Thursday, April 4, 2019

15 things on FT8

I read this most interesting article from VK3BVW Rob lately. He did some observations on FT8 last year and it gives a insight on some techniques that are available with FT8 QSO mode. Some of them are already known some not. You can always learn from it. I lately hear and read complaints about not needing any kind of techniques or operating practise with FT8 as DX mode. Indeed the classic techniques you use with CW and SSB are not usable. You have to learn new techniques. Some of those are already described in ZL2IFB's FT8 operating guide. But the observations done by Rob are certainly interesting. However Rob didn't describe them on his blog but instead made a video. Personally I'm more of a reader. Watching some video doesn't impress me and most of the time I forget what they told. So, I hope Rob doesn't mind, I will point out the 15 observations/techniques and ad my own thoughts to it. Hopefully we will learn from it.

FT8 @PE4BAS


#1 WSJT-X on OS X
I can't tell about it. But I know it can also installed on Linux and works well from what I heard. Personally I have W10 on all computers. Lately I went back to JTDX since it features some configurations that are very interesting for the DXer.

#2 The ALC debate
Many times you hear that if you're transmitting and your meter shows a ALC reading your signal will be distorted. I own a Icom and a Yaesu. With the Icom I sure try to minimize ALC till it is not readable. With the Yaesu I need some ALC reading otherwise it will transmit only 50% of max. power choosen. Rob is using a Yaesu FT3000DX and observed a similair thing.

#3 Using Pre-amps, NB and AGC
Although it is better to leave everything off sometimes you can need some help. Especially on 15m and up it can be beneficial to use a bit of pre-amp. Same for ATT (attenuation) on 160m-30m. Rob does consider RF-gain at a later point.

#4 Notch filter use.
I think it is controversial. However under difficult circumstances it can be your last help to receive the DX station. JTDX has a kind of "notch" filter on board although it receives everything but only displays the station that you pointed at on screen. It is not really a notch filter...
The only problem using a notch filter is that if the station decides to transmit somewhere else in the waterfall, since they noticed you are having receive problems, you will miss the signal! So be aware of that using a notch both on radio or the JTDX filter option.

#5 Taming the RF gain.
This is something I never tried. A new one trick for me. I think it is very important to set both RF gain as Audio input at the right level. Something that can vary between bands. I tried this trick and found it very useful when I had difficulties receiving 3D2AG, very useful trick especially when using it in combination with a noth filter or CW filter in my case.

#6 Pitfalls in the waterfall
The waterfall is no spectrum analyzer or panadaptor. It is just a representation from signals on air. A easy way to find a station or find a quiet spot to transmit on. Don't use it to determine signal quality.

#7 Getting a eyeful & #8 The colour palette
Well it is obvious that most radioamateurs are getting old. And so do our eyes. You can set fonts and colors in both WSJT-X and JTDX to your own needs. Rob gives a good example in his video.

#9 That darn noise floor
Absolutely true. Something I experience regularly. Overall I have a low noise floor compared to other stations. Most of the time that results in reports that are way worse as the reports I give. These days most stations have a high noisefloor especially when living near or in a city. However I experienced some ocassions when the opposite station had a lower noisefloor. Most of the time those stations are using a dedicated receive antenna.

#10 Work Split
This I've always told from the beginning of FT8. Split is most important. Don't transmit on the frequency of the calling station, reply anywere else in the waterfall were no signal is appearing. It is for that matter also important to view at least 2 time slots before transmitting. The reason is that there is a possebility that more stations are replying at the same time. If everyone is transmitting on the same frequency there are no decodes.

#11 A couple of QSO strategies
Now it gets interesting. I guess everyone has his own techniques. But it can be worth to try another spot in the waterfall or even transmit on the callers frequency if everything else fails. Moving your transmission frequency however is a difficult decision because the opposite station could use a notch filter or the semi-notch filter from JTDX and completely miss your signal. I lately noticed another technique from the calling station. Transmitting TX MY QRG. I already made a preset message for that as well, till now never used. But it can be handy!

