[SFDXA] M0JCQ's Ham Blog - "Top 10 FT8 Operating Tips"

[Bill]

      M0JCQ's Ham Blog <http://www.hamblog.co.uk>


  Top 10 FT8 Operating Tips
  <http://www.hamblog.co.uk/top-10-ft8-operating-tips/>

23 Dec 2020

I’ve been slow off the mark with this blog post, but years ago I posted 
my Top 10 PSK31 Tips for Beginners guide 
<http://www.hamblog.co.uk/top-10-psk31-tips-for-beginners/> and it was 
really popular at the time. I’ve held off writing this post, so that it 
could be a (hopefully) genuinely useful post, as opposed to just jumping 
on a hot trend!

Over the last few years PSK31 and its variants were replaced by a new 
data mode… FT8. This data mode has truly come to dominate both the HF 
and VHF bands, to the extent that it’s becoming rarer to find much SSB 
and CW activity, regardless of any other data modes on a given band!

The following tips are comprised of my experience of using FT8 for a few 
years, since it was first released back in 2017. I’ve had 3,000+ FT8 
contacts across bands from 160m right through to 70cm.


    1. Stick to a Single Frequency

This is probably where a lot of beginners go wrong. Try and find a clear 
frequency and then stick with it, regardless of whether you call CQ or 
respond to others. The /*Hold Tx Freq*/ option is your friend in WSJT-X:

Hold TX Freq option in WSJT-X

Hold TX Freq option in WSJT-X

This will ensure that you always transmit in the same place and 
importantly you don’t keep hoping around the band.

Why does this matter? Well, you’re more likely to be decoded if you’re 
replying to another station off of his own frequency. If you move to 
their frequency then you could be competing with other stations.

Also we’ve all had it, where we’re happily running on a frequency, then 
a station works you and then proceeds to stay there and call CQ on 
‘your’ frequency. It’s annoying and typically the other station isn’t 
even aware they’re doing it!


    2. Time Synchronization is Key

If you’ve used data modes like RTTY and PSK31 in the past, then you’re 
probably used to random receive and transmit cycles where you click a 
signal and transmit as soon as the other station has finished.

FT8 (and the other WSJT-X modes) demand perfect timing, so perfect it’s 
beyond most of us to get right! If you’re computer clock is off by 2 
seconds or more, then most likely your signals won’t be decoded by 
others, and no one else will even see your calls!

Your native Windows clock is likely to drift very quickly, unless you 
keep it trained to an accurate clock via the internet. I personally use 
Dimension4 <http://www.thinkman.com/dimension4/download.htm> to do this. 
It’s free and every 30 minutes it automatically synchronises my PC clock 
with an accurate reference online.


    3. Learn the WSJT-X Colour Coding

WSJT-X helpfully colour codes your decoded messages, so you can spot 
important messages quickly.

If a new DXCC starts calling CQ which you’ve not seen before then this 
will be highlighted in dark purple (by default), if it’s a new DXCC for 
you on the band, then it’ll be highlighted a lighter shade of purple. 
Useful!

It’s worth taking a look at the ‘Colors’ tab within the WSJT-X settings 
and learning these. This will allow you to quickly act on something you 
may ‘need’ like that rare DXCC or that rare grid square.

WSJT-X Message Colours

WSJT-X Message Colours


    4. See Where You’ve Been Decoded

The PSKReporter.info <https://pskreporter.info/> website is a very 
useful tool to find out first of all if you’re getting out, and secondly 
where in the world you are being heard!

This gives you an almost real time summary of the propagation on your 
chosen band, it’s a great way to just understand the possible HF paths 
which may be open at a certain time of day.

Being received well in JA on 20m

My messages were being received well in Japan on this day (using 20m)

I typically have this running and check it every 20 minutes to see what 
I might be able to work or how propagation is changing to favour a 
certain area of the world.

Observing this resource has allowed me to work a lot of DX:

Pileup of JA stations on 20m FT8

Pileup of JA stations calling me on 20m


    5. Persevere

One misconception is that FT8 can be like shooting fish in a barrel, but 
it’s not always easy to “work the world”. The vagaries of propagation 
still come into play. Conditions can change quite quickly with openings 
appearing and fading out.

If a station doesn’t respond to your call straight away, try leaving it 
calling them for a few cycles.

