Any VarAC Users?

I’ve just managed to complete my first QSO using VarAC on 20m. VarAC is a chat system which could potentially be used for SOTA. Because you (in a sense) speak to someone it is more personal than the virtually automatic QSOs using other digital modes like FT8.

I’ve installed it on my MS Surface tablet but today I was using my IC-7300 in the shack. A screen shot of the end of the QSO with EA3IGY is shown below. I plan to try it from a summit at some point and hopefully should be able to complete a QSO.

The RSGB published a video on VarAC, it starts at 29.40, before that it covers other chat modes.

The VarAC window. The QSO is at the bottom of the text, the lines above that with times are “beacons” which are stations saying they are on the air but they are not calling CQ. The system periodically reports these and they filled the screen so the start of the QSO has disappeared.


I’ve heard of that. Isn’t the software pricey? Not that I mind paying, but most hams want everything for nothing. :smile:


The VarAC software is free. You also need to install the VARA HF modem software which you can use free with limitations although these limitations do not prevent it working with VarAC.

The catch is a window keeps popping up asking you to pay $69 but you can click on the “Continue to evaluate” button and it disappears for a while. :slight_smile:


Hi John, thank for your video but I prefer psk31 and ft8. Not particularly interested in any of the others. Would like to see psk31 in more use though.

Geoff vk3sq


I use it. I also have a very small tablet for my SOTA activations and may give it a try. I paid for the full bandwidth VARA HF modem. I am thinking of putting a full time station on just for VarAC

Kent K9EZ

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Just downloaded the software and testing it. Still a lot to learn … here are two videos about VarAC for the german speaking users:

73 Martin, OE5REO


Hi Martin - wow, that’s a lot to take in at one sitting! Thanks for posting the videos here, very helpful, and I really like Arthur’s videos.

OK, so I’m intrigued by VarAC and I think I’ll give it a go. I have to say I’m not a fan of FT8, which I find much too hectic, and much preferred to use PSK back in its’ heyday, but not too many people are using it nowadays. And what ever happened to the Olivia mode, great for relaxed chatting, which I also enjoyed using for a while?

These low-power data-based modes appeal to me, since I nowadays only have a small multiband vertical (Komunica HF-Pro-2 Plus-T) which I can erect on the balcony rail when it’s dark outside (so nobody can see it!), and 10W output is about right. Of course this antenna is also great for SOTA activations!



I have tried it this morning using my SOTA equipment of IC-705 and MS Surface Go 2 tablet. With just 10W from my garden I managed a QSO into Germany.

A problem I can see using this on a summit was the QSO involved a lot of typing.

VarAC has the ability to store “canned” messages and I need to look at these as it might be possible to complete the QSO just by selecting these messages although this will potentially make it a bit like FT8 if I am not careful. Keeping the human element is important. :slight_smile:


I managed to install VARA and VarAC today and - despite one or the other website telling me their software probably will not run in Windows 7 which I have installed on the 15-year old laptop I still use for digital modes - both appear to be running OK. At the moment, I’m just testing the setup and transmitting into a dummy load; a couple of stations running as beacons have nonetheless been received through the dummy load!

One thing I’ve not managed to do is to get pskreporter to show anything at all - it’s effectively dead (tested on another m/c). Will make a first CQ call this evening.


I would like to use PSK31 but I can never get FLDIGI set up so it decodes properly, I just get rubbish!



I’m not sure why pskreporter isn’t showing anything although I have heard reports it has been struggling recently as it has reached capacity at times due to the number of hits it gets, almost all of which is FT8. In the bottom left hand corner of the psk page is a link to statistics which is worth having a look at to see just how much traffic it handles.

I tried VarAC from a SOTA summit today but without success. I’ve written a short report here:

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Yes, that’s what I had imagined.

As regards my trials this evening, I have to say that neither VarAC nor WSJT-X can be made to work properly here (they start up, appear to work perfectly, but something just ain’t right), although WSJT-X had been running perfectly well earlier in the year. What’s changed? - well, the laptop received multiple updates yesterday to its’ Win7 OS - the first time in several years - after not having been used in the last few months. I fear the OS has been so much “improved” that these programs are having difficulty running - will try again tomorrow.


So, I’ve done some extensive tests today and have definitely come to the conclusion that, as the page suggests

[runs on] Windows 8.1 and above (some hams reported that Win7 also works. but officially it’s not supported)

the VarAC software just doesn’t run well under Win7 - it freezes up, and also hangs other processes upon which it depends.

So, I’ve uninstalled the VARA and VarAC software and there’s one less (potential) VarAC user on the air. I hope others have better results.


Disappointing, but many thanks for giving it a try. :slight_smile:

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Perhaps this is just me, but I have a bad feeling about the use of proprietary, closed source modulation schemes in amateur radio. Its possible I’ve missed it, but having a look over a few of the documents and presentations on the VARA HF website I can see some top level descriptions of the OFDM scheme used but there doesn’t appear to be a specification of the symbol filtering, bit interleaving, encoding, puncturing etc that I would expect to find that would allow reproduction of this modulation scheme.

I have no problem at all with there being a commercial implementation of any digital modem, but I do think there should be an open, royalty free, published standard for any modulation scheme used within amateur radio.

73 Jonathan



Before someone mentions D-Star and AMBE codecs et al. Everything you need to produce your own AMBE software implementation is in the AMBE patent docs. They’ve expired now as well. Likewise for C4FM/DMR the AMBE2 patent gives all you need to implement your own encode/decode. Its patent is still valid so no producing the software and giving it away :slight_smile: But everything you need is available should you have the skill set to do this.

Not so with Vara. Just saying…

As for running new code on old OS. After a while as updates march on and on, trying to do this is as effective as King Cnut’s attempts to command the tide to stop coming in. It’s just not worth the effort when you can install Win10 in a free VM system like VirtualBox. Any relatively recent “Post Noah’s Ark” AMD64/x86_64 CPU will have the virtualisation hardware. Win10 runs admirably on VirtualBox either Win10 VM on Windows or Win10VM on Linux. If you have a Win7 licence you can still install Win10 and activate it with your Win7 licence for free too.


So, I’ve got my Win10 laptop set up now to do various digital modes (and set the older Win7 laptop to one side), and needed to buy a little Y-splitter for the headset output. I’ve now got WSJT-X set up to do FT8 and other modes, and tested WSPR this morning. Got VARA/VarAC set up and working yesterday evening, but have yet make any VarAC QSOs. Also had to wrap the USB cable from the microHam unit to the laptop some 15 times around a large FT 240-77 ferrite - thanks to Ed @DD5LP for the tip.

Looks like I’ll be ready to try this mode out, but I doubt I’ll lay out the $69 or so for the VARA software modem used by VarAC, which seems very steep to pay for something which will be used in such limited circumstances. How can the developer EA5HVK demand so much? That’s the same price one would shell out for the much more powerful Ham Radio Deluxe which, it has to be said, has lost a lot of relevance these days. If I really wanted to pursue this mode, I’d maybe be prepared to pay $15 but not much more…


The $69 is for VARA which is the software modem VarAC uses. VarAC is the free program where you enter your text into but it then communicates using VARA which is a commercial bit of software made by another organisation.

But I can’t see me spending $69 either! Having tried it from a SOTA summit I’m not sure it is very practical as it is slow and you spend a long time waiting for someone to reply. This is not fun on a cold summit!


Yes - and according to PSKReporter, there don’t seem to be many using VarAC at all. Still, it’s always a useful exercise in station (and old brain-cells) management to try such modes/software out. I’ll try some VarAC QSOs this evening…


The latest (December 2022) Practical Wireless has an article about VarAC.