Icom IC9700 doppler control

Hello all,

I am trying to run my IC9700 with gpredict and hamlib-w64-4.0 which now has a beta driver for the 9700.

I am able to make gpredict work with the m- 381 switch which is the IC9700 but the frequency update is not working properly.

Now I am not sure if it is related to gpredict or the hamlib driver because other software like satepc32 do work properly with the IC9700.

What is going on is that both VFOs are constantly being swapped Main/Sub to Sub/Main then back to Main/Sub on top of the SPLIT function that always turn on on the radio.

The proper way would be instead to select the Main VFO (uplink), push the frequency update then select the Sub VFO (downlink), push the frequency update and then return to the main VFO until the next frequency update pushed by gpredict.

I did try the IC910 driver with the proper IC9700 CIV adress and it does the same behavior, both VFOs constantly swap along with the SPLIT function that turn on.

Any ways to fix this issue ?

Thank you all !

Pretty sure this is a known issue (i.e. same behaviour with the IC-910H / IC-9100), and is mainly still present because Alex doesn’t have a radio to test with (and I’m not sure hamlib exposes the VFOs correctly).

Any way we can help ? Sending information from hamlib or something else ?

To be honest, I think these days the lack of time and priorities is the most critical factor.


To whom be interested, I posted the trace log of hamlib along with a video showing how the IC9700 react HERE.

Thank you all !


I ran into this problem a year ago when I first bought my IC-9100. I agree Gpredict is the best FREE tracking software available. I understand
a) the author is a busy man with work and other activities, and
b) he does not have access to an IC-9100 for testing.
In my opinion, the IC-9100 is not sensitive enough for satellite work without an outboard LNA for the receiver.
I have overcome this problem by using a SDRPlay receiver with LNA and homemade QFH antenna.
I use the IC-9100 for transmit only with a separate QFH antenna. Gpredict controls Doppler on the Receiver and I manually control the Transmitter.
“There are more ways than one to skin a cat” as we say down under.
We also say “Don’t look a gift horse in the mouth” referring to the fact that this software is free.
There is no point in complaining. The author is busy and we thank him for his contribution.
Cheers Bob vk2byf

1 Like

@vk2byf so this confirms that the IC9100 ALSO suffer from this behavior.

My point was to help since I DO have a 9700, gpredict and hamlib installed on windows (unfortunately) so I can provide logs and whatever the community would ask. I sent what I could at the moment and I’ll see how it goes from there.

I am NOT complaining about anything. Am I disapointed ? yes, about the lack of available programmers who could handle those issues with gpredict and I am also disapointed about the lack of interest for this beautiful program…

like I already said, gpredict is the most beautiful, efficient and well crafted free or not software. All windows software, including paid ones (besides maybe HRD that is more recent but does not support the 9700), for satellite tracking are outdated, often back to the 1990-2000s, clunky ugly interface… I think I’ve never swear that much at a software, satpc32 not to name it, but it seem to be the only one that support the IC9700, rather a little bit wobbly but it works, along with antenna positioning. I don’t understand why the community support that old interface… but that is my opnion…

@csete was kind enough to justify his position and I respect that. I can’t force anything, it is a free, open source software, he has no obligation to support but at least he took the time from his busy skedule to confirm that gpredict project is still alive and that it is still possible to submit issues and suggestions.

gpredict is soooooo close to be a fully functional software with the most recent radios… If I only knew how to program, I would gladly jump in but for now, the only thing I can do is send as much information as I can about the issue.

You have an IC9100, I have the 9700, we can both contribute to the free project. That is what I did.


I love Gpredict, There is nothing like it. I’m about a year ahead of you making the same offer to help but I too will never be a programmer. I tried to learn GNU radio. I tried to learn Python and even Arduino which I started to actually enjoy. Similar to GBasic in the 70s? It all looks like Chinese to me. I can barely manage hamlib. I think to be a programmer you have to have at least one extra chromosome. Programmers are definitely a different breed and I have a lot of respect for them. We will either have to learn how to fix it ourselves or be patient.
73 Bob vk2byf


Not sure how IC-9700 differs to IC-910H. But I’ve got my IC910H working with gpredict 2.2.1 without any issue at all using fork from a github user named arodland. Worth to look at that!

