@Markro: decoding of >75% of all streams works good, only on a few signals i can't get a lock. When i encounter the next time such a "strange" signal i try to increase the loop gain.
Another (stupid) question: how can i detect if it is a DVB-S1 or a DVB-S2 signal?
Till now i only found DVB-S2 sigs.
Greetings DB8TF
.. and you can easily build one on your own:
http://www.vk3um.com/interdigital%20filter.html
vy73 DB8TF
I8LYL former I0LYL: "old" Octagon OTLSO (standard 27MHz) now running on 26MHz TCXO for use with standard DVB-S2 receiver.
LO 9388,9MHz
vy73 DB8TF
@MarKro:
I have a solid circle (but no carrier recovery working) in the IQ plot and sync confidence to 256 but when i show the modcodes following shows up:
Tony, first of all yesterday many Signals were not good decodable.
On your 3rd Picture you see that the SR value (number below waterfall) is way of 250ks...
Try loop damping at 0,002 and loop gain about 2-4.
What are those many lines you see in the waterfall in pic 3&4?
They normally don't appear.
Also set BBb gain a little bit lower, here it works best when the signals are bright blue and decoding gets worse if they turn to yellow
vy73 DB8TF
In some of the DATV Signals (in the AMSAT beacon too) you see a faint signal exactly in the middle of the Signal.
Decoding here works best when i click on this signal and so center the DATV signal using this "Pilot" tone.
First remove the enabled from the carrier recovery Checkbox, that makes tuning easier.
then center the signal EXACT in the middle of the waterfall, sometimes you see a faint line in the middle, this is the pilot tone (appears not on all signals!)
Then again select the bitrate in the upper Right corner > 250/333 usw.
if you now see a CIRCLE in the IQ plot THEN enable the carrier recovery and you should see the four points there.
Now the stream to VLC should work.
So nobody has used a MCXO till now..
Look at the first datasheet i posted.
±30ppB
see here: https://de.farnell.com/search?st=MCXO
About 50€ but unfortunately a suitable frequency (25/27) MHz is not in the list.
But the technical data looks very impressive.
VY73 DB8TF
OK Dave,
but those SiTime MEMS TCXOs are not the same as the MCXOs i mean
even if the name M-CXO could be understood as MEMS TCXO.
You can see on the datasheet that the stability is much better.
So i guess till now nobody has tried a mod with a "real" MCXO.
VY73 DB8TF
Dave could it be that the "Si Time 0.1ppm" are normal TCXOs?
https://www.mouser.de/datashee…7-datasheet_1-1371858.pdf
I see 0,1 / 0,25ppm on their datasheets.
The MCXOs are described with 0,02 / 0,03ppm stability.
Vy73 DB8TF
Hi Dave,
what is your impression with this MCXO stabilisation?
Does it work so good like it sounds according to the datasheets?
I can't find any posts from you about that here in this forum.
Vy73 DB8TF
Hello OMs,
has someone already tried a LNB mod with a MCXO like this one?
https://www.vectron.com/products/ocxo/mx-503.htm
Looks interesting, stable like a OCXO but current consumption likeTCXO.
vy73 DE DB8TF
After playing some days with this nice Software may i ask for some "improvements" if Markro finds the time?
It would be nice to be able to directly switch to the common SR rates instead of using the slider or typing in the values. I think a automatic setting would be complicated/hard to program.
So maybe add some buttons which set SR to 250/333/500/1M/2M with one click.
Every time the SW ist started i have to set the gain and frequency new, maybe this values could be stored.
To get the Information of the FEC you need confidence about 256 but only seldom you get that far, could it be possible to get a predicted FEC indication a little faster, maybe even with automatically setting the decoder to that FEC?
Actually i need to switch through all FEC Settings and have to look where VLC starts to play.
Besides of those small "improvements" this software works really nice 
BTW, i observed that it makes a big difference in stable decoding DATV streams if you use
a "wobbling" LNB or a stable one AND also a TCXO stabilized DVB-T stick instead of the "cheap" ones.
vy73 de DB8TF
Maybe you could listen to the audio i recorded a few weeks ago:
difference between Opticum AX Black Buster an GM201
Link> Excel spreadsheet for concentrating infos of LNBs for EH2 RX
yv73 de DB8TF
The "drift" is a completely different thing than the "wobbling".
I listened to your MP3 and the signal sounds not so clear to me.
For SSB reception ok but not "optimal".
The 4 GM201 i tested here had differend strengts of wobbling, 3 were not so good and on one the signal clarity was way better but not even close to a good not wobbling LNB.
The goobay was worser than the GM201 ones.
I also tested a HD Line Black Premium and this LNB was not even usable for SSB reception. But it is a PLL LNB with similar components like the OTSLOs.
The best performers were the Octagon OTSLOs and the Opticum AX Black Buster twin.
If you want to talk about this issue we can later carry out a QSO on the sat if you like.
vy73 de DB8TF
Maybe you have misunderstood me, i like to know if the unmodified LNBs do wobble, listen to the CW beacon and hear if the sound is clear or wimmering.
This has nothing to do with TCXOs or other HW stabilization methods.
For sure the wobbling is gone after a modification.
The Goobay and GM201 i have already tested here and now i like to know if you can agree to my observations that they don't give a clear signal.
vy73 de DB8TF
Hi Harry,
please check the wobbling of those LNBs before you modify them with TCXOs
Vy73 de DB8TF
For OMs like me who use the SW drift correction a LNB without wobbling is needed.
I tested some LNBs and found that the Octagon OTSLOs (25&27MHz Versions) and the Opticum AX Black Buster Twin performed best.
The Goobay 67269, GM201 and HD-Line BP2 are wobbling. At least the ones i have here.
vy73s DB8TF
