Minitioune V0.5a is available

[F6DZP]

Hello,

I happy to announce that the new version is ready.
http://www.vivadatv.org/viewtopic.php?f=60&t=399

Main improvements over the v0.4c

• We can now receive DVB-S and DVB-S2 en QPSK et 8PSK
• We can decode video codecs : Mpeg2, H264 and H265
• More accurate values for MER and power
• Some little bugs fixed

• Useful for a PIPO,
o A click on vu-meter « MER/SN » changes standard/Expert mode
o A click on vu-meter « RF Pw » switches the AutoPID button
o A click on vu-meter « TimingLock » changes the DVB mode(DVB- S, S2, Auto)
o A click on vu-meter « CarrierLock » asks a new lock (= « 1search »)
o In standard mode, un click on thea video changes the display format ( = Echap)

• There are new FEC values for DVB S2

• We can preset the BBgain value and the lowSR/highSR mode

DVB-S2 8PSK SR156_.jpg (212.4 KiB) Viewed 9059 times

using only a SR of 156 kS/s !!!

Jean-Pierre F6DZP

[g8gtz]

As Jean Pierre says "More accurate values for MER and power" - it looks like what was 31 dB MER on previous versions is around 26 dB on version 5 - which is probably more realistic....

Noel - G8GTZ

[F6DZP]

less optimist....

It is very difficult to find the real value, when many analyzers say nothing above 25dB, when many analyzers don't work under 1MS/s, when analyzers can answer only for themselves, their own hardware that affect the received signal.

Since I had revisited Tutioune1600 for the Low SR version, I have not spend time to actualize the MER values, and keep the same table for Minitioune.

With this version, I have spent many tens of hours to show the most real value. changing the NIm, changing the SR, changing the mode...

We can better now also that the MER goes down when we change from SR2000 to SR250, the fineness of constellation shows itself that the MER goes down, yes I have 31dB at SR2000 and 26dB at SR250
We can see also when it is worth to work in low SR mode or not (the SR between 300 and 6500 can be used in both modes)

Jean-Pierre F6DZP

[g0mjw]

I recall doing something back in the early 90s based on the spread of the constellation and relating it to the Eb/No. I.e. mapping the soft decision values deviation from their mean. I had assumed that MER was based on something similar but maybe this is also a useful metric? It appears that data is available in the constellation diagram.

Mike

[F6DZP]

Yes I think that we could use the data from the constellation diagram, but there are some registers in the demod chip that change completely the dispersion of the constellations. And it is quasi impossible to know the "true" position
try to change the "post nyquist ref" value in Tutioune1600 or Tutioune3200 and you will see that you will obtain a better, more concentrate position of the constellation, but the SN or MER remains the same...

Yes I think that it is really a hard job to try to approach the most realistic value.
There are some tables given by ST microelectronics, but it is only for the way that they setup the chip, and for receiving low SR, I have changed the values used by STMicro, so changed also the way the constellations are shown.

For this last version, I have tested at different SR, using low SR mode or not, and I have compared with a DVB analyzer - when it could work - (not at very low SR) and I have compared also to the values in the tables given by STMicro using a switch to change the parameters between the StMicro values and the "f6dzp' values.

I think that, now, the values given are more realistic (but less optimist).

Jean-Pierre

[g8vpg]

I wonder if anyone knows of the lines to add to the configuration (ini) file to preset the DVB mode on start up. We are using Minitioune for the experimental 146.5MHz input to GB3ZZ and it would be useful to set this to auto, so that we can try both DVB-S and DVB-S2.
73 Shaun G8VPG.

[F6DZP]

No, there is not yet this option.
I will add it to the next version.

Jean-Pierre F6DZP

[cashy666]

Hi all,
does anyone know where I can get a NIM suitable for the Minitioune?

I have followed the links without luck.
Im not really technical so really could do with being pointed in the right direction.

thanks

Dave
G7MEG

[F6DZP]

You can find NIM (Sharp) at the BATC shop I suppose.
https://batc.org.uk/shop/hardware-and-kits
oups! out of stock?

direct from China:
https://www.aliexpress.com/item/NEW-BS2 ... 0.0.UsPWUs



Jean-Pierre F6DZP

[g8gtz]

Sorry Dave missed your post - as JP says we are out of stock of the Sharp NIM.

However, we do have 100 of the Serit NIMs which cover from 140MHz right through to 2650 MHz without the need for any upconverters!

This makes building a receiver for 146 or 437 much easier, although you will need a pre-amp followed by lots of filtering for each band, just like the Sharp did, and probably followed by a Satellite line amp from ebay as the Serit has less gain than the Sharp.

However, due to different pinouts, they also need a simple adaptor board to enable it to be plugged in to the Minituner standard hardware - Brian G4EWJ has designed one and they are currently being made in China.

20170115_171905.jpg (81.28 KiB) Viewed 8476 times

Brian is also ordering the components (no surface mount) to make up kits and once the boards arrive - end of next week? - these and the tuners will be on sale in the shop.

We'll post an update when they are ready.