Tuesday, September 26, 2017

PD1BM/HG9BM Silent Key, my memories...

Another good radio friend I knew personally suddenly died last Thursday. Bert PD1BM was a licensed amateur since 2011 but before that he was a very active DXer on 11m. We first met I think at the end of the eighties could be begin of the nineties of last century. Bert was a very enthousiastic DXer and his main goal was to work as many on 11m. He had a excellent QTH between 2 canals and a high mast with a big beam. So you can imagine DX was no problem. I vaguely remember I helped him getting the mast at his house many years ago. Bert was always in for help and had a lot of useful information about DX. Besides that he always liked to chat about the hobby and other things. I remember I attended his house a few times during my school time. After school I went to his house and most times we did some DX together from his small attic based shack which was more enjoyable of course. Unfortenately after my school time I was occupied by getting a job, family, cars and other things in life. I obtained my amateurradio license 13 years before he did and we didn't meet on the air much anymore. We kept some contact by e-mail and sometimes on air till Bert had to go QRT for a while as neighbours were complaining about interference. When he finally got his license I believe the neighbours moved and he could pick up the hobby again. We had some contacts but apparently he was DXing on other bands and had other interests as me so we didn't meet often. He didn't like contesting and was a real old school SSB DXer, he liked to have a chat. I knew he also had a house in Hungary and I have heard Bert on 40m when he was there but was never able to contact him. Last week I just found out he also had a Hungarian call HG9BM. Last time I met Bert was at a radiorally more then a year ago we had a nice cup of coffee and had a chat like the old days and of course we promised to stay in contact. I know Bert had a lot of good radio buddies and me and Henry were only a few of them. All of them will miss his very characteristic voice on the radio. It is all a great loss but, just like Johan who died last year, we will never forget him...

Excellent QSO between KI4ZZJ en PD1BM

In QSO both Bert as Johan on 11m as I like to remember them.

Monday, September 25, 2017

#cqww RTTY contest 2017

Event: CQWW RTTY contest
Section: LOW power all band assisted
Logger: N1MM+ 
Station: Icom IC-706MK2G at 40W
Antenna: Coppertape multiband vertical at 9m agl

Well I did it just for fun again. RTTY is not my favourite mode. I had very limited time too and only at sunday. Saturday was occupied by a family meeting and in the afternoon that day I got a phone call from Henry PG0DX with a very unpleasant message. Our good radio buddy PD1BM Bert suddenly died last thursday. So, you can imagine this cqww rtty contest didn't bring me the fun I wanted to have anyway. Overall I did hear some interesting stations but didn't work them all. Most interesting DX I think was ZF1A (Cayman Isl.) on 40m and XW1IC (Laos) on 20m. Especially XW1IC was very strong peaking S9+ in the evening. Didn't hear anything on 15m and above but that's because I was only active at the dark part of the day. I tried 80m but it wasn't working, I only got a lot of AGN? AGN? and so my participation was limited to 40 and 20m. Overal in 3 hours time 75 QSOs is average. I spend at least a half hour to solve the bandmap/frequency issue as it is described at several sites (even my own) and the manual you can find "Auto Update TRX Offset w/Mark Freq." in the settings of your Digital Interface window(s). Well it was exactly what I was looking for in settings but could not find it and it was my own fault as I should have read setup instead of settings. Anyway, problem solved...


Friday, September 22, 2017

Variable coupling loop

So I built a variable coupling loop. I'm not limited to 1/5, 1/4 or 1/3 size coupling loops like in the experiment I did before this way. During my experiment I tried several options and finally get best SWR all bands with a size between 1/3 and 1/4 size of the main loop. Especially on 60m and 40m the SWR is significant better. My advice to loop builders would be just to experiment till you get best results. You might end up with a 1/5 size or any other odd size coupling loop. I think all is depending on the size and material used for the main loop and the pickup loop, the capacitor, the coax and since there is a slight difference between homemade loops there is always a different result.



