Author Archives: mario

FM ATV and other activities

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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.

Video signal from DB0TUD from the sat-RX output shown on the scope
DB0TUD test picture shown on notebook screen via video grabber
tiny portable dish with modified PLL LNB (23.70625MHz crystal instead of 25MHz)

VUS Contest July 2019

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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.

DK7ZB Yagi for 2/70 and Quados for 23cm

2m Sporadic E 2019/07/02

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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.
I worked:
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:

pskreporter dh5ym coverage 20190702

Posted in VHF

Octagon OSLO TCXO Modification

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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.

http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html

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:

http://www.pg540.org/wiki/index.php/PLL_LNB

Back to the OSLO:

Modification:

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.

OSLO with TCXO mounted

PlutoSDR operation and some microwave beacon

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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).

Watch this video on YouTube.

Watch this video on YouTube.

Watch this video on YouTube.

OM Raachermaa

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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!

OM Raachermaa

4m access in DL / 13cm&6cm for class E

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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.

DUR 1810

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Working from home again. Only south direction 140-220°.It seems the participation in that direction was not that good. I need to put some antenna over the roof for 23cm at least.

Right side: yagies for 23/13cm, panel for 9cm. Left dish for 3cm. On the floor in the right corner dish for 6cm.

microwave rigs

 

Band QSOs Punkte AVG
1,3 GHz 5 266 53.2
2,3 GHz 7 178 25.4
3,4 GHz 1 8 8.0
5,7 GHz 1 8 8.0
10 GHz 1 8 8.0

Band 1,3 GHz

QSOs:             5
QSO-Punkte:       266
Punkte:           266
Durchschn. Pkt/QSO:   53.20
Durchschn. QSO-P/QSO: 53.20
Punkte/50 QSOs:     266
DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20181021 SSB 08.30 DH1DM 59 001 59 013 JO60VR 42 DH5YM
20181021 SSB 08.30 DG2DWL 59 002 59 013 JO60VR 42 DH5YM
20181021 SSB 08.32 DG5VL 59 003 59 002 JO61WA 14 DH5YM
20181021 SSB 08.48 DL4DTU 59 005 59 013 JO61TB 7 DH5YM
20181021 SSB 11.02 OK1FQK 59 006 59 021 JO70NA 156 DH5YM

Band 2,3 GHz

QSOs:             7
QSO-Punkte:       178
Punkte:           178
Durchschn. Pkt/QSO:   25.43
Durchschn. QSO-P/QSO: 25.43
Punkte/50 QSOs:     178

 

DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20181021 SSB 08.37 DO1UZ 59 001 59 004 JO60SX 18 DH5YM
20181021 SSB 08.50 DL4DTU 59 002 59 008 JO61TB 7 DH5YM
20181021 SSB 09.14 DO5UH 59 003 59 009 JO60WT 34 DH5YM
20181021 SSB 09.17 DG2DWL 59 004 59 008 JO60VR 42 DH5YM
20181021 SSB 09.17 DH1DM 59 005 59 008 JO60VR 42 DH5YM
20181021 FM 09.21 DM4SWL/P 59 006 59 009 JO61XA 19 DH5YM
20181021 FM 09.22 DM7MM 59 007 59 005 JO61UA 9 DH5YM

Band 3,4 GHz

QSOs:             1
QSO-Punkte:       8
Punkte:           8
Durchschn. Pkt/QSO:    8.00
Durchschn. QSO-P/QSO:  8.00
QSOs/Stunde:        1
Punkte/Stunde:      8
Punkte/50 QSOs:     8
DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20181021 SSB 08.53 DL4DTU 59 001 59 001 JO61TB 7 DH5YM

Band 5,7 GHz

QSOs:             1
QSO-Punkte:       8
Punkte:           8
Durchschn. Pkt/QSO:    8.00
Durchschn. QSO-P/QSO:  8.00
QSOs/Stunde:        1
Punkte/Stunde:      8
Punkte/50 QSOs:     8
DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20181021 SSB 08.54 DL4DTU 59 001 59 001 JO61TB 7 DH5YM

Band 10 GHz

QSOs:             1
QSO-Punkte:       8
Punkte:           8
Durchschn. Pkt/QSO:    8.00
Durchschn. QSO-P/QSO:  8.00
Punkte/50 QSOs:     8
DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20181021 SSB 09.44 DL4DTU 59 001 59 002 JO61TB 7 DH5YM

DUR September 2018

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DH5YM – DUR1809

Part time qrv from new QTH. Good takeoff direction south and nord. Only working direction south with very limited setup.
23cm 15W 14ele
13cm 1W ringfeed

Locator:: JO61UC
Band QSOs Points average
1,3 GHz 8 318 39.8
2,3 GHz 6 203 33.8

Band 1,3 GHz

Polar map for 1,3 GHz

DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20180916 SSB 09.11 DG0LFF 59 001 59 009 JO61VC 5 DH5YM
20180916 CW 09.19 OK1FJZ 599 002 559 011 JO60WD 107 DH5YM
20180916 SSB 09.23 DG5VL 55 003 45 010 JO61WA 14 DH5YM
20180916 SSB 09.24 OK1IEI 55 004 59 007 JO70EC 120 DH5YM
20180916 SSB 09.27 DH1DM 59 005 59 008 JO61TB 7 DH5YM
20180916 SSB 09.30 DG2DWL 59 006 59 025 JO60VR 42 DH5YM
20180916 FM 09.56 DG4VL 59 007 59 004 JO60VX 15 DH5YM
20180916 FM 10.27 DG1VT 59 008 59 001 JO61UC 0 DH5YM

 

Band 2,3 GHz

Polar map for 2,3 GHz

DATE MODE TIME CALLSIGN TX RX LOCATOR QRB OPERATOR REMARK
20180916 SSB 09.32 DO5UH 59 001 55 009 JO60ST 34 DH5YM
20180916 SSB 09.33 DG2DWL 59 002 59 012 JO60VR 42 DH5YM
20180916 SSB 09.35 DO1UZ/P 55 003 55 007 JO60RP 53 DH5YM
20180916 SSB 09.36 DL9NCI/P 55 004 55 007 JO60RP 53 DH5YM
20180916 SSB 09.58 DG4VL 59 005 59 002 JO60VX 15 DH5YM
20180916 FM 10.29 DG1VT 59 006 59 001 JO61UC 0 DH5YM