#12 Studying the propagation
Propagation changes every minute. It can be there and next minute it can be gone. Rob does also propagation research and uses PSKreporter, Hamspots and WSPRnet. Personally I prefer PSKreporter for FT8. You can gather much info if you monitor a band for 24 hours. However I noticed that not all stations heard are being send to PSK reporter. For example my QSO with 3D2AG was never found in PSKreporter while other stations were reported at the same time...

#13 Digital in times of poor propagation
The time choosen for exposure of FT8 is just right. We are at the bottom of the solar cycle and the popularity of these modes are certain, thanks to these circumstances. Besides that even a modest station can get to the DX that was impossible to work before.

#14 QRP is fun
Well, it is indeed. Why using 100W if you can do it with just 5W. It's just fun! Unfortenately FT8 is not as sensitive as JT9, I made regular DX contacts using my FT817 with 5W JT9. It's harder with FT8 but still it is fun.

#15 Don't forget WSPR!
Rob promotes WSPR when not using FT8 or other digimodes. It gives important info. I like to do some WSPR as well collecting DXCC with just 1W. I'm now counting 91 DXCC so far but it is difficult to find some new DXCC. I hope the activity will increase. I would be nice to see that a DXpedition would setup a cheap WSPR TRX for propagation research for themselves and for others. Till now only VK0EK did something like that I believe. Unfortunately never received it.


I lately read a lot about the 60m band as I'm interested in the propagation there. Many times I read that oldtimer HAM operators are abandoning the 60m band since there is only computergaming on there according to what they write. I can imagine their grief, they had to earn their contacts and DXCC with CW and SSB in previous years. Now everyone can DX easily and especially FT8 is very populair on 60m. Personally I have a lot of fun DXing with FT8 and it requires a totally different operating technique compared to CW and SSB. On the other hand the fox/hound mode doesn't need that much technique, you only need to search for a free place to transmit and wait because you're the next in line. However the 15 things above can help you with the technique when fox/hound mode is not used at the DX station and considering the popularity of FT8 I think many will find this a very interesting read.

6 comments:

  1. Hallo Bas, interessant artikel. Veel dingen doe ik al, zoals temperen van de RF gain, Split werken, ALC zonder uitslag op de meter ( 50 watt -> 25 watt uit) Wat ik wel mis is de AGC gebruik. Sommige zeggen om dit uit te zetten. DX-en doe ik eigenlijk weinig. Ik zie wel wat op mijn pad komt. WSPR gebruik ik nog steeds, meestal met 1 watt of 500 mW, wel zie ik een afname van WSPR gebruikers. Met name hoeveel gebruikers ingelogd zijn bij wsprnet.org Fijn weekend, 73 Paul

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  2. Hallo Paul, ik had dat nog nooit gedaan met RF gain. In sommige gevallen kan het helpen. AGC gebruik, ja de meesten hebben AGC op off staan. Bij mij zie en hoor ik eigenlijk geen verschil. Hangt misschien ook van de set af? Voor gebruik van JTDX word AGC off wel aanbevolen. Het probleem met WSPR is de verkrijgbaarheid van teveel TX zendertjes. Terwijl ontvangen veel belangrijker is. Ontvangen kan ook heel eenvoudig met een RTL stick/SDR of gewoon een wereldontvanger. 73, Bas

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    Replies
    1. Ik had er ook nog aan gedacht, zo'n Sotabeam WSPRlite maar ik vind dat ontvangst ook belangrijk is want als iedereen gaat zenden maar niet meer ontvangen dan houdt het ook een beetje op.

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  3. Paul, bij de Yaesu FT817 is er wel veel verschil tussen AGC aan/uit. 73, Bas

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    Replies
    1. In negatief opzicht lees hier maar....

      https://pe4bas.blogspot.com/2018/09/the-case-of-failing-ft-817-s-meter.html

      Ik laat AGC mooi aanstaan tegewoordig...73, Bas

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Thanks for your comment. Bedankt voor je reactie. 73, Bas