Other SOTA sites: SOTAwatch | SOTA Home | Database | Video | Photos | Shop | Mapping | FAQs | Facebook | Contact SOTA

Datamode - FT8


Hi Barry,

Ooops. My apologies.

You can exceed 13 characters, but not quite as I typed. Sorry my brain increasingly has disconnects and I make mistakes I don’t notice. What I should have typed, which is different is


I’ m sure I posted this and some other suggestions before along with the acknowledgement that the average bear might also get confused if they have not heard of SOTA. And there are a lot of very average bears on FT8.

If you want to see what you can send, type the text in message 5. You have to shut the rig down and let the program transmit so you can see what is viable - the TX text will show in the RX window if the right boxes are ticked…

The FT8 program has shorthand methods of sending some elements such as 73, hence you can send VK3ZLP VK3AFW RR73, which is 18 characters, as a routine thing. Having a fixed format is also helpful for minimal coding but does impose some restrictions.

I’ve yet to figure out how to send my call and the SOTA Ref in the same message.

Unfortunately no response to my request for replacing the Grid Square in some transmissions with XOTA where X can be S, J, I, L, all common activities where FT8 would be useful.

Maybe it’s too hard or considered plain silly.



Will that work? It’s over 13 characters and I don’t think it will be able to encode that as a callsign.


13 characters is the limit for free text. Normal transmissions exceed 13 characters as a matter of course. See example below.

Don’t take my word for it, it’s all explained in the manual.:grinning:

If it sends it it decodes it.

All explained in the manual.:grinning:

Same place covers callsigns and prefixes and suffixes and the limits of the inbuilt logger.:astonished:



I understand how it encodes callsigns and so can exceed the 13 character limit. Reading the manual suggested to me that it couldn’t work, but indeed it does. However, it doesn’t allow SOTA/G4TGJ/P - that has to be encoded as free text with a 13 character limit.


There isn’t a single FT-8 alert (or JT-65 for that matter) in the list. Anyone?


Correct, A 4 character prefix is acceptable.

Your country might come up as “where?” in the comments section but otherwise it is decoded as sent.

A reasonable assumption is that a station calling CQ SOTA is portable so the /P is redundant. I understand some prescriptive regulators might not like that so you would have to figure out what works for both of you.

The SOTA Reference has to be consigned to free text in message 5. Well that’s as far as I can tell and what I’ve done.



Was someone activating using FT8 on or about Nov 12 12:20 UTC? A spot was attempted (but the PSK features are still inert) and I’m trying to work out who that might have been (need better logging :smiley: )


I am hoping to do an FT8 activation tomorrow from W2/EH-001. Not sure if RBNHole is monitoring digi yet, but this might be a chance to find out.

My biggest challenge is getting the portable time sync working consistently using TomTom bluetooth GPS receiver and BktTimeSync software so that WSJT-X is synchronized. I also discovered that the KX2 heat dissipation characteristics make it a questionable digi-mode radio. The KX3 is slightly better in this regard and I suspect the Yaesu 817 is better than both. So going for the lighter weight radio isn’t always the best decision.

I’m planning on just using standard FT8 messaging format and frequency. I have no idea if there are really many (any?) FT8 chasers out there.

73, Barry N1EU


To my mind this seems to be the reverse of what should be expected Barry. I would have thought that the KX2 and KX3 would have a greater frequency stability than a mass-produced rig like the FT-817. The 817 gets quite warm in operation and I would expect this to affect the stability. I guess that you will have to suck it and see.

BTW, accepting that the conditions in the shack are nothing like out on a summit, it is surprising what rigs can be used for digimodes - my main digi rig is a 34 year old Trio TS-130V which is surprisingly stable after the initial warm up period.

I see you have alerted for 14:00z tomorrow, so I will have a listen when I return from leading a local walking group. The antenna is only a Windom, but it gets a signal across the pond okay. Might be worth putting up the vertical.

73, Gerald G4OIG … (note to self - switch on rig before going out. :wink: )


I wasn’t thinking in terms of frequency stability (non-critical for FT8 mode) Gerald but in terms of how hot the final transistors get. The KX2 and KX3 provide the ability to monitor PA temperatures and at normal room temperature, I saw the KX2 finals exceed 60 deg C after several FT8 qso’s at 5W into low SWR. This was surprising. The heat built up slowly but clearly heat can’t escape in the KX2 between xmsns. My favorable comments on the FT-817 were with respect to it’s ample supply of cast aluminum.

Barry N1EU


Yes, that’s a very valid point. The 817 does warm the backpack quite well, but as you say it has some mass. That’s what is nice about the 130V - it will run key down 24/7. No need to restrict it for datamodes. I read somewhere the PA is capable of 30w out, whereas it is throttled back to 10w out. It reminds me of my old Audi A6 2.6 V6 - a large engine that was controlled to produce just 150BHP.


Monitoring, but not posting yet. Will try keep an eye on it in between family holidays ie, when my wife is not around :wink:


We’re going to try to activate W7U/GR012 tomorrow morning; first activation for this 6 point summit. I want to try FT8, but haven’t come across any consensus about the proper use of the abbreviated dialogs.

CQ ?? K0GUZ DM59 : Should I use SO, ZZ or nothing to indicate that this is a SOTA activation?

And the final free form data field, is this appropriate?

73 W7U/GR012



Steve, my take is to avoid any special messages for the time being, but that’s up to you. What are you using for a time sync for portable FT8?

I’m afraid I’m probably going to abort my FT8 activation tomorrow because I find myself once again in bluetooth time sync hell. I will spare you all the details.

73, Barry N1EU


I have read back up the thread and I don’;t think anyone has suggested omitting the maidenhead reference. Apologies if they have, but I think it is a bit spurious on HF anyway. Who really cares whether I am in IO92 or another English square? So in the CQ frame I would send CQ G4OIG SOTA and not CQ G4OIG IO92. SOTA implies /P as has been said…

The reference of the summit in lieu of the RRR 73 is a good idea. If a callsign doesn’t fit why not just identify with the suffix in the call? So I might send G/CE-004 OIG. I am sure something similar was used on high speed CW MS some years ago with the rogers as by that stage both calls had been copied anyway.

Sorry to hear of the time sync issue. Can’t say that I have ever had to worry about that. Certainly for JT-65 it has been sufficient to sync before leaving home.

73, Gerald G4OIG


Right now, only 6m gird chasers care. As of Jan 1, everybody involved in the ARRL International Grid Chase will want a Maidenhead grid ID.





There is no consensus. I suggest you figure out what you want to TX and try it on the computer with the rig off. You will see in the right side window what was transmitted. When happy, use that.

Good Luck


Thanks. Look for me tomorrow about 1730 on 17, 20 and 30

73’s de K0GUZ


A post was merged into an existing topic: Datamode - FT8 Part 2


This topic was automatically closed after reaching the maximum limit of 100 replies.