Tuesday, 24 January 2017

Leave those "touch" switches out of the house

My XYL would like to have some more light on the kitchen counter . So I found a suitable LED light. Not some cheap chinese alibaba light, no, it costs at least 50 euro. It is a high quality LED light with integrated touch switch. It works fantastic and it gives a lot of light. But with some trouble in mind reading about touch switches in several forums and sites from other HAMs I asked the guy in the shop if I could test it first before I buy it explaining the hamradio troubles. He agreed and I went home to test it. Well, on the vertical antenna which is standing 10-15m from the house there was no trouble at all. But then the horizontal loop. On 60m and 40m with 100W it gave me the trouble I didn't want. Flickering lights when transmitting. So, I brought it back to the shop. I know that many have trouble with these kind of switches and tried to solve it by filtering, I don't know if anyone succeeded? I did a simple test with ferrite but it doesn't solve anything. Touch switches well I don't know....I leave them out of my house and environment. I hope the neighbours will never get them as they probabely will think there is a ghost in their house switching the light on and off all the time.

Above the test and experiment in video. I bought a roll of flexible cheap chinese LED strip with a infrared switch and remote control it's even dimmable, A small test today under the same circumstances revealed it was not affected by RF at all. Price: 15 euro. Think about it...

Thursday, 19 January 2017

JTDX - DXing with JT digimode

JTDX means "JT modes for DXing", it is being developed with main focus on the sensitivity and decoding efficiency, both, in overcrowded and half empty HF band conditions.

It is open source software distributed under the GPL v3 license, and is based on the WSJT-X r6462 source code. Optimal candidate selection logic, four/five pass decoding and decoders based on the matched filters making JTDX performance quite different from WSJT-X software for operation on the HF bands. Almost all work goes around JT65 mode, decoding efficienсy of JT9 mode is the same as in WSJT-X and might be addressed in the future JTDX versions. Initially based on the enthusiasm, now in average it taking close to 12 hours of daily work and your donations would be the only way to let me proceed with the further JTDX software development.
Many thanks for your support,
73, Igor UA3DJY

When watching PSK reporter lately I noticed most stations are using JTDX instead of WSJT-X or other software these days. So I thought, what could be the reason? This software has to be the top if so many use it. I installed the software latest version and first impression is that it looks a bit different from WSJT-X although it is based now on the latest WSJT-X 1.7. After some playing and configuring I was courageous enough to dare a TX cycle and suprisingly 3 calls came back, all 3 with only 1Hz apart from each other. So, I actually saw one signal in the waterfall but it was at least a layer of 3!!! I have never seen this in WSJT-X. Wow! I picked the weakest station (-20dB) while the other stations were at least -10dB and -6dB. After a few days I noticed that even weak traces half behind strong signals are decoded, something I hardly experienced with WSJT-X.

Some features not seen in WSJT-X:

To work stations faster I notice more and more stations are using the feature "skip locator" in JTDX, with other words they come back with the report directly in response on a CQ. This is especially useful for DX stations with large piles of calls waiting to make a QSO as fast as possible.

A SWL button increases the amount of decoding attempts. Realize that it will take a faster computer to decode everything before your transmission session will begin!

There is the "hint" decoder button, although I probabely will not use it. It is interesting development but I personally think it is cheating. The "hint" decoder looks for a hint in a file with calls and displays the best possible call it can find, it is to the operator to use it or not for a QSO. It actually is the same as the hints you can get in a contestlogger like N1MM(+). That is actually cheating as well although it helped me numerous times. Anyway, you don't have to use the "hint" decoder of course and actually most of the time JTDX is receiving well enough to do without it.

The filter button is another nice one. A passband filter for the desired signal especially usefull in crowded band situations.

While I was writing this article the software is still developed and another feature has been implemented which is a button for AGCcompensation. Not shure what it does, I've been switching it off/on but am not shure what the difference is? This is what the official release notes tell: AGCc button: use it only if AGC being triggered in receiver by JT signals at beginning of the RX interval. Noise level change in the waterfall might be used as criterion showing that AGC is triggered in the receiver. 



It is recommended to read the JTDX documentation and release notifications before installation.
I had trouble with the performance of my computer with this software package as I still work with my 2008 Intel dual core 2,6GHz. Sounds fast, well not for todays standards. The problem was that my transmitting audio started 3-6 seconds later after the actual transmission (in time) start. First I thought it was JT-Alert in combination with JTDX but without JT-Alert running I had the same problems. The original settings are for up-to-date not too old computers. I use both attempts and passes two steps less as set by the software when you install it. Till now with good results. Below something you have to consider when you got a slower computer.

Advanced settings tab:

- Number of decoding attempts: set it as per required decoding time. It might be set to 1 if CPU frequency is 2GHz, and set to 3 if CPU frequency is equal to 3GHz. Higher values make better decoding performance.
- Number of decoding passes = 4 (may be set to 3 or 2 for CPU frequency less than 2GHz if decoding attempts=1 is not enough to get into 10 second decoding time). For VHF usage optimal number of decoding passes = 2, and number of decoding attempts may be increased to improve decoding efficiency.
- Hinted decoding DT range = 1

I've been using JTDX now for a few times/days last couple of weeks and notice that it is very addictive. It simply detects so many signals. There is always something interesting to see in my opinion. Have you ever seen 3-5 different stations coming back on your call all at once? With this software you have to actually choose who you make QSO with first. Well, I hope I've helped some of my blog readers to get a better JT digimode experience. Now, back to the radio and make contacts...

Sunday, 15 January 2017

FSQ (Fast Simple QSO) mode experiment

Remembering my V4 chat efforts back in 2010 experimental chat mode software I tested with Kees  PE2KM? Well, ZL2AFP made another experimental chat mode software called FSQ or Fast Simple QSO in 2014. It is available as standalone program and you will find it implemented in FLDigi. I installed the software half a year ago but was never able to test it on air as I simply did not receive anyone to test and experiment with. Now, I came across a message on OH8STN Julian's blog that he organized a experimental weekend for FSQ mode this weekend and so I was eager to participate in this event. Unfortenately I had only some time at Sunday and kept the radio on 10.144 MHz FSQ to monitor and to send so called "sounding" beacons every 10 minutes. I was actually happy to see that I received OH8STN and OH5KUY. The chat with Julian went very difficult but I actually had a nice chat with Ari OH5KUY (see screenshot above).

I received a image from Julian in which you can see the logo from his weblog Survival Tech North. I send out 2 images personally but don't know if anyone received them...Anyway, the first experimental FSQ digimode contacts have been made and overall I liked it a lot more as V4 chat back in 2010. The advantage is that it is implemented in FLDigi and that program can be installed on alternative operating systems as well.

Link to FSQ software and documentation: http://www.qsl.net/zl1bpu/MFSK/FSQweb.htm

Thanks Julian OH8STN for letting us know that this event was on. I know for many it was the first time on FSQ and a lot of first were made. FSQ seems to be very interesting especially when you have a couple of friends on the air.