DATA MODES WITHOUT COMPUTERS
Being relatively new to the Amateur Radio hobby, I've never experimented with PSK or RTTY and I thought it was about time that I tried it - after all - experimentation is what this hobby is all about, isn't it??
Thankfully, the ICOM IC-7610 has a built-in Decoder for PSK & RTTY, so no computer is required. At the back of my mind I'd always linked software to operating these data modes and I've always felt that I've got enough on my plate without having to involve computers, software and drivers.
It was G4ILO's great enthusiasm for the mode which originally got me interested and I was very sad to hear that Julian passed away. Apparently, he'd been battling cancer for quite a while and finally succumbed to it 😢
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| Julian Moss - G4ILO - RIP |
One of the things that I learned straight away from Julian's blog was to take great care not to transmit bad signals on PSK. InterModulation Distortion (IMD) was apparently a huge problem due to poor or careless operators transmitting very distorted signals which would wipe out other operators on the band and make it impossible to decode messages.
Measuring intermodulation distortion of course, is not an easy thing to do unless you have specialised equipment, so most operators just ‘ wing it ’ by dropping their ALC levels and hoping for the best. Julian chose to invest in a very neat and affordable meter which gave clear indication of your station's IMD - KK7UQ's IMD METER!
These meters are pretty cheap and can be found on the secondhand market for around £50. I got mine on eBay - a bargain. Of course you don't need one of these, but it's good to know that you're running a clean station and not causing interference to others. That is, after all, part of our licensing conditions.
So the IMD Meter is super simple to install - there are no connections to your computer, radio, or even antenna. You just sit it in the shack, raise its built-in telescopic aerial and away you go!
It's always difficult to go into a new mode of operating when you're brand new to the game. The very last thing I wanted to do (apart from transmit noisy signals) was to interrupt other people, annoy them with my rookie attempts and get flamed!
So I looked around the internet for some tips on how to start. Thankfully, there's some great advice out there for learning both PSK and RTTY. It seems that PSK can be more of a chat environment, whereas RTTY appears to be made up of brief 599/73 type activity. I might be wrong there, but that was my initial impression, so I might end up coming back here editing this paragraph, 😂. In any case, I don’t think there’s a great deal of RTTY activity these days.
Anyway, I decided to start with PSK and the first thing to do was find out where the signals are to be found on the bands, so a quick trip to the RSGB BandPlans revealed the correct part of the spectrum to be tuning into for the digibands.
With the correct frequency range tuned in and the IC-7610’s decoder switched on (it’s visible in the Menu once you’re in PSK Mode), I started to watch the messages going backwards and forwards. It all seemed a little confusing at first and I wasn’t sure at which point I would be CQing or responding to a CQ. So I watched for a while and followed other people’s interactions and did my best to learn about the best operating practises in this mode.
So I started with the 20M band because that's where my EFHW antenna is most efficient. Tuning into 14.070.150 brought in a stream of messages between operators and it allowed me to get an idea of how people were using PSK and what sort of exchanges were favoured.
Following particular individuals, it soon became apparent that some operators liked to 'chinwag' just like on SSB, while others were less keen on that and simply wanted a short exchange for the log.
The IMD Meter showed that my transmissions were perfectly clean at -34dB which makes you feel good that you're not splattering the band with distorted signals.
The other thing I'd have to learn about is all the abbreviations! I'm obviously familiar with most, but some I had to look up like KN and OM. My overall lack of knowledge of this mode led me to start off by responding to CQ's rather than me calling CQ. I usually do the same in FT8.
It's been a very enjoyable start to learning to use PSK and (like FT8,etc) I'm sure it's going to be a regular mode of operation when the bands are quiet on SSB phone.
Common operating frequencies...
If you're a newly licensed operator and have never tried PSK, give it a go! It can be fun.
2 comments:
Interesting Tom, it gives an insight on how fairly new operators look at this mode. I was already experimenting with PSK at the end of last century (wow, that sounds like a century ago hi). PSK became very populair and it was the easiest way to always make a QSO just like FT8 is now. It surpises me that there is still some PSK activity. About 7 years ago there was an interesting derivation from PSK which was SIM31. See: https://pe4bas.blogspot.com/2014/02/about-sim31-sim63-digimode-again.html. It was a mode much more sensitive compared to PSK and also used some macros. It was the first digimode that could be used for automatic QSOs/logging, although illigal in most countries. I did a lot of PSK till 2015/16 when JT65A/JT9 and eventually FT8 did win the digimode popularity. Interesting, I still have a standalone PSK transceiver that only needs a computer and an antenna for 20m. I should try it again....read about it here:
https://pe4bas.blogspot.com/2017/03/qrpver-20m-psk-version-test.html. Who knows the PSK rage will revive after people reading your blog ;-). 73, Bas
Hi Bas, thanks for the visit. I will certainly give those links a visit. I love FT8, but I must admit that PSK offers a potential "chat" which is great when the conditions are poor. 73, Tom, M7MCQ
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