Tuesday, June 28, 2022

Future enchancements on VarAC

 Currently I'm testing and enjoying the newest VarAC digimode software. 4Z1AC Irad has started to implement Vmail (short for VarAC Mail) and there is now a possebility to leave a mail message at a station. This really works very well. This is just a start! From the VarAC fb page:

So what's next with Vmails?

You are only experiencing the first version of it. I wanted to release a basic functionality to start and get some feedbacks and find bugs, before I move on to the next phase which is the real deal.

Next version will allow you to store a message offline in your mailbox, and once connected to that station, the message will be sent.

Not only this, you will be able to park a message for a 3rd party (someone you don't have a direct link with). This will open up the opportunity for some people to have their rigs operate as a store & forward gateways. Much like an old fashion style of BBS.

So lots of things are coming your way. In the meantime keep leaving each other mails when they're <AWAY> . Seeing the blinking "3 NEW MAILS" is soooo fun.

73s! Keep Vchatting and Vmailing!


This is really most of the users are waiting for. Exciting!

Latest connections with VarAC:

Vmails from as far as CA, USA have been received! 

Monday, June 13, 2022

Experimental setup square halo (2)


 In between keeping an eye on 6m and 4m DX in the middle of the ES-season I tried to make some progress building the multiband square halo. Well, actually it is getting a multiband hybride square halo. Not that I really know what I'm doing but trying to build this antenna practically. Someone else can do the theoretical side if they wish. Reading the theory about the IL-ZX antenna W4RNL describes you have two options to multiband this antenna. Actually the first option is a second small antenna for 17m/12m above the one for 20m/15m. I'm not building 2 antennas but only one, so it is no option for me. The second option is sleeve coupling like my 6m/4m dual band yagi. I thought it was useful to investigate the option. So I took 8,2m of aluminium wire from the spool I bought for use with another project. I nested it between the 20m/15m wire. Well...I can write that it is no option. There is too much interaction and after installation of the wire 20m/15m lost their matching completely. Remembering my previous experiment using the 17m wire with open ends I thought just a single wire dipole would do the trick. So I nested a single wire connected to the balun, just a dipole for 17m. Yes, a perfect SWR on 18,1MHz. But again 20m/15m wire was totally not matching, could not even find a resonance point.

In the end I decided to get back to my previous experiment with the "open" loop, if you can call it like that. So, it is two wires together, only one is connected to the balun. It doesn't match perfectly but this is the best possible. Moving the wire closer to the 15m wire gives the best results. Moving it too close will affect the 15m wire, it is a case of experimenting. My best result was obtained at 20cm from the 15m wire. A side effect is that it seems that the bandwidth on 20m and 15m has increased now.

Now, I build an antenna to practically use. I want to hear something, work something. I really wanted to do some receive test and connected the FT-817 to see if I could hear something. Propagation seems to be not really good on HF but I was able to hear some signals on 20m/17m and 15m. I will now preparate the 17m wire for permanent installation and go on to the 12m wire...

So far I'm not disappointed. The station on 15m is from Bali, Indonesia. I believe I can hear a station from Dominican Republic in the background as well and an Irish station. The antenna is at about 2,5m height

Sunday, June 12, 2022

#6m Mexico worked

It was an incredible sunday afternoon. USA came in already early and propagation kept on and off and on all the time till local midnight. I've tried to work XE2OR a few times over the day, I saw this station from late afternoon till late in the evening. To receive stations from this far west from USA on 6m is very unusual. Of course I was not on the radio all the time but kept receiving and trying to make some contacts during breaks using remote on my telephone. Again PSKreporter does not report everything since I saw far more DX not shown in this map. I tried to call SSB several times but besides some european stations there was no DX coming back to me although some stations from USA/Canada at 50.323MHz sometimes did have a real S9 on my S-meter.

#4m Israel worked


Worked 4Z1TL first but erased my screen. Worked famous DXer 4Z4DX Dov second, this time I captured the screen...

#4m North Macedonia worked


Friday, June 10, 2022

#6m transatlantic propagation


There was some reasonable propagation to USA/Canada yesterday evening. My signal was received by many but only worked a few. The problem is the huge amount of european stations on 50.313MHz FT8. There is an alternative DX frequency 50.323MHz especially for DX but somehow it takes considerable time before DX moves there.

I also worked a new band DXCC which was D4L from Cape Verde. The contact was made on CW, very unusual these days :-). Early in the evening D4L had a real 599 signal over here. And since everyone is on FT8 you now have a chance to work DX with CW/SSB if you listen carefully.

