Last days we have strong tropo conditions. Currently i run a Openwebrx with FT8 monitor on 2m and although i only use a small vertical monopole the maximum distance of reports are >800km. Some 2m FM relais from Hamburg was audible very loud. The 70cm band was full of repeaters (i think most of the signals were DMR). This evening i gave 70cm a try. I was surprised to hear LA1UHG beacon from JO59FB (>900km). Other beacons heard: DB0VC (JO45), OZ7IGY, OZ5SHF, DM0UB. I worked SM7LCD in JO86 over 600km with only 30W and Quados-6 antenna.
Over the past months there was quite some activity here and there but i found no time to document it. For vacation i took my FT-857 and the small duoband yagi and tried some FT8 in the evenings. I also tried some meteor scatter on 2m here and there. In November i found some time to participate in the Marconi contest with the DM7A team from JO60OM which resulted in a 3rd place in DL as multi-Op station. Some small activity was to collect some equipment for watching the local analog TV repeater which was reactivated during the year. After months of searching i found a nice portable FM satellite receiver. The repeater transmits on 10200MHz. With a normal satellite LNB with 9750MHz LO this will be far outside the tunable IF of the receiver. From previous experiments i had some cheap PLL LNB with 25MHz crystal. From previous experiments i found that it was not that usable for narrow band QO-100 acitivities as the 27MHz referenced Octagon LNBs but i knew that the PLL locked down to a 23.3MHz reference. So i ordered some 23.70625MHz crystals and exchanged it. With this crystal 10200MHz is converted to about 950MHz which is just at the lower end of the sat-IF range (the receiver tunes down to 900MHz). From the roof window i can now receive the DB0TUD ATV repeater 10GHz output. I do not know the frequency response of the LNB yet. Most probably the LNB is not very sensitive since the frequency is quite low compared to the satellite band. For some reason i broke my old DVB receivers AV input. So i used a cheap USB video grabber card to watch the video.
Originally i planned to join some contest operation on the hill. On short notice i had to withdraw because my time did not allow. So i used some time in the night (when the kids are sleeping) and a little time Sunday noon to make some QSO from home. This time i operated a DK7ZB dual band yagi for 2m and 70cm. It is a 4ele on 2m and a 5ele on 70cm. The next highlight was that i was able to turn the antenna automatically and completely do remote operation from anywhere in the flat (at least for 2m). Many thanks to the guys from IQ5NN which where so patient to complete the ODX QSO with my tiny 50W. I also heard IO2V and another I station but was not able to do the QSO. In the end it was 37QSO and almost 10k points of cherry picking. 10 QSO on 70cm were done with the 20W from my good old FT-857D. 23cm i did not plan to do but the antenna was still on screwed to the mast, so i did 5 QSO. One fast local QSO on 13cm finally. 9, 6 and 3 cm were not activated because of no time.
I have to say that i cannot install fixed antennas. So its always a portable like style with small antennas that fit through the roof window or just point out there. And this kind of operation is only possible if it does not rain and it is not too cold.
Today i managed to catch a tiny bit of the 2m sporadic E opening. Although i only have a tiny setup with 50W into a mobile antenna on the rooftop i was able to work 3 stations in soutch EA. The cloud was above HB9 and gave some good signals from EA.
EA3DBJ SSB JN00
EC5CIA FT8 IM99
EB5AL FT8 JN00
This was how the MUF map from dxmaps.com did look like:
2m sporadic E map (dxmaps) 20190702
And in those locations i was heard during the evening:
I have an older OSLO LNB which, was my spare for the websdr. Now i want to use it for QO-100. To improve the temperature stability a TCXO was fitted in place of the original crystal. Find some pictures below.
The type is a TXC 7N-26.000MBP-T from TXC. It works from 2.7 to 5.5V. Luckily the LNB works with 5V from an 7805 regulator. The TCXO was supplied by Michael DG0OPK. He suggested this type and already modified a OTLSO some years ago.
Some warning: This might not apply to current types of the Octagon LNBs. As far as i know you will likely get a 25MHz crystal version if you try to buy one. It will not be possible to use the 25MHz LNB with a lower reference frequency.
LNB with NXP TFF1017 IC could be an alternative as far as i know. I have no experience with this type. Here is some reference:
First i removed the crystal. It is necessary to use hot air because otherwise the pads might be damaged. But they are still needed. Also the 0 Ohm resistor over the two traces that go between the two pads needs to be removed. The trace connected to the former crystal pad closer to the RF section needs to be disconnected. This crystal input will be left unconnected.
OSLO LNB with crystal removed
Now a insulated copper wire can be connected to the pad of the former 0 ohm resistor that leads to the converter IC. The capacitor to ground at the crystal pad close to the 7805 regulator needs to be replaced by a short. The other crystal capacitor should be replaced by 100nF.
OSLO prepared for mounting TCXO
Now the TCXO can be soldered. It is important to avoid shorts of the pins of the TCXO towards the PCB. I soldered the TCXO slightly elevated. It is important to keep distance from the border of the PCB because the cap of the LNB still needs to be mounted. The insulated copper wire can be connected to the output of the oscillator which is pin 5 (right of the row of capacitors). The pad with the remaining capacitor towards ground needs to be connected to the output of the 5V regulator. It is the regulator pin with the 0 ohm resistor.
The pins of the TCXO are assigned as: 9=VCC (left of the capacitors), 4=GND, 5=Output.
Below i add some short videos i made. The first two show transmit and receive operation of the PlutoSDR in the 6cm amateur band. I used the great sdrangel software. The opposite side is my normal 6cm rig consisting of a FT-817 and a DB6NT transverter.
The third video shows 3 of the DM0TUD microwave beacons that are located close to my home. It is from right to left: 13cm (FT-290), 3cm (FT-790R2), 9cm (FT-817).
This is an traditional figure from the Erzgebirge. OM seems to do VHF contesting which is also popular there ;) But maybe not only the OM is smoking but the transceiver as Wellness eventually. Merry Christmas to all of you!
German BNetzA released notifications 414/2018 and 415/2018. Those extend the permission for class E operators to work in the 13 and 6cm band as well give a new permission for 4m band access in DL. On 4m class A will be allowed from now on to Dec.31 2019 to work between .150 and .200 with 25W ERP max.