I've started designing a simple Java application that will run on a Nextel phone (should actually run on any java phone) that will automate the frequency shifting necessary to have a QSO on a Linear/transponder satellite.
I know that I'm nowhere near as experienced as most of the guys on here, so I wanted to run a few things by you, so you can tell me if it is a good idea, or how it might be improved.
In the first Phase, the application will use an internet connection to connect to a running Predict server (that's the Linux satellite tracker program). The application that runs on the phone will interface to predict to obtain Doppler shift information about the satellite currently selected, based on the QTH coordinates programmed into Predict.
As the satellite approaches and then departs, the application on the phone will, via an ICOM CI-V interface, shift the frequency such that the operator doesn't have to touch the dial (once its set where he wants it).
In order to be most useful, I'm thinking that the operator should scan around on the RX frequency and find a spot, whether it's an open frequency for calling CQ, or a frequency where someone else is calling CQ and they want to respond.
By selecting that RX frequency, the application will make calculations and properly adjust the receiver such that the correct input frequency is used. In effect, the application will pair up the correct TX and RX frequencies so that you transmit on the input frequency that corresponds to the output frequency, with Doppler, and everything else factored in.
That was sort of question 1 there, is that how it ought to work?
Then the next part of the question would be: Should the application leave the RX frequency constant, not adjusting it whatsoever for any Doppler, etc, and only adjust the input frequency?
Hi Brad,
I operated mobile using a half-duplex radio and a cheap 386 PC to control the radio some time ago and it worked fine so this should work. I used InstantTrack for the orbit calculations and an application I wrote called "InstantTune" to control the radio.
You can get InstantTune and all the source code (C++) from the AMSAT software archives. It will run CI-V radios as well as almost any other type of radio. Please feel free to use whatever you can. It was designed with UNIX in mind (even though it runs under DOS) and it should not be hard to make it run under Linux.
I wrote a paper on the idea for the 1997 AMSAT Space Symposium, "An Object-Oriented Approach to Automatic Radio Tuning."
Best of luck with your project. If you want to ask me any questions, please feel free to email me directly.
73, Tony AA2YX ---
At 05:07 PM 10/19/2006, Brad, K1GTo wrote:
I've started designing a simple Java application that will run on a Nextel phone (should actually run on any java phone) that will automate the frequency shifting necessary to have a QSO on a Linear/transponder satellite.
I know that I'm nowhere near as experienced as most of the guys on here, so I wanted to run a few things by you, so you can tell me if it is a good idea, or how it might be improved.
In the first Phase, the application will use an internet connection to connect to a running Predict server (that's the Linux satellite tracker program). The application that runs on the phone will interface to predict to obtain Doppler shift information about the satellite currently selected, based on the QTH coordinates programmed into Predict.
As the satellite approaches and then departs, the application on the phone will, via an ICOM CI-V interface, shift the frequency such that the operator doesn't have to touch the dial (once its set where he wants it).
In order to be most useful, I'm thinking that the operator should scan around on the RX frequency and find a spot, whether it's an open frequency for calling CQ, or a frequency where someone else is calling CQ and they want to respond.
By selecting that RX frequency, the application will make calculations and properly adjust the receiver such that the correct input frequency is used. In effect, the application will pair up the correct TX and RX frequencies so that you transmit on the input frequency that corresponds to the output frequency, with Doppler, and everything else factored in.
That was sort of question 1 there, is that how it ought to work?
Then the next part of the question would be: Should the application leave the RX frequency constant, not adjusting it whatsoever for any Doppler, etc, and only adjust the input frequency?
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participants (2)
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Anthony Monteiro -
Brad, K1GTo