Posts by DG9BFC

    Ein Wilkinson Teiler hat aber keine 90 Grad auf einem Zweig!!!

    zum Zusammenschalten braucht man einen 90 grad Splitter/Combiner am Ein- Und Ausgang!

    und wenn jeder Block selbst aus 2 Stufen mit 90 grad Splittern besteht (was hier der Fall ist) sollte jeder Block mit einem Zirkulator abgeschlossen werden, bevor man zum Combiner geht ... damit der eine Verstärkerblock den anderen " nicht sieht"



    sg labs pa
    modded lnb
    middle beacon
    adalm pluto
    poty feed
    80cm offset dish
    upper beacon
    Bu 500 Upconverter
    sdr console
    1m cf dish
    lower beacon
    amsat dl upconverter
    dx patrol upconverter
    wifi grid antenna
    india morning net
    leo bodnar gpsdo

    problem is that you installed the genuine fw from AD (0.38) ... that is "too new" to work with the datv fw by evariste

    in older installs i used fw31 from analog devices and then installed 2103 from evariste (quite similar to the 0303 version)

    now i am using the very new fw from evariste (0.3-31) that does not has the web page anymore but can be controlled from "node red" gui

    fw can be found here

    beta – Google Drive

    also read the wiki

    PlutoSDR softwares using custom hdl design. Contribute to F5OEO/pluto-ori-ps development by creating an account on GitHub.

    da kann man sein Signal schön verhunzen wenn man diesenTx Filter FALSCH einstellt .. genau dann entstehen diese Geistersignale

    am besten auf 50% stehen lassen und NICHT weiter reduzieren ... ja ich weiss durch Reduzieren bekommt man mehr Ausgangspegel (aber eben auch Geistersignale die man nicht will) ... je nach eingestellter Bandbreite im Pluto (576 oder 768 oder was auch immer) kann man durch reduzieren dieses Tx Filters mehr Ausgangsleistung erzeugen .. aber wenn man das falsch einstellt gibt es unerwünschte Nebenaussendungen

    je nach Bandbreite gibt es da werte die gut fuktionieren und einstellungen mit fürchterlichen Werten

    wenn man nicht genau weiss wie man das einstellt FINGER WEG (also 50% default belassen)

    meist braucht man diesen erhöhten Pegel nicht und die default Werte passen

    hier findeest du die Fw von Evariste

    damit funktioniert die Ptt steuerung

    im Pluto ein 5V Relas verbauern and GPO 0 und 1

    Am besten du nimmst gleich ein 2 poliges Relais und schaltest mit einem Kontakt die Vorstufe und mit dem anderen Kontakt die Ptt von der SG-Lab Pa

    dann ist beim Booten die Vorstufe aus und die Vox der Sg-Lab pa spricht nicht an

    obwohl die Pa eine Vox hat IMMER auch die PTT benutzen ... sonst kann man zB kein FT8 mit geringem Pegel machen (weil die Vox nicht anspringt bei kleinem Pegel)

    it was me who brough mike to the idea of the square with the cut corners (i have no lathe so peters feed was not easy to reproduce on the kitchen table) .. i calculated in sonnet lite and mike calculated in cst studio ... and end result was near identical

    rest is history

    difficult to build and tune ?? yes a bit ... but when exactly made shows a good circular pattern and is near spot on

    fifth harmonic is 12ghz (5x2.4) and can desense (with lower power) or kill the lnbs first transistor stage

    and 12 ghz is easy travvelling inside the waveguide (its build for 11 to 12ghz .. not?!)

    an overdriven and clipping amp produces higher fifth overtone

    so stay low in power and stay linear (plus a lowpass filter inside or behind amp)

    that lowers the signal on 12ghz that otherwise... see above

    with a better lens and a better position you can improve your rx and tx signal

    either hack away from a commercial rocket lnd or print your own (drop me a mail if you need a print file)

    reflector should almost touch the lnb clamp

    try to avoid angled connectors (they produce more loss as half a metre cable bent in a nice wide open curve)

    greetz sigi dg9bfc

    and ... how does that poty work?? in principle it is a too long and a too short dipole as a cross ...both fed with the same current

    now what does a too long or too short dipole represent?? a radiator with a coil and a radiator with a cap inline

    and what does a cap/coil do?? they shift phase

    now ... if proper designed and tuned one element shift phase plus 45 degrees and the other shifts - 45 degrees .. voila 90 degrees difference (but with equally currents!!) and we have the circular polarisation

    and we do see that if the difference between the upper and lower resonances are around plus minus 2-3% (around 50 to 70 megs or 25 to 35 megs above/below working frequency)

    means the mechanical dimensions should NOT be changed and the feeding point must be at the absolute exact position to feed the elements with the right phases and current (and have the 50 ohms on that spot also with not reactance added) ... not easy but it can be solved with ... build it EXACT ... and finetune in very small steps with looking on the vnas smith diagramm (not to mention use a short cable and tune the cable out with osl calibration etc)

    a hint .. in several poty i made i had to slightly get the long edge near the feedingpoint a tiny bit closer to the reflector .. about half of a tenth mm only or so

    greetz sigi dg9bfc

    ps yes if proper tuned the circular polarity is good! and a single resonance spot does NOT mean both elements are tuned to the same single resonance .. BOTH TOGETHER form a single resonance with circular polarisation (see explanation how the poty works at the beginning of this text)

    if that dip is at the working frequency AND if that is at the top of the rollercoasterloop then it is perfectly tuned

    install it ...

    with such a high return loss you will see the return loss will go down a bit from your 50 or 55 peak cause you see the reflections from the dish back into the feed and any slight bending will detune that very deep notch ... a bit of distance change and the reflections come back in a different phase related to the tx energy and you see that deep notch again (will vary a few db depending on distance) ... if you have made your reflector from a not too thick copperplate then you should reinforce it a bit (i glued a HPL sheet at the back for a few feeds i made for cf dish)

    you can add a rim to the reflector (say a patch feed driven tubular waveguide) ... that can WIDEN the angle for f/d 0.25 to 0.3

    and ... as deeper the dish as more you have to look that the feed is at the phase centre ...for a patch with rim that means to place it a bit more away from the dish

    i have the same problem with picture freeze after a second but audio still works

    any hints what it may be?

    beaon decode works fine but i see that on several ham signals its difficult to find a lock

    and even if locked not always a picture is shown