Friday, April 5, 2019

Some more work at OL7M QTH...





We spent a few days at QTH. WX was great and we made some more work there. A few more  antennas are down and two new towers are waiting on the ground. I also rebuilt YU7EF dualband yagi for 4m and 6m. There are printed insulators made on my 3D printer. Design is from Dan OK1HRA, you can find it at RemoteQTH.com.

Also some more work on TOP band vertical and of yourse, on the garden and trees is done :)

Standa OK1CID run CQ WPX SSB as OK7W on 20m SO.

SWR 2m above the ground
New tower for BIG 40m Yagi and support for 80m one

Wednesday, March 20, 2019

Results of the Storm Eberhard...





There were a lot of storms... We lost TOP band vertical last year etc. But this was maybe the strongest one ever at OL7M QTH. Most of rotary antennas is shifted on the pipes... Usually, the strongest winds come from 300 deg. So "parking" position for the antenas is to NA. That Eberhard was different. It looks on W or SW wind. The antenns: 5el for 20m is shifted by 40 deg, 6el for 15m the same, bottom 6el for 15m has broken M8 screw on the linear motor and the two top antennas in the new stacks are demaged... So a lot of work on old antennas instead of new towers and antennas :( Thats live :)

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


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