ADALM-PLUTO (new DATV SDR)

[KenW6HHC]

I had a chance to compare 1.2 GHz transmissions between PLUTO SDR modulator and DATV-Express modulator using the experimental PLUTO-Express v1.25p1 from G4GUO.







The two signals both look nicely formed and equal on the spectrum analyzer. But the modulation constellation for the PLUTO looks tighter and the MER also is slightly better than for DATV-Express board (32 dB vs 27 dB) on the MiniTiouner analyzer. Not sure if I have done something wrong with DATV-Express board hook-up since I normally show MER=30 dB? Maybe the slightly wider RF bandwidth of 3 MHz at SR=2.2 MSymb/s produced a change?

I also discovered that the unused PLUTO Rx antenna makes a perfect antenna for the MiniTiouner when sending the signals across the table in my software lab.

73…de Ken W6HHC

[G4EWJ]

Further up this thread I showed the reception of 5665MHz by connecting a mixer to the MiniTiouner. It's important to note that if you do connect a mixer directly to the MiniTiouner, all power jumpers should be removed from the MiniTiouner so that there is no voltage on the F sockets, or you will blow up the mixer.

Brian

[KenW6HHC]

I just did another search for the out-of-stock PLUTO-ADALM SDR Tx/Rx units.

The distributor Mouser-USA reports Factory Lead-Time: 14 Weeks
This is consistent with what Mouser reported last week.

73...de Ken W6HHC

[G4EWJ]

Talking with Charles this afternoon, there is a problem with DVB-S below 521k symbols in version 1.25p1 where it gets rather wide, so DVB-S2 only is advised for the moment.

Brian

Pluto_DVB-S_SR333a.jpg (270.53 KiB) Viewed 9606 times

[KenW6HHC]

Charles G4GUO has just made available early-experimental alpha-release v1.25p4 software that corrects the RB-DATV wide-spectrum-“haystack” bug with DVB-S protocol reported by Brian G4EWJ. G4GUO explains the problem was caused by “math overflow” into one of the PLUTO buffers. The v1.25p4 software has just been posted to the DOWNLOADS page of the http://www.DATV-Express.com website.


PLUTO-Express v1.25p4 software running SR=333KS/s RB-DATV with DVB-S and H.264

73...de Ken W6HHC

[g0mjw]

Just testing with 32APSK at 333ks again with Charles's latest software. Very good quality video at 1.2 Ms/s. The only reason it's not HD is because I am using the free version of Vmix which is limited to SD.

Pluto-MinitiouneV2 32 APSK 333Ks.jpg (276 KiB) Viewed 9237 times

Hoping to try this on 70MHz when I can find someone who can receive it.

Mike

[KenW6HHC]

I checked the electronic distributor Mouser this morning to follow progress on PLUTO availability from Analog Devices.
The Mouser website shows December deliveries are expected.


PLUTO availability currently expected by Mouser website

73...de Ken W6HHC

[M5TXJ]

That estimated shipping date has been constantly changing since I ordered mine in August...

73 Dave

[F6DZP]

Hello,

the Serit NIM FTS4334 is very sensitive to any noise, jitter, distorsion.. in the signal. ( more than a Sharp or Eardatek)
I have worked the last/next version of Minitioune v0.7c to allow a better sync to low SR and also direct receiving of 70cm or 146 MHz signal.

DatvExpress gives a very good result down to 146 Mhz and low SR (70 kS/s) concerning only the modulation:
- the only big problem with the use of DATVexpress is the very bad TS that is produced ( bad synchro, bad PCR, bad audio PTS, bad video PTS..),
but the analog signal is fantastic!

So, I only want to compare the DATV express analog signal and the PLUTO analog signal using the Serit NIM:

Using the DATVexpress, at 146MHz, or 437 MHz or 1255MHz , all SR tested between 70 kS/s and 4000 kS/s, MER is always betwwen 33 and 36 dB and look at the constellations, they show a signal free of noise or artefact. Superbe!

DatvExpress_437MHz_SR075_8PSK.jpg (411.88 KiB) Viewed 9028 times

Using the PLUTO:

PLUTO_437MHz_SR500_8PSK.jpg (433.81 KiB) Viewed 9028 times

I can get a better synchro lock changing the Nyquist filter reference inside the demodulator, but the constellatiion/MER stay low quality:

PLUTO_437MHz_SR500_8PSK_Nyqyst_Ref_twist.jpg (411.27 KiB) Viewed 9028 times

So I think that there is something to improve in the PLUTO signal. ( each "cloud" is made of 4 little "clouds" )

Concerning Minitioune V0.7c (coming soon), result are better now than using a Sharp and direct reception of 437MHz or 146 MHz ( with preamp) now
has not less sensitivity than the use of a converter.

Jean-Pierre F6DZP

[G4GUO]

Hello Jean-Pierre,

Evariste F5OEO has told me of a problem he has found this morning where buffers are
being released before they are being transmitted.

I have also noticed myself that the Pluto software can do strange things when a parameter is changed.
As you know I am working on a GPU based decoder and I have seen this while I have been doing testing,
I have been using the Pluto as a test source.

Another possibility is that if it only occurs at symbol rates below 520K it maybe due to the fact that the Pluto
uses an external interpolator in the FPGA at low symbol rates and this has some gain which maybe causing
mathematical overflows. There was mention of the overflow earlier in this thread.

- Charles