I checked here https://github.com/arodland but I couldn’t find it.

what settings are you using ? full duplex ?

Here it is: https://github.com/arodland/gpredict/tree/ic-910-hack

You should be able to build this from source (assuming you have some knowledge how to).

Here’s a tweet after I successful got it to work flawlessly on my raspberry pi 3b+. Note: that rpi which has the gpredict is now already inside my radio, wrapped with aluminum to minimize interference, so if I carry my radio, I’m also carry sort of computer… https://twitter.com/DV2JB/status/1141422243911573504?s=20

Gpredict without that “hack” would just back and forth interchange the vfo of your radio which is definitely a bug.


that is nice to see it work properly on your 910, specially on that raspberry pi !

unfortunately, I wouln’t know how to compile that 910 hack… I am not a programmer… the only thing I have is the equipement and I already sent a capture of the data exchange between hamlib and the 9700 with a video on what is going on.

But it’s nice to see there is a hack available. I just need to figure out how to compile that code…

by the way, I don’t think the gpredict version has something to do with it since you were talking about the hack. If you run the latest version of gpredict, does it still work ?

If the newest version does not work even with the hack, we might have something else on our hands in the latest release of gpredict to correct.

The hack was put together from the original repo, the author (alex) is aware about this issue that latest gpredict wont work with your radio and even with my ic910 without the hack.

Not sure how could I further help you, if you have no idea how to build gpredict from source.

ah ! ok, so the hack only work on that older version of gpredict. I can’t compile, don’t know how plus I’m on windows os. But thank you for sharing this. Good work by the way on your system.

No, the ic-910 hack is merely an edited version of the latest repo in github. If you want to enjoy and learn more about gpredict overall, go away with windows. Gpredict was entirely made for linux and alike, alex has no intention of supporting windows as far as I could tell.

I think this could be turned into a proper PR for the original project. Has someone of you been in co tact with the Author?

I understand that gpreidct is mainly a linux program but there is one important thing to remember is that not everybody know how to use linux and a high % of ham radio programs are made for windows so I won’t move away from windows.

Gpredict port to windows is beautiful, works well and is the most efficient windows program for ham radio satellite tracking. I sure do hope I am not wrong about that…

And there is another important thing, if this community feel it is NOT important to support gpredict port to windows, I’ll move away then, there is no need for my help.

Windows NEED a ham radio satellite program and gpredict is THE modern solution at the moment. Don’t tell me to move away from windows… If this community is not interested in supporting windows, first I think a big part of the satellite enthusiats won’t be able to benifit from that superb gpredict program and secondly, I’m out of here. What is the purpose of this then ?

I am the initial poster of this very own thread, I want to help to the best of my knowledge and I think some other people in here are willing to take over where I can’t even though I am NOT a linux user, because at the final point, I would expect that gpredict WILL be ported to windows.

You see this here ? There is a reason for that to happend…

Interesting, I was where you are a year or so ago.
I use Linux Mint and it looks and feels like Windows but it works and you are in control not Microsoft.

Windows should be called Wait dows. How do people put up with not even being able to even shut down because Microsoft wants to fix it’s OS?

Everything I do, as far as HAM radio is concerned, I do in Linux with the one exception SDRuno. It is Windows only or Linux with CubicSDR. I don’t like the Cubic UI. I admit you have to work a little harder to find software for HAM radio but it’s there, you just have to make the effort to find it.

Once you get used to Linux you will never go back to Windows.
Linux catch phrase should be “It just works”

I’m 70. My wife and her 80+ year old father use Linux Mint and they taught themselves. They love it and would never go back to Windows.

By the way I installed Gpredict on my Windows7/Linux laptop and it works just fine. First time.

I agree Gpredict is a very good program but now I don’t have to fiddle with Orbitron anymore which served me well until I saw the Light.

I have never made or needed a backup and I don’t need antivirus protection. No one could be bothered writing malware for <10% of the PC users. I suspect the people who sell the protection are the same people who write the viruses.

Linux is not for everyone.

I am NOT a programmer, I’m strictly hardware I just learn what I need to know to get the job done and I’m not afraid to learn new things.