Es'hail-2 Transverter

  • Es’hail-2 Transverter

    I am allmost ready for working via Es’hail-2 Satellite. Both, my (first) Transverter and the Duoband-Feed for a 90 cm Offsetdish are ready to go.

    Uplink runs from 144 MHz to 2,4 GHz with max. 20 W output into the 2,4 GHz Patch of the Duoband-Feed. The Downlink runs from the 10 GHz-Horn into a Downconverter to 50 MHz IF for NB Operation (as well as 950 - 1200MHz IF for WB-Operation). Because there are less than 2 m between the Antenna and the Transverter, I let the Downconverter for lower Temperatur-/Frequency-drift in the Transverter-Box.

    73! Kleiner Peter, DJ7GP

  • Hi Iain,

    thanks for your interest in my Duoband-Feed for Es’hail-2. I first talk about that feed at 38. GHz-Tagung in Dorsten on 21. Febr. 2015 (Tagungsband) and at UKW-Tagung in Weinheim on 12. Sept. 2015 (Skriptum der Vorträge). It was also published in „Funkamateur“ 2016, Heft 5 u. 6. Some more details for practice you can find at…_dj7gp_duobandantenne.pdf. There is also a tranlation to france language by Pierre Marie, F5XG, at…e-duo-bande-2-4ghz-10ghz/

    If you need a copy of any of my bublications, please let me know.

    Hope I could help you!

    kleiner Peter, DJ7GP

  • Do you think it would be feasible to construct a 13cm feed that would fit around a standard TV LNB? I will use my TV dish with a PLL LNB for receive (it is mounted on a H-to-H motor) and I currently have an LNB that has (with the plastic removed) a neck of 20mm and a horn of 50mm diameter. That could be a bit large to accomodate your 13cm feed, isn't it? Another difficulty is that the horn cannot be removed so it will be tricky to get the 13cm feed fitted around the neck.

  • Hi Rob,

    oooh boy... yes I do some experiments with a Patch around an LNB (picture 1)… and I don’t success! But it should work, when you remove the plastic enclosure and mount the Patch on the neck of the LNB. I agree, it should be a little bit tricky. But what about the 50 mm Horn? I really don’t know, maybe it works like a director for the Patch???

    I also do some experiments with a Helix around the LNB (picture 2). The Helix works quite well. But the 10 GHz Horn does not like it, because of the Helix in front of the Horns mouth.

    What we need is a slim LNB (picture 3) with a PLL (and TCXO, OCXO or an external referenz). But until now I could not find such an LNB.

    Can somebody help?

    73! Kleiner Peter, DJ7GP

  • Peter, an alternative could be to mill off the horn part of
    the LNB and use 24/22 Ms or Cu pipe/tube in conjunction
    with your patch feed.

    Thus omitting the SMA-connector and bottom plate in your
    current 10 GHz-contraption.

  • What we need is a slim LNB (picture 3) with a PLL (and TCXO, OCXO or an external referenz). But until now I could not find such an LNB.

    It looks like the technology for LNBs has changed. I ordered a couple of PLL LNBs in China and received a box that was not even mentioning PLL on it. I mailed back the sender that I got an ordinary LNB while the website said "PLL" and the reply was that it really was PLL. I opened one and he is right, it has a 25 MHz crystal and no DRO.

    So maybe I try to order some slim LNBs and see if they happen to be PLL as well. It could well be that the cost for manufacturing a PLL LNB is now below a DRO type and they just silently switched over. My LNBs were only 7 euro each...

  • I´ve prepared a PLL LNB. I exchanged the original crystal quartz with a custom crystal quartz manufactured by Firma Quartz Technik, Daun / Eiffel. f = 23.58974 MHz.

    LOF/L now 9,200 GHz. Test with wideband BADR signal is successful.

    I try to receive the narrowband downlink with my FT-736 1,2 GHz modul on the downmixed 1289,8 MHz ZF frequency.

  • Is it also a bit more stable than the standard crystal?

    I have tested with an unmodified standard PLL LNB and in steady weather and not around sunrise/sunset it is bearable, but realistically you'll always have to have your hand on the dial for SSB.

    Of course it is possible to lock it to a GPS reference, but I also consider some form of automatic locking (at the IF frequency) to the beacon.

  • Yes, you are right. These are also my fears.

    I´ve bought the best available in terms of temperature and frequency stability. Is it enough? We will see...

    In the worst case, I have to improve with a heating pill .....

  • See my solution:

    Yes it should be possible to solve it using locking, however what we need (in the software) is some possibility to lock on the beacon and then tune to another frequency where the locking that tracks the beacon also makes the tuned qrg track in the same way. I don't think that is already available in one of the SDR programs, but it probably will be in the future when lots of people face this issue and some competent SDR programmer picks it up.

  • A (very) good crystal ('especially cut for you') has a precision in the range of
    0.5 ppm (variation in temperature(s) not included).

    So, for these PLL-LNB's with a crystal of (mostly) either 25 or 27 MHz, let's take

    26 MHz as mean frequency, the frequency will be off (in worst case)
    0.5 * 26 --> +/- 13 Hz (a range of 26 Hz)

    The LNB 1st LO is (often) 9750 MHz, divided by 26 MHz = 375 * 13 = +/- 4.875,

    say ... +/- 5 kHz off and/or 'wobbly' in worst cases (over time).

    So, my opinion is that a single crystal will not be sufficient for narrow band
    operation. (Your .. all .. mileage(s) may (of course) vary)


    Ich warte auf den AMSAT-DL-Transverter & Konverter von Achim.