Tuesday, March 12, 2019

Wind! We hate you! :(

There are the results of the whirlwind called Eberhard...

The TOP two antennas in our new stack for 15/20m are for RIP = Rust in Peace (OK2RZ JdC).
Also our fireplace and 6 el Yagi for 10m...

Saturday, March 9, 2019

10 GHz LNB with PLL and TCXO, Bias Tee, part II.

   Very simply modification of LNB with PLL and 25 MHz X-tal. With 1 ppm TCXO there is nice 10 GHz RX for tropo and satellite. You need only some SDR receiver.


   Bias tee board allows you to supply LNB over the coax. It also includes high current and voltage protections as well the variable ATT. You can easily set "gain" of LNB as you need. Recommended power supply is +12 V and some 100 mA.

More info about TCXO modification is there...

You can ask for price on my email: honza at ok2zaw.com or shop on ebay.

Do not forget to visit our OpenWeb RX on 10 GHz:

Saturday, February 23, 2019

Es Hail 2 - Oscar 100 satellite OpenWeb RX

It looks that new Es Hail 2 - Oscar 100 Satellite will be very popular. Big advantage is that this is the geostationary satellite! You can fine more here. It has got 10GHz down link. Well, years ago it could be a problem, but now you can buy cheap LNB for very small money! You can use TCXO for better stability and very simply RX is done (it is link)!

After 10GHz tropo OpenWeb RX I made also Es Hail 2 one:

 RTL-SDR for Es Hail 2 and another 2 RX for tropo 10GHz and 2m APRS:

 Future of 2,4GHz Uplink

10GHz LNB with PLL and TCXO

   Satellite LNB is very cheap source of 10GHz converter. Especially now, when the classic DRO was replaced by the PLL with X-tal. I played with 10GHz tropo web SDR RX. It works great. There are two LNBs with one TCXO. You can see more here. As IF RX there is nice RTL-SDR toy. I do have TCXO for that as well and done some modification for better stability. You can find more here. 

   There are two (?) X-tal frequencies in the LNB. I do have one with 25MHz but I have seen one also with 27MHz.  LNB with the original X-tal can be 100kHz shifted. After heating it is stable, but not as well as with TCXO. There is standart X-tal so you need to use some SDR for the IF frequency. 

For example, the 25MHz is multiplied by 390 to 9750MHz. If you calc IF then it is:

10 368MHz - 9750MHz = 618MHz

For Es Hail 2 it is:

10 489MHz - 9750MHz = 739MHz

I ordered also another two TCXOs for 70cm IF. Than:

10 386MHz to 432MHz is 25,476923MHz
10 489MHz to 432MHz is 25,787179MHz

But I ordered 1ppm TCXO, so there is some mistake done by the production:

This is not a problem for SDR RX where you can do some calibration. But for classic 70cm RX you do have some frequency offset mistake :( 

Do not forger, any small mistake is multiplied by 390 !!! So 10Hz is finally 3,9kHz !

Almost right frequency
21Hz mistake means 8kHz on IF (RF)

Rebuilding the LNB. There is a lot of different LNBs... In my one I remove original X-tal and add TCXO. There is close V-stab what is and is not good. It is easy to connect power supply to TCXO on the other hand, this stabiliser produces heat... There are more ways, I used 1k8 resistor from 6V to TCXO. It is 3V3 one. Or you can use 3V3 zener diode and 680 ohm resistor. Do not forget to 100nF capacitor or more.

With zener diode

TCXO description

Voltage bias tee. There is a PCB designed to do voltage supply bias to LNB over the coax, with some protections and also variable ATT. LNB + RTL-SDR can have too high gain, so you can set it as high as you need!

 I can offer you TCXO, rebuilded LNB and bias tee. If you are interested, please contact me at:

honza at ok2zaw . com


Wednesday, February 20, 2019

ARRL CW 2019 as OL7M in M/M

We have decided to dedicate this contest in a memory of our good friend and great contester Dave, OK1RK (ex OK1AUT) who suddenly passed away a month ago at his only 47 years…
R.I.P. Dave. We really miss you Dave!

After the last weekend where the CONDX were poor, we really enjoyed one of the best CONDX on 160m and 80m to US for last 10 years in the ARRL contests. Especialy the first night was amazing. We made enough of West coast stations. Also nice surprise was the opening at 21 MHz.

All of that wouldn´t be possible without our technical guru Jan, OK2ZAW. Everything worked perfectly. Only 8 el wire yagi for 40m burnt out . So we had to use 2 element MOXON.

Even that we knew we can not compete with the stations in the west and south of the Europe,  we enjoyed the contest and team spirit for whole weekend a lot. The weather in February was unexpectedly great -  clear sky, sunny days without wind with temperature about 15 C, so what can be better than the first BBQ of the year, hi.

BTW it is confirmed again -  the US stations’ pile-ups are the best in the world!

Thanks to all for the QSOs  and see you next time!

Pavel OK1MU on behalf OL7M gang

Some mor HP power for contesters :)
Tom OK1IC and Pavel OK1MU. And your supervisor Marous.

Tuesday, February 12, 2019


   I love RTTY :) What more, a year ago we have tried the SO2R 2BSIQ in the BARTG contest. It was a lot of fun! Than Pavel OK1MU as OK6W won the EU in the CQ WPX RTTY 2018 (link) and new way of the single operator contesting started ...

   I wanted to test some new HW, also our new STACK for 20m (link) and enjoyed 2BSIQ contesting in the big contest. All the HW worked great. A lot of new ideas and more work have to be done anyway.

   DX conditions were not so good. The 80m was higher than average, I played on the WC almost all night, also some W6, W7 are in the log. On the other hand, the 40m was really bad. I had less than half of QSOs on 40 than on 80m after the first night... I was not able to have good RUN on 40m during all contest :( The 20m was also not as good as it could be, but our new stack helped a lot! 

   I logged 562 USA, 48 VE, 137 JA and 32 YB.

There were also opening on 15m with the great signal from CT3, but I also easily made the only NA station - W3GH. Thare are no skimmers, so no more spots in RBN :(

   See you next weekend in ARRL CW as OL7M in multi.

80m: 4SQ + dipole
40m: 8el wire Yagi to NA + 2el Moxon
20m: 5/5 stack + 5/5 NEW design stack to NA + 2 x HB9CV (SA,AF)
15m: 6/6
6x beverage
New IP beverage switching by RemoteQTH.com

IC-7800 + IC-7600


RBN at WA7LNW on 80m