Thursday, June 9, 2022

#4m strong IORT FM stations


From https://en.wikipedia.org/wiki/FM_broadcast_band

The OIRT FM broadcast band covers 65.9 to 74 MHz. It was used in the Soviet Union and most of the other Warsaw Pact member countries of the International Radio and Television Organisation in Eastern Europe (OIRT), with the exception of East Germany, which always used the 87.5 to 100 (later 104) MHz broadcast band—in line with Western Europe.

Countries which still use the OIRT band are Russia (including Kaliningrad), Belarus, Moldova, Ukraine, Lithuania and Turkmenistan.

The 4-meter band (70–70.5 MHz) amateur radio allocation used in many European countries is entirely within the OIRT FM band. Operators on this band and the 6-meter band (50–54 MHz) use the presence of broadcast stations as an indication that there is an "opening" into Eastern Europe or Russia. This can be a mixed blessing because the 4 meter amateur allocation is only 0.5 MHz or less, and a single broadcast station causes considerable interference to a large part of the band.

Monday, June 6, 2022

Experimental setup square halo

Finally there was some time to do some experiments with the square halo this weekend. A few hours because there was a weather change. 

First setup was 20m only:

PA9X told on his site this was quite easy, and it is. However the balun in the white box I showed previously didn't make things easy. I was not able to get a decent resonance and suspected the homemade balun. It was exchanged for a commercial Diamond BU50 balun. After that it was easy to tune the wire.

At first I was planning to put this in the tower and test how things would work. But I changed my mind and went to the next band. 17m was a pain. I could not get any resonance at all. It went better when I opened te ends of the wire, so it was just a half wave dipole. But still best SWR at resonance was about 1:2. Not shure about it but I decided to remove the wire and go on the the next band which is 15m.

This actually went well. Easy to tune. 20m not affected at all. But have to write both bands are quite narrow. Bandwidth about 200 KHz with SWR below 1:2.

Again tried the 17m wire. But still impossible to find a decent resonance or SWR "peak". Not shure how to solve it. The "loop antenna wiki" has something about halo antennas written. It is about the gap at the end. It is capacitively coupled. I might try to test if the ends of the wire should be closer or further away from each other. If any reader with more antenna knowledge has any idea?

The weather changed shortly after and it is now pouring wet. Good weather to be in front of the radio. But not for building antennas. I will solder and seal the 20m/15m wire now for permanent use. Hopefully there will be some more time to do some further experiments. My ultimate goal would be a omni directional horizontal small antenna for 20/17/15/12m which you don't have to tune much.

Update 07-06-2022: I found some info about the capacitive gap in relation to the resonance of the antenna like we try to design. It turns out that my thoughts were right.


Cebik W4RNL writes:

"For a multi-band antenna, you may have better luck separating the bands. 20-15-10 provides less element-to-element interaction than a 5-band version of the antenna, although the harmonic relationship of 20 and 10 meters may show some pattern deviations. Of course, a second smaller array for 17 and 12 meters makes a good antenna to stack on top of the tri-band model."

Friday, June 3, 2022

PA3FXT's PKW 6m yagi

 Neighbourstation PA3FXT Reinder requested some info on his aquired used 6m 5 element yagi made by PKW. Information could not be found on the internet. Boomlength, radiators/dipole length and diameter were known but not the position of all elements on the boom. I told him it would be possible to calculate and optimize the yagi with yagimax. Yagimax is quite an old piece of software that is only running in MS-DOS, so you need some software that emulates MS-DOS. I found DOSBox and it works well. I guess there are far more superior software programs out now but in my opinion they are not easy to use. Yagimax is quite easy. You have an option to maximize gain or f/b ratio just by moving radiators and dipole on the boom. So that's what I did. I f/b optimized the antenna for use between 50 and 50,6 MHz at 2 wl above groundlevel. I tried optimizing gain but got only 2 more dB and f/b ratio decreased dramatically. This are the results:

I used this software many years ago and think it is accurate. But I can't really verify if theory matches with practise. Reinder will have to find out by building and testing his yagi. Hopefully it will work like advertized.

Thursday, June 2, 2022

#6m First opening to north america/caribbean


Yesterday evening there was, to me, the first 6m seasonal opening to Canada and even Bonaire. I've seen a few USA stations as well but mysteriously they are not reported to PSKreporter. 9Y4D was also seen and not reported. I found more accurate and realtime reports can be found on hamspots.net. But hamspots is being reported from JTAlert which not everyone is running.

Anyway, PJ4MM was actually replying on my CQ call which I think is rather unique because he was called by many in Europe at that time. I logged him but am not shure he got my R report. It is not that important for me since I worked PJ4 last year. Worked VO1CH and VO1SO from new foundland Canada.