18 Nov

More 80m yagi repairs

This weekend I managed to pull a few more hours of work on the 80m yagi. All the elements were guyed properly last weekend, thanks to Hans SM0BYD for the help! This weekend I concentrated on changing the contol cables for the relay boxes on the elements and also reviewing their status. I brought the relay box for the driven element home since I need to change both control cable and incoming coaxial cable. It's getting cold outside so better do this stuff at home where you can stay nice and warm. During the week I discovered that the control relay matrix that was up on the antenna was broken. I made this so I could only run 4 leads from the house and control all different relay combinations, since the reflector/director and driven boxes are configured differently depending on what band segment the beam is at. I'm not sure what the cause could be but perhaps lightning that killed a few 800V 4 amp diodes! When I was about to test the relays in the driven element box one of the relay packs had a short circuit, I started investigating and also found a shorted diode on one of the relays. So I changed it and now everything seems to be working as it should. On saturday eveneing happy about the successful box repairs I cooked a great schrip soup for myself and my girlfriend, it was really delicious =) We had some perfectly tempered dry Riesling wine with the soup that we brought back home in the summer as we toured the Mosel valley in Germany. On sunday the weather was perfect to continue outside so I drove up to the station and replaced the control cables to the outer boxes. Dag SM0KDG also came up and he did some mods to the lifting device we have on top of the mast pipe. Drilling in the thick pipe whilst doing rope access! Dag also painted all the hardware myself and Hans put on the guy wires last weekend, like turnbuckles, wire-locks etc. Great job Dag! Here are som pics from the weekend!

73 de Teemu SM0W

3 Nov

80m beam repairs

This friday afternoon myself SM0W, Hans SM0BYD and Dag SM0KDG made repairs to the 80m yagi. Dag painted new steel hardware for the new rotator and assembled one of the bearing-plates for the rotator while me and Hans repaird the 3 broken elements. On saturday I also drove up to the hill and made re-inforcents of the 3 halves that was still intact. So they should be ok now. We are approaching winter and the plan is to get the antenna up before snow. But there is still lots of work to be done. Some pics from the weekend.

30 Oct

miniVNAPRO Bluetooth mod

This summer I bought a new miniVNA PRO for making various antenna measurements. I already had the old original miniVNA but it was bugging me I could not do a real OSL calibration to null out the measuring cables and also I was curious to use the Bluetooth functions since struggeling with 1/2 wave measuring cables is  a big mess sometimes.. easier to just put the miniVNA in the feedpoint and measure via Bluetooth on the ground. However, my first trials was very dissapointing. When I put the antenna at 20m height it was no longer possible to measure with my laptop, it worked with an external bluetooth dongle wich obviously had better RX/TX thanthe built in module in the laptop.. However this bugged me for a few weeks until I opened the miniVNA PRO last night to look inside, found the tiniest of tiny chip antenna and decided that I will put a bigger antenna on the device.. which I did last night and my first tests today show I can measure at a distance of at least 100m when there is line of sight!

This is what I did basically. 1.) Located the tiny chip antenna, soldered it away 2.) Found an old wifi AP and took the antenna and internal coaxial from it. 3.) Soldered it straigt to the Bluetooth chip 4.) Enjoy!

Here are some step-by-step pics.

27 Oct

Worksunday 2013-10-27

Last sunday I made a couple of hours of work at the station. In between I made som Q´s in CQWW SSB that was raging on. On saturday I attended a christening so I was not able to do the whole contest. Also the weather was quite decent for outdoor work so I made my priorities to work with the broken 80m yagi. The new rotator was delivered and the saddle it will sit in was also delivered from our local blacksmiths. The new rotator is the Prosistel PST110D. The old one was the 71 and was also broken in the same winds that killed the yagi. The big gear in the rotator was in several pieces.. hopefully this bigger one will do better.. I started repairing the elements of the beam, came up with the final solution and next weekend I am planning to do the same to the other two elements and also strengthening the 3 element sides that was not broken, just to be on the safe side. Here are some pics.. I put my shoe (EU size 45) just as a size comparison with the new big rotator which is heavy too 50kg/100lbs.

19 Oct

Workday Saturday 19 of October

Today myseld and Dag SMØKDG made some work at the station. We brought the 3 el 80m yagi down from 4m height where it was for a few weeks not to be in the way, so I can start repairing the broken elements. This week we also received a big telecom container fully equipped with an AXE telephone hub, all that will be torn out so we can finally build a decent workshop. There is really no such space at the station right now. A neighbour came over with his "tractor" and we managed to move the beast weighing 5,7 metric tonnes right now to its final position. I also made the last elements for the 5 element 12m yagi which i am building from old Hy-gain parts. It's fun to use old antennas just lighing around, make a new design with antenna modelling software and then making the build itself. I also already made a 5 element 17m meter yagi from an old hygain 205BA. Both antennas will go up on a tower behind the house before winter comes.. but we are very near now.. Also added a picture of the 30m half square that i put up 2 weeks ago, the horizontal part of the antenna is at 20m height, seems to perform quite well! Some more pics from today.

14 Oct

Station switching system design

My friend Mike SJ2W and me started discussing tiopics on station automation and integration over ten years ago, and Mike began forming a project called openASC, asc as in "Antenna Switch Controller". The initial demands would be to create some kind of device that would switch all TX and RX antennas. Turn rotators and monitor things such as output power and other data. The system should also be idiot proof! So in the heat of a contest battle you should not be able to break anything by running RF into "loose ends", ak.a get rid of the human factor. Mike already implemented the system at his site that he is building, you should follow the development there http://www.sj2w.se. I have spent thousands of hours myself over the last years and finally now I have most of the system up and running althogh some parts as rotator control etc.. is still to be built.

We have 4 operating positions at the contest station with an option of another 2 for a full Multi-Multi operation. When I designed the relay matrix itself for the antenna switching I decided that the following chriteria would apply. SO2R operation with high isolation between rigs. M/S and M/2 operations and possibility for M/M as well. To complete that it shoud also be possible to route WARC antennas into the system for DX chasing outside of contests. this is how the antenna switching matrix ended up:

openASC_RF_PathsTo simply describe the RF matrix 4 operating positions go into 9×2 switch boxes that connect Band Pass Filters for an actual band to the correct operating position. After the band pass filters signals are routed to an auto tune amplifier and to power splitters one for each band. The power splitters have 4 antenna inputs each. So each band can have 4 separate antenna systems to shoot RF into several directions at a time. the poer splitters are build with a 12.5 to 50 ohm transformer which makes it possible to combine up to 3 antenna systems on the actual band simultaneously. It will also be possible to add single bands amplifiers in the future, one for each band to avoid "tuning" during contests. Theese will be a project for the future.

12 Oct

Smoketest – new antenna switching system…

I've spent quite alot of time building a new antenna switching system over the last year which will be controlled by the openASC system developed by Mike SJ2W. Things came together neatly finally this weekend and now we are trying it out during the SAC SSB contest at the contest station. I will describe all parts more in detail later but will add a few shots of the two 19 inch racks that are holding all of the antenna switching units at the moment.

8 Oct

2×1 Switchbox

Last week I completed another switchbox for the large antenna switching array that I am building at the contest station. This unit consist of nine 2×1 switchcards that are all controlled individually.

8 Oct

Hello world!

After some time not blogging about Radio it’s time again.. So stay tuned for more =) 73 de Teemu SMØW

OJØR Market Reef

OJØR Market Reef

OJØR is my callsign during visits to the barren rock of Market Reef in the middle of the Baltic sea. [&hellip