to adjust both frequencies, however in the absence of computer control of both frequencies, you adjust the higher. Thus, if it is the receive frequency, then you adjust the receive, if it is the transmit, then you adjust the transmit. Holding the transmit frequency on the wrong band will cause you to walk across all the other QSO's taking place which is not a good practice.
73...bruce
On 4/13/2018 8:41 PM, Eric Fort wrote: I’ve had an idea for a long time as to making the satellites with
linear transponders as easy to use as the FM “easy sats “. Consider the following:
As I understand it, the goal is to adjust your transmitter such that
your frequency at the satellite is constant.
Our tracking program gives us range to the satellite and its velocity
relative to us given our location and the orbital parameters. From this we should have computed Doppler for both transmit and receive.
We also know the frequency at the satellite of the various beacons onboard. From this we can measure the doppler and work the other direction
If we transmit a subaudable tone of known frequency we should be able to adjust the rx automatically by tracking the tone. (Acssb)
Given these multiple ways of setting our tx/rx frequencies for our
location can this not simply be automated to such a degree as to simply specify an offset from the beacon and operate as if it were a regular predictable opening on hf?
Af6ep
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