Actually I was a little surprised with the outcome of this experiment. I use a coupling loop now which is between 1/3 and 1/4 size of the main loop. SWR on 60 till 15m now is below 1:1.6. I think that is a very good result. I consider my magnetic loop ready to go now. Now next thing.....testing on air.

For those that are interested. My magloop consists of 1 box with 500pF varco (which has been described earlier), 3 pieces of PVC tube, A length of 2,7m bamboo 9 75 Ohm coax, a length of 80cm 6mm wire for the coupling loop, 2m RG58 coax.

At the right my 3 portable antennas. First is the MP-1 (in the white tube) with a tripod in the hama bag, at the center there is the magloop and the last one is the PE1BVQ 3 band endfed with 5m Aircell7 coax. The Aircell7 coax is also used for the MP-1 and the endfed needs a tree or mast to hang the wire. The magloop is the only antenna which includes everything to transmit/receive without any extra supports or any other accessories.



Thursday, September 21, 2017

The shielded faraday coupling loop myth and other considerations

Most common made "shielded" faraday loop
Experimenting with the magnetic loop is still going on. To couple  the loop to the feedline I use a faraday loop inductive coupling in my loop. Now there are several designs, shielded and unshielded. The main advantage of a shielded loop would be canceling out a vertical or horizontal E-field (electro magnetic interference) or both. The question is if this would be really working?

Some explanation of this theory has been given on N4SPP's site:

https://www.nonstopsystems.com/radio/frank_radio_antenna_magloop.htm

However, W8JI has written many articles about antennas and has been working as a tech at a commercial radio station. This is what he comments on the internet:

There is no such thing as a "Faraday shield loop". All radiation and reception comes from the shield. Always. Just like it is a single turn conductor.

The idea you can shield the loop is as silly as the idea you can shield a ground lead.

Once you understand that you will also understand that the only way to not have common mode on the feedline is to make the shield perfectly symmetrical about the feedpoint and have both sides of the "shield" symmetrical and identical with the grounding and feedline entry.

My website shows why high frequency fields cannot penetrate the shield, and why the radiation and reception all comes from the outside of the shield.

A shielded loop is electrically no different than a equally balanced unshielded loop.

W8JI

Some others comment that the so called shielded faraday loop helps to balance the feedpoint. However, it is all about the feedline that radiates or pickup noises. So a simple 1:1 balun or RF choke should do the trick. You see something like that at the Chameleon loops.

Well, technically speaking or writing it all sounds likely. But I don't like likely and want to test and experiment myself. All what counts is practical use, you can only transmit and receive theoretically in your dreams ;-)

I want to know the difference in receiving interference with a shielded and unshielded coupling loop if there is any difference? Besides that I want to know why many use 1/5 diameter faraday loop and others use 1/4 or even 1/3 diameter? Well, first of all I did a test with two faraday loops 1/4 diameter size. One unshielded the other one shielded as in the picture above. See my not so scientific practical test in the video:



What it revealed to me is actually in the video the shielded loop did receive about the same RFI compared to a unshielded loop. I did not move the loop and I did not move the PSU wich caused the RFI.  The RF choke made from about 8 ferrite cores doesn't help much it seems, although it could help for transmit purposes? Myth busted? Well I don't know for shure, but my practical test shows that you can also use a piece of cheap electrical wire and bend it in a round shape then connect it to a coax with just a thermoplastic connector or solder it to the loop.

And well, I did just that to test more faraday coupling loop sizes. A practical experiment. I made 3 faraday loops. 1/5, 1/4 and 1/3 diameter (compared to the main loop diameter). All loops did well and minimum and maximum frequency with reasonable SWR were the same. However if you need a good SWR on a low frequency you need a bigger coupling loop and for a good SWR on a higher frequency you need a smaller one (at least that is what this test reveals). A good average is 1/4 size. I measured the SWR with my MFJ259 analyzer.

