Posts by DL5RDI


    You have several possibilities:

    1. switch PTT via the 3,5mm plug

    2. set the jumper inside to switch to TX via +12V on the coax

    3. HF-Vox - is active any time (to protect the transverter of TXing into the RX part ;-) )

    But there is a manual that can be downloaded from Hrisijans web site where all the above mentioned points are explained.

    73 de Johannes


    sieht so aus als hätte er für jeden Anschluß ein eingenes PLL-IC. Der Eingang für die LO-Frequenz (hier original 27 MHZ) sind je PIN 19 und 20 (d.h. vom "Markierungspunkt" aus der am meisten rechts gelegene Pin in der "oberen" Reihe und der links daneben.)


    in welcher Art möchtest Du das LNB modifizieren ? Speisung der LO-QRG über eine F-Buchse und ZF über die andere Buchse (das sollte das Einfachste sein) oder ZF über beide F-Buchsen und zusätzlich über eine Speisung mit LO ?

    @ DB8TF

    Du must nicht unbedingt die Leiterbahnen vom Quarz her verfolgen. Wenn Du das Datenblatt des PLL-IC hast kannst Du die "Verfolgung" von da aus aufnehmen und musst ggf, die Platine garnicht anheben/ausbauen (habe ich beim Umbau meines Venton-LNB so gemacht - da ist der Quarz auch auf der "Unterseite" der Platine ;-) )

    Servus Johannes

    I don't press PTT. In RX mode there is enough signal at the 24th harmonic.

    Beware that some (older versions) go into an alternating 'on off mode', but that can be circumvened (for a while) by pressing the menu button.

    ...because of this I push the PTT ;-)

    ..and if you have not a BAOFENG the 24th harmonic (while pushing the PTT) works also with any other 70 cm TX :-)

    73 de Johannes


    Hello Heiner,

    just got a Venton singel LNB and modified it for external reference via the IF-cable.

    What ist the part (clamp) called which you use to mount the LNB to the POTY (the name that I can ask for in the lokal "Baumarkt")

    73 de Johannes


    like Heiner (DD0KP) said the easiest way is to take the 24th harmonic of a 70cm signal (e.g. from an handheld). 437.075 gives you a 10GHz signal at the upper beacon.

    Just hold the handheld close to the LNB and push PTT ;-)

    (If you have a BAOFENG UV5R you will see also the "processor-spikes" few kHz lower than the beacon frequency)

    73 de Johannes


    I just REF-locked my updated MKU UP 2424A (now "B" ;-) ). Seems that the 10 MHz signal has to have a certain level to lock. With my leo bodnar GPSDO in the lowest sigal level setting it locks about 80% of the time; with the second lowest level it locks 100%.

    (I connected a small coax with the free "mini-coax" connector - on the board from were already two coax cables go into the other module and mounted a SMA-jack in the rear (same position as in 2424B) of the upconverter.)

    73 de johannes


    I now have my poty ready with a very nice RL-curve and it works very well.

    Now I wonder if anyone has experience with covering the POTY with a thin coat of (non conducting) paint to protect it against corrsion.

    Is the influence of the covering paint significant ?

    I ask, because I tuned my POTY with a piece of dielectric material (thanks to Pavel OK1PHU), thus I suggest that there is an influence even of a thin layer of any material.

    73 de Johannes


    Hallo Thomas,

    wenn ich es richtig verstanden habe benötigst Du das Kabel vom LNB zum Empfangsmischer ?

    Da werden keine 10GHz übertragen, sondern für Dich interessant ca. 750MHz und das mit einem Pegel, dass Du nach 20m Kabel immer noch ein Dämpfungsglied benötigst ;-). Das wichtigste ist eine hohe Schirmung des Kabels um evtl Einstrahlungen vom Mobilfunk (LTE...) zu vermeiden.

    Sollte ich etwas falsch verstanden haben, dann sorry.

    Das von Dir gezeigte Kabel ist als Fertigprodukt OK. Deutlich billiger wäre es selber 2 F Stecker auf ein gutes Koaxkabel passender Länge zu schrauben ;-)

    Servus Johannes


    rather feed the TV-dish with a patch feed than with a helix.

    Today I tested the 5 turn Helix from WINKLER (which I adjusted for 2400 MHz, because from factory it was horrible) as a feed against the POTY-feed. The difference measured via QO-100 was 3dB in favorit for the patch. (I tested with a 1,2m offset dish)

    73 de Johannes

    On6zg Hello Jan, in my PA there are only a few parts for matching the output

    (see image below), but no real filtering. Maybe the matching can be optimised

    for 2400 MHz (but shouldn't be to bad in original because it's the lower end

    of WLAN frequencies.

    (A friend of mine even measured 35dBm in an unmodified PA of this type).

    73 de Johannes

    Hello Wolfgang,

    thank you for the numbers you show in your test.

    Did you adjust the position of the POTY (distance to the dish). In your pictures the "entry" of the waveguide seem to be very close to the dish compared to "entry" of a normal LNB.

    Your figures show that the Nylon lense is 2dB worse than even no lens at all. That's a point to think about.

    73 de Johannes