• So, i have to choose between this 2 tcxo LNB's


    as already asked, it is important what you intend to receive and what the further receiver chain will look like.

    On the one hand, the frequency stability of the LNB depends on the operating mode, and on the other hand, the IF. If a standard RX follows, an IF on 435 MHz may make sense. If strong mobile radio signals are present in the LTE range, an IF around 735 MHz (25 MHz TCXO) can be disturbed.

    I see the antenna is 1.8m, so I guess DATV is also an option?

    Then an LNB with simultaneous horizontal and vertical output would be good.

    Without more precise information, an LNB cannot be recommended.

    73 de Robert, DD4YR

  • Right.

    AFAIK, the bullseye lnb features a TCXO with 2ppm , while qro.cz claims 1ppm. You need to make or buy a bias T from an outside source when you opt for bullseye. The qro.cz comes with one included. Bullseye features a 25MHz output you only need when you want to reference a subsequent sdr like pluto and is exposed to changing temperatures and therefore might drift anyway. That might make it unusable as a reference for a sdr, but that's just my opinion . Others may prove me wrong. Personally, i'd go for qro.cz. You can get an adapter for your poty from them also.

    Hope that helps.


  • Thanks Robert and Martin.

    Yes, it make sense to explain the whole (future) plans:


    1st i just will try SSB and small-band ATV ( SGLABS 20 watt amplifier already ordered). Maybe a preamp is not necessary.

    I will use the LIMESDR USB (ext.clock available on it) but maybe the Adalm-Pluto is an option but that is the B version so no ext clock.

    Also i have the minitiouner express for receive. So enough options to play with. :)

    I think the LIMESDR USB will be it.


    Next step would be wide-band ATV. I have a full spectrian SSPA from pyrjoseph but need some work to complete.

    Therefore i need a Poty with N connector for that high power when i choose a Poty.

    I'm not sure what would be the best for these 2 situations. Poty or helical for TX.


    Also at some far future moment i will use these dish for other birds and eventually EME but that's a complete different story.

    Regarding which TCXO LNB:

    Buying a bias T from a other source is not big deal but the TCXO with only 1 ppm (i overlook that) is more important than the frequency offset because sdr console will deal with that. So would also go for the qro.cz (wiht helical or Poty?)

    I also could change the LNB head if desirable for a specific mode.

    So that's my whole story.

    I will be happy for any advise on this.

    Thanks again, Ben 73

  • Hallo,

    I was asked sometimes, which LNBs with PLL are available. The market seems to change quickly. That's why, I and others too would appreciate some informations about actual LNBs with PLL. From my point of view so called slim line or rocket types are easy to modify with an uplink transmit antenna. No matter if the antenna is a poty or Helix. If there is a 10 GHz waveguide, both types can be sticked together with a socket to the waveguide. Both antennas match with the focus point. The following link shows a picture.

    The sat-dealers don't know what is inside the LNBs. That's a pity. I would like to collect some infos about suitable LNBs to give it to others who are starting with a sat-station.


  • The sat-dealers don't know what is inside the LNBs. That's a pity.

    Take a 12V battery, connect it to a unknown LNB and place a scanner near searching 25 & 27MHz .

    If it is a PLL LNB you will find the 25 or 27MHz signal. If there is no signal its an DRO LNB.

    I have checked many LNBs that way in our local stores "OBI, Globus Baumarkt/Euronics/Expert..." without any problems by the staff ;)

    73s DB8TF

  • Hallo,

    good idea, thanks. Are there any further results, we can use to help the beginners?

    Octagon offers an interesting type, it's called "Whispy". It looks like, there is a plastic lense. Until now no answer to my email I wrote to OCTAGON.


  • Hallo,

    I received an answer from Octagon, the Whispy-Series do not use a PLL and are obsolet. From my point of view such PLL-LNBs can be used even with a horn. If there is some waveguide after removing the horn to carry the transmit antenna, it will work. Probably there is some trouble with the original clamps so make a new one. Especially the the plug of the transmit cable collides with the clamp. Use SMA instead of N. If the PLL is not too far away from 9750 MHz leave the crystal untouched. Check the real frequency of the PSK-Beacon and tell the the difference to the Console . It will lock and be stable.