Coupling loop diaFreq.min60m40m30m20m17m15mFreq.max
1/54,1MHz
4,4
3,32,51,811,41,223,1MHz
1,6
1/42,52,51,51,31,91,51,71,3
1/31,41,11,41,82,521,81,1
Shielded coupling
loop 1/4
32,31,51,31,51,71,41,3

I'm not the only one that discovered this of course. There are so many things tested and written about the magnetic loop including articles about different feed methodes, skin effect, impedances, radiation resistance etc. ect. But I found only one document from a american experimenter that used a variable coupling loop. Great idea....but he used a square loop and a square coupling loop which is easier to adjust.

Just for testing purposes I made a adjustable coupling loop. I can bend/slide it from 1/3-1/5 size of the main radiating loop. That test revealed about the same as above done with 3 different loops. However I was not limited to 1/4-1/5 and 1/3 size but could get anything in between. While testing it became clear to me that a 1/4 or 1/5 size is not always the way to go. But that story takes too long for this post so I write more about that later.


Tuesday, September 19, 2017

Tune indicator


Interesting video which shows a very simple indicator. However it only works well with a endfed type antenna. I've tried it on a loop just besides the varco, the led blinks but not at the right moment.
I remember in the past I had a commercially made simple clamp on meter which you could clamp on a mobile antenna to tune it without the use of a SWR meter. It is just the same as this device, although this one is fun to make and a lot simpler and cheaper.

Thursday, September 14, 2017

Still think it is a miracle


FT8. Started at the highest band with propagation which was 15m. But only one weak signal was received. 17m much more DX, but my signal didn't come out, at least I was unable to work the DX, same for 20m. 30m some more luck, but no real DX. 60m same thing.....ehhh, but then....the miracle happened. So unfortunate Australia is still not allowed on 60m. Great report -15dB from VK7BO Tasmania. I was working with 15W FT8 on my multiband coppertape vertical.

Wednesday, September 13, 2017

Could this be a future for #HAMradio

No, I have no connections with the company or business that have this idea. But I wouldn't be surprised if some radioamateurs were involved. Could this be a future for HAMradio and especially for emergency comms? I think this is a great idea!

Gotoky is device which allows you to stay connected with your friends and family no matter where you are. Gotoky connects to your SmartPhone wirelessly and allows you to seamlessly connect with other users within the range up to 5 miles or 8 kilometers through your Smartphone app. It works over standard license-free radio frequencies and it does not require any cellular infrastructure or satellites. You can talk, send/receive messages, send/receive location information, SOS signal and much more to other gotoky users for free. It is also compatible with standard Walkie-Talkies.

Well to make a long story short. This device turns a transmitter into a telephone network including text messaging etc. etc.  it has so many features especially if you are in need at a remote location. The device has a range of 5-15km but if it is compatible like they write I think the range for us radioamateurs could be significant higher. However, radio regulations for us as licensed operators could be a problem to use this device worldwide. Besides that you still need a smartphone to communicate, most of us do have it. But still a lot of (older) people don't. And there you have it, the average radioamateur is "old". The technology is available but I think it is going too fast for most of us within our hobby.  However, this could be the future also in our hobby!


Tuesday, September 12, 2017

#FT8 digimode again

20m waterfall FT8
Well it has been a while ago I wrote one of the first user blogposts on the internet about the new digimode FT8. Since that day this post has been read about 5000 times. Not only it seems to be a successful post but I got many e-mails as well with questions. It seems to be they think I know all about it ;-) Well, I've not been a lot on FT8 actually and I only updated to RC2 version of WSJT-X this evening. Other things kept my mind and this evening I was not able to transmit only receive. The problem is that the solar powered battery I use to power my autotuner is at the end of his lifetime and it died actually. But still I was able to do a 20 minute receive session from 160-15m. I was astonished about the amount of stations on all bands with propagation here. It is difficult to find a clear spot on the waterfall as you can see in the screenshot above. This was the result after 20 minutes switching between bands:

Results 160-15m. Click for bigger picture.
Even Australia on 80 and 30m was no problem to receive with -21dB. I really don't know how propagation is these days as I don't listen much HF these days. But this result gives me a wow factor. At the moment FT8 seems to be very good for a quick personal propagation research. Take about 4-5 minutes to receive per band and you know what is possible...

