I agree with the statements above but would like to recommend to add some thoughts:
if your filter has significant insertion loss and/or limited power capabilities it is better to place it before the final PA.
Assume you are operating a 200W PA at 50W to keep it very linear for DATV and your filter has an insertion loss of 1dB
then you probably do not want those additional losses attenuating your precious power ...
Kind regards
Matthias
Hallo Hans,
ja, probiere mal mit der TX-offset QRG noch eine Feineinstellung zu machen ...
Gruss
Matthias
Hallo Hans,
wenn Du beim erstmaligen Eintragen der Konverterfrequenz eine seltsame Frequenz wie bei Dir 20547240.850 MHz angezeigt bekommst, dann einfach durch Eingabe der gewünschten Frequenz z.B. 10489.550 MHz überschreiben. Dann sollte alles gut sein.
Gruss
Matthias
Hi Robert,
yes, that is a bit too deep.
However my 1.8m dish has an f/D of 0.29 and really works well in reception.
Please also note, that the precision of the extension needs to be very precise on 10 GHz. it is not only the mesh size which need to be about 3mm max but especially the precision of the curvature.
I had used before a mesh dish with 1.9m diameter and f/D of 0.4 and when changing to the solid dish especially the reception improved a lot.
Kind regards
Matthias
Hello,
as DH1DA has mentioned you will reduce the f/D of the dish when enlarging the diameter while keeping the focal length the same.
This will be very beneficial especially on the receive side because the round waveguide has an opeing angle of about 130 degrees.
In receive mode you actually want to optimize G/T and not G. The deeper dish will pickup much less ground noise.
I am using a 1.8m PF dish with a f/D of 0.29 and even though I am underilluminating the dish I am very happy with the results.
NB transponder noise floor is about 8dB and WB beacon MER is about 9.8dB,
The POTY is certainly much better for dishes with a low f/D (my f/D=0.29 is clearly on the low end of the recommended range).
Kind regards
Matthias
Hallo Hans,
bei einer Stromaufnahme von nur 1A oder weniger brauchst Du bei 15m Kabellänge nicht wirklich bedenken haben. Nimm ein Kabel mir mindestens 2mm2 Kabelquerschnitt und gut ist es. Du kannst ja vor dem Transverter noch einen keramischen 10nF Kondensator und einen 1000uF Elko dranlöten. Dann kann eigentlich nichts mehr passieren.
Viele Grüße
Matthias
Hi Kurt,
this is really cool especially that you can use it together with the Minitouner.
Are you planning to support also the Airspy (R2), which is also supporting 10 MS/s ?
That would be really great as I am using Airspys here ...
Kind regards
Matthias
Hallo Martin,
Super wenn alles geklappt hat.
Da hast Du aber auch echt Pech gehabt ... so eine defekte F-Buchse ist sicherlich sehr selten ...
Viel Spass mit dem Konverter
Viele Grüße
Matthias
http://www.dd1us.de
Hallo Achim,
vielen Dank, genau und bei meinem tiefen Spiegel verliere ich schon 6dB wenn ich nur ca. 2cm aus dem Fokus bin.
Beim Optimieren auf das letzte dB war ich also schnell im Bereich von 5mm. Passt gut ...
Viele Grüße
Matthias
Hallo Kurt,
insbesondere beeinflusst das f/D des Spiegels, wie genau die Brennweite getroffen werden muss,
Bei flachen Spiegeln mit einem grossen f/D (wie die meisten sat-offset-Spiegel) ist es unkritischer,
bei tiefen Spiegeln mit kleinem f/D (wie meinem prime-focus-dish mit f/D=0.29) ist es schon kriischer.
Viele Grüße
Matthias
Hi Ribert,
you are very welcome.
Actually you can simply use the cosinus function.
Theoretically the loss at 90 degree is infinite but in the real world it is somewhere around 20dB (because the TX and RX antennas are most likely not ideally linear polarized and you might have reflections etc.).
Kind regards
Matthias
Hi Robert,
left not really as the transponder rolls off quickly.
Right maybe depending on the sensitivity of your system.
Sorry, bit I have not checked myself today the WB tpx for radar interference.
Kind regards
Matthias
Hi Robert,
of course the radar signal is not stronger than the WB beacon, which you are showing on your screenshot.
Kind regards
Matthias
Hi Robert,
interesting setup, but why did you take the route to circular polarization ?
If you use a normal linear polarized LNB and tilt it 45 degrees then you receive also both transponders.
Of course you will also loose 3dB on each transponder going that path.
Kind regards
Matthias
Hi Renaud,
the somewhat cyclic white lines are most likely from an unknown radar source. Today it is especially bad but it has been present for quite some time.
The pacman picture in the waterfall, which is transmitted cyclically, is to remind people to honor the guard band to the PSK beacon. 
Kind regards
Matthias
Please note that the tube acts as a high pass filter and suppresses the 2.4 Ghz signal.
The longer the tube, the higher the suppression.
I recommend to make it not too short but for sure not as long as shown in the pic from DD4YR above, I think 6 cm is enough.
Also don't use regular silicone (smells like vinegar) to glue the copper to the LNB ... that will react with the copper
and will be a mess ...
Kind regards
Matthias
Hi 4Z4LS,
that will be nice, many thanks in advance and good luck with your interesting project.
Kind regards
Matthias
Hi 4Z4LS,
thank you for sharing your ideas.
I am not sure I understand how you can operate with that unit full-duplex.
In addition how do you plan to deal with the suppression of your local oscillator and your image frequency of the 2.4 GHz upconverter.
You will need a very high Q filter to get to an acceptable level (min 60dB suppression !?).
In receive mode I propose to switch off the driver stage and the PA as you will otherwise generate additional spurious emissions due to your frequency generation scheme.Kind regards
Matthias
Hi Thomas,
why do you think that this should not be transmitted on the NB transponder ?
I think Roland was perfectly right: the used a bandwidth of less than 2.7kHz and the transmission was in the mixed mode part of the NB transponder. From my perspective all fine.
Kind regards
Matthias
