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Category Archives: Optical Communication
Another 43km Laser trial
During July V/U/SHF contest another 43km laser communication trial with DK5WMA.
Locations were JO60LK and JO60MT during the sunset.
Find a short video taken at my location here:
new laser ODX, 43km
During UHF/SHF Contest from JO60LK i had a new contact with DK5WMA in JO60MT.
The new distance is around 43km and a new ODX for me. The signals were really strong this time and it paid out to move
the RX PCB and the detector to metal boxes. No radio demodulation anymore and ufb AM QSO,
Later on it worked also with DO1CTL and during the night with DH0LS.
The picture shows my laser station and the green point from DK5WMA in the middle of the foto.
more laser experiments
Last weekend i did some few daylight laser experiments during the V/U/SHF contest. Unfortunately the contact to Marcel, DK5WMA was not possible due to much fog on Saturday evening. Our receivers are still not capable to deal with daylight. But we work on that.
DM7A team July Contest 2010 in JO60LK / 38km laser contact
last weekend i participated in the V/U/SHF contest within the DM7A contest group. We were qrv from JO60LK (mountain Fichtelberg). This time Murphy was definitively with us. Problems with the mains supply, defect power supplies, missing rotary controller, defect 23cm rig, no chance to get german UMTS network… Not even the german DVB-T network could be received from our location at the Small Fichtelberg. We had to view the soccer game DL-LU in OK TV ;)
Find some pictures here:
In the evening we tried Laser from Fichtelberg to the Dittersdorfer Hoehe near Chemnitz. The laser light from DK5WMA was visible immediately after switching on. The opposite direction worked as well after adjusting the direction on my side.
The signal was really strong but with heavy fast QSB due to the very humid air. We did the contact in CW. Find below a picture and a short video of my CQ loop that were taken by Marcel.
The following video shows how the laser of DK5WMA was seen in JO60LK. Of course the light was much brighter. The camera sensor seems not to take the green light very well. The flickering has its origin in the high air humidy and moving air because of some wind. The light was sent with constant amplitude at this moment.
Gallery of my Laser station
I created a small gallery that shows some pictures of my laser station. Find it here:
Laser station gallery
My first real world laser contact
Last weekend i participated in the UHF/SHF Contest within the DM7A team from JO60LK (Fichtelberg). The day’s before i completed my laser station. (Mechanical stuff for adjusting the laser diode and modifications for getting modulation working). A first test via reflektion at a house in 500m distance was promising. With Marcel DK5WMA a sked was arranged for saturday afternoon. I mounted the laser transceiver at the Fichtelberg. Marcel’s QTH was the Hirtstein in JO60OM. I adjusted the telescopic sight to the prominent wind wheels at the Hirtstein and switched on the laser. Marcel was able to see the beam immediately. How crazy. The sun was still above the horizont. The test from JO60OM into my direction did not work at first and we decided to wait for sunset. We tried again right after sunset and after some minor adjustments at Marcel’s side the twoway connection was working properly. Amazing to hear the voice over around 20km distance. We both took a photo of the red dot at the other side. Obviously DK5WMA’s camera is much better ;) See some photo’s below.
Two days before the next contest at least the mechanical work is almost finished. First tests looking promising. There are still problems with the modulation of the transmitter. Let’s hope for good wheather at the weekend.
Laser justification unit
In order to get the laser communication unit justified for the correct direction it is necessary to have the possibility for fine adjustment of horizontal and vertical angles. I made some progress in building a unit that can be mounted onto a tripod and will cary the laser transceiver in the future. Find some pictures attached below. It’s not finished yet but the horizontal adjustment works fine.