Sunday, September 10, 2017

Balloonfoxhunt 2017 report from the north

Well, not a great show. Although the organisation did their best to build in a surprise element. This year it was unknown were the balloon would start so a prediction could not be calculated at all. It would be a real foxhunt and in the end due to technical problems it was even a foxhunt for the organisation. However, the wind was south-west and I'm living in the opposite direction so there was a good chance the balloon would head my way. I started listening late and my first reception was in the car on my baofeng HT. It occured to me that I could only hear a weak tone of a beacon and no transponder although this year there would only be a transponder? Strange! It seems there was a technical problem with the receiving part of the transponder on 70cm, so almost no one had the ability to work via the balloon, only a few stations with stacked yagis and power had some luck. For me that was a big downer. However, remember my efforts to try a QSO on the 70cm PI2NOS repeater without luck in 2015? Well it seems the repeater has better ears this time and I worked the headquarters of the balloon organisation to let them know I received the ballon at that moment with S9+. So unfortunate the transponder was not working....

At the end the balloon was hunted down in Germany near the city of Munster.

More info at: https://www.ballonvossenjacht.nl/


Thursday, September 7, 2017

More magnetic loop experiments

Experimenting is the main thing of this hobby I think. So, my goal this time is to make a usable small portable magnetic loop that is reasonable easy to tune. There are several designs that you can find on the internet and some of them claim to be better then others. I choose the coax version for myself as it is light to carry and can be very small. I discussed some possebilities with PE1BVQ Hans and he gave me the measurements of his own loop that does well. I already had the 3x 500pF varco from him and decided to use it again but in a bigger box. The problem of tuning still is very difficult and Hans told me I should build a reduction. Glad the box is big enough.... I first thought of building another varco myself but let that go eventually. I have the luck to have a colleague that happens to be also studing for mechanical engineer and he always has good ideas. He designed a reduction system with isolation (less handeffect) from scrap and some new parts. The idea is simple but effective, this guy has nothing with my radio hobby but though of the exact good solution within 5 minutes. I think that is incredible! And besides that he helped to realize the mechanical part. We finally build this together and tuning is now a lot easier.

But still I would like to have a indicator besides the indication at the tuning knob. It should be no problem, but that is another experiment. Now, I was thinking of were to really use this antenna in case of emergency. And just when I was thinking this video shows up:


Of course you use it inside a shelter. I would use it in the basement as that is the most safe place in the house when disasters like hurricanes will happen. When my loop is ready I will test it for shure and post a video, at least that is the idea...

Tuesday, September 5, 2017

SSTV 17 years ago

Coincedentally I came across this capture of a SSTV image sent by me almost 17 years ago when searching (googling) for another subject. Around that time I have been quite active with SSTV on UHF.  Some of the components you see on the picture are still in my shack. The cat has died several years back.

Other things, jobs and tasks are taking my time these days. And although I'm always busy with the radio hobby I can't finish several projects and write about them here. Where a project would take a day or two for others it will take a couple of weeks or even months for me at the moment. Last weekend I decided not to take part in the fieldday contest this year and it could be I will cancel other activities as well. Don't be afraid I will never stop with this great hobby, that would be no option. I will only stop when I die and even after that people will be able to read about my experiences from this blog :-)


Friday, September 1, 2017

#IARU R1 Fieldday SSB this weekend

Just to remind you all that the IARU Region 1 fieldday SSB is this weekend starting Saturday 2nd September at 13:00 UTC.

I'll probabely take the opportunity to test various antennas at home. The photo takes you back to 2 years ago when I was taking part from the Eemshaven (harbour) near my QTH.