Minitioune v0.6d can use the new NIM SERIT FTS-4335

[F6DZP]

Hello,

The new versions of
Minitioune,
TestMyMiniTiouner,
CheckMinitiouneDriversandFilters,
NoisePowerMeasurement
are now available for download.

These new software can accept different NIMS : SHARP, Eardatek and the new SERIT FTS-4335 available (soon) at the BATC shop

This new NIM can receive from 144MHz to 2450 MHZ without any converter.

link for download:
http://www.vivadatv.org/viewtopic.php?f=60&t=416

minitiounev06d_expert_lockSR250_H264_DVBS2_.jpg (304.87 KiB) Viewed 7691 times

Enjoy!

Jean-Pierre F6DZP

[F6DZP]

I forgot to say that with this new NIM we can also receive DVB-S2 16APSK and 32 APSK

test made with my DATVexpress as modulator:

minitiounev06d_standard_lockSR2000_H264_DVBS2_16APSK_.jpg (226.82 KiB) Viewed 7629 times

minitiounev06d_standard_lockSR1000_H264_DVBS2_32APSK_.jpg (228.42 KiB) Viewed 7629 times

Jean-Pierre F6DZP

[G4GUO]

The reason the MER is so low is that I have the preamble in DVB-S2 set to the wrong value
in the currently released version of the software.

The reason I have done that is because when I have it set to the correct value my Satlink
receiver won't decode 32 APSK. I have no idea why.

I look forward to upgrading my system and trying out your new software when the BATC
NIM bodge boards are available.

- Charles

[G8GKQ]

I had the opportunity to investigate the behaviour of the RF Power Indication on MiniTioune 0.6d with a Serit FTS-4335 Tuner earlier this week.

At 1255 MHz, with a constant -60dBm DVB-S H264 input (sourced from a DATV Express measured at 0 dBm with 2 x 30 dB attenuators in line) the reading was directly dependent on the SR being transmitted and decoded:

Code: Select all

SR   Reading

4Ms    -70
2Ms    -64
1Ms    -58
500Ks  -52
333Ks  -50
250Ks  -46
125Ks  -40

I also measured the reading at different frequencies at 1Ms, which I believe gives some measure of the relative tuner gain at these frequencies:

Code: Select all

Freq    Reading

146.5 MHz -58
437 MHz   -56
1255 MHz  -58
2400 MHz  -62

So it appears that the tuner has most gain at 437 MHz, with 2 dB less at 146 and 1255, and 4 dB less at 2400. It is was not possible to read this across to sensitivity, as I was not able to measure the tuner noise floor; this would be irrelevant assuming adequate pre-amplification is used.

Lastly, I attempted to characterise the linearity of the power indication at 1255 MHz, 1 Ms.

Code: Select all

Input Power  Reading

-70 dBm     -70
-60 dBm     -58
-50 dBm     -53
-40 dBm     -49
-30 dBm     -45
-20 dBm     -39
-10 dBm     -32
0 dBm       -20

I was not able to reliably generate signals below -70 dBm, but it does appear that the scaling of the output indication might be different for the 2 AGC indications ranges shown in MiniTioune.

In conclusion, it seems that the indicated power level is dependent on SR, with a linear 6 dB/octave correlation, but at constant frequency and SR, the power level indication gradient varies from 4 dB/10 db input change to 12 dB/10 db input change. Please note that all readings are +/- 2 dB.

Given this information, the MiniTioune software can be used to give an indication of the absolute level of decoded DATV signals. Another use for this excellent software!

Dave, G8GKQ

[g0mjw]

That's interesting. Its good to see its gain is fairly stable with frequency and the power detector works as expected for power per Hz. I think this is what you want for digital but simple to change in software if absolute power is needed instead. Its disappointing but not surprising that the linearity is not good. However, it is at least monotonic so higher is better when tweaking the antenna.

I'm looking to replace the F-connector on mine so it will still fit in a Hammond 1455 series 110mm wide case. It should be easy enough to do. I am not a fan of F-connectors and once I have a proper connector in place I can do some real measurements. However, the F is 75 ohms and if your setup was 50 ohms this might explain the small variations across the band. Easy enough to correct of course.

Mike

[g0mjw]

Today I have been doing some tests - firstly I have the tuner in a box now, which shouldn't have too much of an impact on the results.

Testing with my DATV express via a coax and lots of attenuation. I will try and do some proper tests later on, but a quick observation is for a given signal strength the MER on 2m seems quite a bit worse than 70cm which is worse than 23cm. In practice its probably not a problem. Its certainly good to have a tuner that works from 2m to 13cm.

I would be interested in similar results. I am seeing MERs in the 15-20 dB range. Never higher - on the sharp tuner MER end stops. Now this might be because they are being calculated differently in the new software. Given this is a cabled link with good but not excessive signal strength - there should be some reason for this. I will check the PSUs with a scope just to verify boxing it hasn't resulted in some strange resonances or earth loops.

Meanwhile, back to preparing for Sunday's activity.

Mike

[G4GUO]

Mike, I have the preamble sequence set to the wrong amplitude on DVB-S2 that is why the MER is so low.
When I set the correct level the MER is the same as with DVB-S on the Express. The reason for it being at the wrong level is
that is the only level it works with my Satlink on APSK32 mode.

- Charles

[g0mjw]

Regrettably, this was also true for DVB-S so I think its a phase noise thing. The Sharp with a converter was a lot better

Mike

[G8GKQ]

Mike

I have seen the effect that you describe; it is phase noise on 146 and, to some extent, on 437. You can improve the MER to 26 or 27dB by making sure the tuner feed impedance is sightly capacitative.

More details here: http://batc.org.uk/forum/viewtopic.php?f=105&t=4860. After applying this modification, the tuner seemed to have exactly the same performance as the Sharp both for the acquisition of weak signals in noise, and for indicated MER at high S/N.

Dave, G8GKQ