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Re: [linrad] Frequency control

Hi, Leif!

Thanks for this excellent email. I apologize for not answering it. I had a major disagreement with Microsoft Outlook XP and I scrapped it in favor of Netscape Mail and temporariliy lost this and a couple of other emails in the transititon.

I am working on the code for the transmitter control but don't have anything working yet. I am first doing it as a module outside of Linrad. If I get that working I will come to you with more questions.

I have started to think however about what might be good information for Linrad to send/receive via the serial port. THe way I see it all of this would be sent out the serial port and it would be up to a program at the other end of the serial port to decode the information and send it to the appropriate hardware.

1. The frequency of the received signal in the high resolution window as first centered. I would think that maybe this should be set up so that one clicks on the received frequency in the high resolution window to center it and then types "L" or something to lock the transmitter frequency so it doesn't change after that if the signal drifts, or if Linrad locks on the transmitted signal when I am transmitting,, etc. To unlock it you could type "K" or something. After "L" had been typed the frequency sent out of the serial port would not change until "K" was typed and the signal again clicked and "L" again typed. Does this sound like the way to do it? Also this way you could play with the transmitted signal frequency by clicking higher or lower on the high res spectrum and then locking things in with "L", and then clicking again where you wanted to listen. Since the transmit signal was locked in, this would not disturb the transmit frequency setting.

2. One could correct for Doppler perhaps by saying if one wanted Doppler correction one would type "D" instead of "L". Then the Doppler correction at that time for the station entered in the EME window would be applied to the signal and locked in. The transmit signal would not follow the changing Doppler.

3. Should there be some way of setting in the prefix for the transmitted frequency? e.g. 144.0, or should this be left to the external program?

You have addressed these things with this:

1) Currently selected tx frequency (could be entered manually)
2) A button to set current RX frequency to the new tx frequency

To me it seems like it should be the other way? Place transmitter in relation to the received freq?

3) Currently selected offset (RIT control)


4) A button to select current BFO frequency rather than the passband center.

With Linrad display which shows the carrier frequency don't we want transmitter to be right on carrier frequency, neglecting Doppler?

5) Enable/disable EME doppler shift offset.


And some vertical line to show us where the transmitter is, on the high resolution display.

It is a good idea to place the open routine in hwaredriver.c as you did.
I will add a dummy routine in the next Linrad version so you will
not have to change any other routine than hwaredriver.c

The open routine has to be called from somewhere else.
I think the best would be to call it from main.c and leave
the device open all the time Linrad is running.

Don't worry about doing this now, I know you are very busy, I am just getting my thoughts on pater for you before I forget them. Operating the EME contest made me more sure of what I needed to easily QSY.



PS the 'final' version of the article for your correction is coming later today or tomorrow. This is our "Thanksgiving Holiday" weekend and Thurs-Sun I have family here from all over the East Coast of USA and we have family activities that are taking me out of house and away from computers. This afternoon bowling with siblings and their and my children, this evening big gathering at Chinese Restaurant, tomorrow ?? ;) I am putting on extra pounds very quickly this week...food, food, food, no exercise...