The conditions might just swing in your favour, then they can decode 
your message.

This is another great reason to operate away from the other station’s 
frequency; you can continue calling them while they’re in a QSO, without 
you interrupting it and you might end up possibly being worked straight 
after.

I used to give up a bit too quickly, but found that perseverance 
(especially with DX stations) usually paid off.


    6. Enable ‘Deep’ and ‘AP’ Decoding

Without going into too much technical detail here, your FT8 decoding 
will be more sensitive if you set your WSJT-X decoding settings to 
‘/Deep’/ and ‘/Enable AP’:/

Enable AP in WSJT-X

Enable AP in WSJT-X

Deep decoding throws more of your computer power at decoding the signal. 
While AP (a priori) uses heuristics and known information to decode 
messages, which otherwise wouldn’t be decoded.

Deep decoding comes with a performance penalty, your computer may not 
decode all received signals before the next time period starts. While 
using my old shack laptop, I found this to be a problem when decoding a 
busy 20m band, but after upgrading I use it all the time now. You can 
always drop back to ‘Normal’ decoding if you notice this.

Enabling AP on the other hand can introduce some unusual side effects 
with the decoded message. If the callsign looks funny, then it’s 
probably incorrect. It easy to see which messages had AP applied to them:

Decoded message using AP

Decoded message using AP

Use your brain here – if it looks funny to you, then it’s probably not 
right!


    7. Can’t Decode a Strong Signal? Lower your RF Gain

Sometimes you’ll see a large signal on the Waterfall, but WSJT-X can 
only occasionally decode it, but at worst just cannot decode any of the 
messages at all. The station seems to be transmitting accurately timed 
signals, but nothing shows up, how strange!

I’ve noticed this occurring during strong openings, especially during 
Sporadic-E season on 6m, where strong signals of 10dB+ just won’t decode.

I’ve found that simply turning down your rigs RF Gain will allow the 
messages to be decoded. A simple fix, but if you’ve not used other data 
modes you might not think to do this!


    8. Not Getting Many Replies to your CQ Call? Change Frequency

You may find that for whatever reason you are not getting any responses 
to your CQ calls. This could be down to a number of factors, but it’s 
always worth checking to see if your chosen frequency is clear within 
your chosen TX timeslot.

If another station is transmitting on your frequency or nearby during 
your TX timeslot, then other stations may not be able to decode your 
messages in order to even see your CQ messages.

Even if you still can’t see anything else when just receiving during 
your timeslot, there could well be another station on the same frequency 
which your DX is seeing, but you’re not.

I’ve found it worth while moving frequencies, if you’re not getting much 
luck, it usually works!


    9. Change Timeslots

If you’ve spent a while using one timeslot (say even TX), then why not 
switch to the other one? This might net you a whole new haul of stations 
to work.

For me this usually leads to an (initial) increase in contacts and 
obviously allows you to work stations not worked in your other timeslot. 
I tend to keep switching between these timeslots every 20 minutes or so.

How to switch TX timeslots in WSJT-X

How to switch TX timeslots in WSJT-X

A word of warning here: make sure there are no timeslot conventions on 
your chosen band. VHF bands have a convention where your timeslot is 
chosen based on your location, in order to prevent nearby stations 
interfering with each other, when you’re all trying to receive distant 
and weak DX. Your RF neighbours won’t thank you for breaking this 
convention.


    10. Pay Attention to all Received Messages to Spot DX

WSJT-X will decode all messages across the 3kHz spectrum of the band 
you’re using (or less depending on your radios selected filter). This 
can result in many decodes on a busy band like 20m.

I’ve spotted quite a lot of DX and then subsequently worked them, 
without ever seeing them call CQ! DX stations are often overwhelmed by 
stations calling them, so don’t often need to call CQ.

By monitoring all messages (not just highlighted CQ messages) in the 
left hand ‘Band Activity’ pane, then you might just spot some rare DX 
lurking. You might also notice a number of other stations calling a DX 
station during your RX timeslot. A simple switch to the other timeslot 
and you might just be able to decode and then work them.

This has netted me a number of DX stations I would have otherwise missed 
by just paying attention to CQ messages only!


      M0JCQ's Ham Blog <http://www.hamblog.co.uk>


    http://www.hamblog.co.uk/top-10-ft8-operating-tips/

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