I would be very interested in SOTA/FT8 enthusiasts perspective.
so I have been having a bit of a play with SOTA and FT8…see set up below. It seemed to me (being a low power signal mode) to be a perfect match. Typically I do 10-20 QSO’s on 20/40m SSB with 5-6w on my FT818ND and then switch over to FT8, where I would expect to do better.
On recieve I get a huge amount of decodes, noticeably more than at my home QTH, however on TX it seems to be much much harder to get other stations to recieve. Has anyone else had this problem?
It got me to wondering why this might be, and I thought that maybe it because the recieve S/N is many many times better on the mountain away from QRN? Would using/spotting a frequency other than the normal FT8 frequencies help? It should in theory improve the chasers S/N through reduces QRM?
It’s a dilemma. You want some space to operate, but you also want to be found by other stations that might not be specifically SOTA chasers.
On most bands (80, 40, 30, 15, 6, 2) I find using the standard FT8 frequency is best. On 20, I usually use 14.074 - again, the standard frequency, but if there is likely to be potential S2S SOTA activity, we tend to use 14.092.
Hi John,
All of Joe Taylors modes are designed for low signal level reception however that does not have to equate to low power transmissions. A lot of people run fairly high power FT8 stations from their home stations which may well explain the imbalance you see on a summit - lots of stations there but none of them hear you (or at least don’t come back to your call). (aka the “crocodile effect” big mouths, small ears - the same as we often find on SSB).
Not really - simply because I have never operated FT8 from home, or in fact from any kind of “shack”. I have only ever done FT8 from a summit.
I have found it quite challenging to get working properly in a SOTA situation - lots of patience and determination required. So that might be different, as there have been several “armchair theorists” on here that have professed that FT8 SOTA would be very easy - but have yet to undertake a successful FT8 SOTA activation!
With regard to actual on-air success, I’m not sure. There will be the disadvantage of low-power, and a less-than-optimum-spec cheap tablet (as opposed to a new high-power hi-spec fast PC/laptop). But there will also be the advantages of a low noise floor, and a distant horizon - especially beneficial if using a vertical-with-groundplane antenna.
I’ve worked the world with FT8, using an FT-817 running 5w. Mind you, I’ve also done that with CW and SSB. I’ve definitely found it much easier to make HF SSB/CW contacts, including DX, with 5w from a summit than I have with 100w from home. So I would imagine it would be the same situation with FT8.
Yeah it takes quiet a bit of patience to get working. Just did a test at the home qth with my SOTA set up on FT8 and contacts were much less of a problem, operation almost identical to my shack set up.
Low noise floor and distant horizon I get, I decode a noticeably larger number of stations when out on the mountain, it just seem relatively much harder for them to decode me.
Oh well the adventure and experiments will continue!
The main 40m (7.074) and 20, (14.074) frequencies can be quite hard to be decoded by other stations on when using QRP from a summit. I get significantly more success on 30m. I also find 80m quite good.
Another thought John - how are you keeping the time accurate when you are on a summit? At home, I’m guessing you are doing it via an Internet time service. Does your tablet have reliable Internet connectivity on the summit or are you hoping the internal clock within the tablet is stable enough and still accurate from the last time that you turned it on at home? With major temperature changes on a summit (especially at this time of year), I wouldn’t rely on just the computers internal clock without it being accurately adjusted from a known stable time source.
I thought it might be that but ruled it out. The last two summits I had mobile coverage and made sure the PC clock was in sync. Made no difference, I could see the time offsets were fine on the decodes anyway
JS8call and FT4 are on 7.078 14.078 .
My last SOTA on Digital I made 2 FT8 QSO and on JS8 12 QSO.
i joined a local VK JS8 .io group and notified that group via email before I went out as well as Alerts on SW3. The FT8 contacts were two JA stations who I have worked on other modes for SOTA so they took the effort to chase me on FT8 probably cw from memory.
I agree with Tom re difficulty out in the field it can be hard to see the curser on your pc screen I totally lost mouse control some of the time until i covered my head and pc with my rain coat so I could see the screen again. JS8call is easier to swap relevant information one on one in a qso but with fT8 i made a couple relevant macro files for CQ SOTA and Summit Reference to swap at the start or end on qso. Only made 2 contacts so I assume it went over all ok.
Keep up the good work
Ian vk5cz.
I find the FT4 frequencies are usually a lot quieter, but using FT8 there might upset some FT4 users.
You could use the standard FT8 frequency but effectively* using an offset of 2000-2700 Hz (or 2500-2700 Hz) and that would still be within the 2.7 kHz space.
*It’s probably better to use FT8 + 2 kHz as the dial frequency with a 500-700 Hz offset so you’re not right at the limits of the audio range.
While I like FT4, I find it harder to complete QSOs. People reply but then disappear. Maybe they decide they have a fear of MW callsigns.
I find the FT8CN Android app really useful because it means one less piece of kit to bring/forget/lose. I don’t think there’s an FT4CN app at the moment.
I talked to Lars about it. The FT8 activation plan looks like this:
First some CQs on the standard frequencies, e.g. 14074, to check the time difference delta t and, if necessary, estimate the propagation via the PskReporter.
Then look for a free frequency according to the band plan and spot there.
Lars studied the band plans and suggested the following.
I just noticed this revived thread and had a read through it from the beginning. As I’m reading (and amusing myself at what I didn’t know then vs what I know now!), my instinctive reaction was that the best answer to the question “FT8 frequency for SOTA?” is “FT4”!!
The standard FT8 frequencies on each band can often be too congested for a QRP SOTA station to cut through (or for possible S2S contacts) - true.
However, several previous attempted skeds on alternative QRGs have not really been particularly successful. A S2S might have happened, and maybe 1 or 2 chasers - but that’s it. For any sort of activity, it was necessary to return to the standard frequency.
FT4 is my preferred solution these days. The standard FT4 frequencies seem to have the “Goldilocks’ Porridge” (just right) balance between space and activity. Certainly on the main bands like 40m, 20m, 15m and 10m anyway. If sticking with FT8, then the WARC bands (12m, 17m, 30m) are often closer to that balance we need.
Alternatively (time of day, season and condx dependent) 6m or 60m FT8 can yield decent results on the standard frequencies. (Take care on 60m in the UK as the ceiling on the band plan for us is 5.358MHz - so you need your dial frequency on the standard 5.357MHz and a TX offset of 950Hz or below. It’s easy to be fooled because many non-UK jurisdictions do not have this limit, so you will see/hear plenty of activity between 5.358 and 5.360MHz. You can work them split of course (normal for FT4/8) but your whole TX signal must be below 5.358MHz in the UK).
Anyway, in conclusion, I don’t think the answer is alternative nominated frequencies for SOTA FT8. The practical answer is use FT4 - or the WARC bands on the standard frequencies.
