Receiving system not based on Octagon LNB

  • Hi DB8TF yes your sw drift corr is a cool idea. However you are dependent on the cw beacon always being available ( they have turned it off one time already as far as I know).


    Many times people also transmit (almost) on top of the cw beacon to check their power level and frequency etc. This can cause problems with such a scheme if the FFT peak selector algorithm of yours locks onto the wrong FFT bin because the guy sending almost ontop of the beacon is stronger etc etc etc


    (I took a quick look at your .py code. Cool concept for sure). Also not always do we have the possibility for cat control of the receiver.


    That's why I at least for now would like a hw based approach.

  • This one is with PLL and also known to be very stable.. usually enough for normal SSB..


    https://www.pollin.de/p/univer…edia-gm-201-0-1-db-571751


    Some people have also modified it for TCXO..


    There seems to be a GM-201+ (plus) Version and also a Twin LNB GM202+ (plus) as successor, it might also have PLL.. needs to be confirmed.

    Peter Gülzow | DB2OS | AMSAT-DL member since 1983 | JO42VG

  • Hello Mike ,


    my reference is either the lower engineering beacon from EH2 or currently i am using the telemetry from Astra 2C (i think). So completely independend from the P4A transponder ;)


    The .py is not from me, i am no software engineer ;)


    Vy73 DB8TF

  • DB8TF yes using Astra at 28.2 as a reference may be a more viable solution. However I need a stable clock source for transverters, converters, radios etc so I will use a GPSDO or very good OCXO in any cas I think.


    QSL that the .py is not your code, but the idea is a good one as long as you always have a pc or controller that can execute the servo loop at all times and something solid to lock onto.

  • I'm using GM-201 stable enough to made 120+QSO without change anything..But temperature outside not change so much....maybe drift will be at summer time but is worth for low price.


    The same IC was used in DG0VE converter I think. TFF10xx by NXP application notes

    are on web. Inside is 25MHZ quartz, but in AN you can find that 24MHz is also ok to change the IF frequency....

  • Hi I'm building up a Station.I'm able to found on local store a LNB GTS40M. The box claim 'Powered with PLL technology'.I will test is soon.
    Anyone have some experience with this LNB ?.

    See you soon on satellite.


    David

    IW5BNL

  • Hallo...


    i got an similar model today...


    https://www.ebay.de/itm/AX-Bla…a66b7f:g:WyQAAOSwg31ahPWo


    2 x RDA3565S , one crystal (27MHz??) maybe below the PCB... no seen if open...


    GOOD RECEPTION on 26 EAST BADR4 11996 > 9dB ...a bit more sig then the OTSLO 1208/1301


    look nice at first sight...


    EDIT:

    Testet the unmodified LNB on 10492 H (ES Hail2) ,11196 H and 12168V (BADR4)

    nice signal levels on my 85cm Dish... 0.2-0.4dB better then the old OTSLO 1208/1301


    OK for the MONEY...!


    73 de dg0opk

  • EDIT: This LNB wobbles worse than the GM201 ! Don't buy it!


    Hello OMs,


    today arrived the HD Line Black Premium LNB.


    And it is with 27MHz crystal and the RDA 3565ES PLL IC ;)


    No need to buy overpriced Octagons anymore. 17€ from Amazon, delivered from France to DL in 4 Days.


    And it comes with 2 "golden" F-connectors.


    vy73 DB8TF

  • Maybe with D75F or ext Ref it works fine?


    I also don't understand why it wobbles but i have installed a small dish for testing various LNBs on the balcony and so i can quickly compare LNBs.


    After the HD Line BP2 i installed a "old" Octagon and this works perfect.


    CW Bacon crystal clear sound (clearly with drift as the LNB warms up).


    Big difference between those LNBs.


    Maybe someone with the right measuring equipment could determine why the LO on some LNBs is wobbling and on others not?. I would do it myself but my spectrum analyzer only works to 2,6GHz ;(


    73 DB8TF

  • I had an idea this morning. The HD-Line-LNB has 2 user ports for 2 receivers but only ONE crystal oscillator for both. Is that why it wobbles when you leave a port open? What happens, when you connect a sat receiver or satfinder on the other port ? How many ports has your old Octagon ?


    "Auf Deine Antwort bin ich jetzt aber gespannt!"

  • Greetings all,


    I just picked up an LNB for testing, and completely disassembled + reassembled it.
    This one is currently sold at "Expert" (and possibly many other stores) in Germany:


    Vivanco "STL US3K-N 44179 Universal Single LNB". Cost less than 10 Euro.

    Contains a 25 MHz PLL (the crystal is on the BACKSIDE of the PCB, towards the waveguide). There is NO frontend-selection before the PHEMTs - only a few millimeters between the gates and the two probes (for H+V) coupling into the waveguide.

    Even without adding a controlled heater for the crystal, it's even better (less drift) than my older "HD-Profi Single LNB Gold" (which had a 27 MHz crystal, but doesn't seem to be available anymore).

    In contrast to a "Schwaiger Single LNB" / "LNB 1" (from "Marktkauf") which also has a 25 MHz PLL and appears "useable", the Vivanco is much easier to disassemble (just in case someone wants to replace the crystal with an OXCO). The "Schwaiger LNB 1" has the F-connector mounted on the cover, and when disassembling it, the first thing that happened was that I ripped the IF center pin out of the board. Duh. No problem with the Vivanco LNB (STL US3K-N), because the F-connector is on the opposite side of the cover.


    I can post a few photos from the interior if anyone is interested (not sure about size limits in attachments on this forum)


    73,

    Wolfgang "Wolf" DL4YHF

    - hope to meet you in Bochum again, or in Friedrichshafen this year -

  • Hope the 400 MByte attachment gets through..

    here is a photo of the Vivanco "STL US3K-N 44719".

    The 25 MHz crystal is, as already mentioned, on the lower side of the PCB, but after opening the lid (secured with 5 screws), it's easy to see which traces lead to the crystal, and instead of removing the crystal, those traces could easily be cut.


    73,

    Wolf .

    Edited once, last by dl4yhf: emphasis on the number "44719", as written on the cardboad box (in the background of the photo). That's the tiny "Universal Single LNB". ().