Perseus SDR and DRM

[Alan Johnson]

I just realized that I have two sound cards in my computer - an onboard Realtek chip (currently disabled in BIOS) and a PCI-e ASUS. I wonder if I could use them instead of Virtual Audio Cable and get better results with Perseus and Dream? Can someone tell me how to configure them? Do I set up one as recording device and the other for playback in the Audio tab of Sounds and Audio Devices in Control Panel? I'm running XP Pro SP2.

Thanks in advance,
Alan Johnson
N4LUS

[dadalbinder]

Hallo Alan,

just install/enable your Onboard-Soundcard and try to work with this situation.

If You call RECORD or PLAY-Mixer, You are able to choose the soundcard, You want to engage for a special purpose.

I try to append a screen from Winrad 1.31, where You could see, how it feels to have two soundcards. Sometimes it is a little complex, because all soundcard related programms try to optimize themself and change the fixing of the soundcard.

Take the weaker soundcard for output.

In some situation, the onboard-card is better than the additional card for decoding purpose.

Wolfgang Hartmann

PS: Till now, I do not use a PERSEUS

[mitajohn]

Hi all,

I found this rather interesting article by David Lipets of Tadiran Communications Ltd, concerning SDRs. Read all about it : http://www.rfdesignline.com/206902442 and also the Related Articles at the bottom of the third page.

[midre]

Hi all,

after some tests over a few days with the PERSEUS, which one I got from a friend , I resumed, PERSEUS is a nice small receiver with quite good results,
but not perfect at all, particularly on DRM....

- 800 Euro , this is a lot of money, if I have a look on performance and
handling(!)
- I didn´t get any stable signal ( on DRM !) with the receiversoft
( perseus 1.21d) , VAC and DREAM. There was a resync every
few minutes, and I don`t no why. I tried a lot of parameter in VAC,
different DREAM versions,but nothing helped...
- with the free software Winrad 1.41 everything is still working
( ..and in my mind , with a better performance!)
- and, btw. ,- high pc performance is needed for high Output Sample Rate..


Michael

[df9rb]

Hello Michael,

my Perseus is running very stable in DRM-Mode after a lot of try and error adjustments.
The most important settings are:
SR 62500 to 62500 and "cable format" in VAC and
Audio Latency 8 (minimum) in Perseus.

With these settings I have no resyncs in Dream for hours (under good condx)

The only little disadvantage of the Perseus is the not optimized AGC - but now the developer (Nico) started to redesign the AGC for Dream. He promised me a test version the next days.

Bernd, DF9RB

[mitajohn]

Hi all,

800 Euro , this is a lot of money, if I have a look on performance and
handling(!)

....and only up to 30 MHz (40 MHz wo preselector)...

[dadalbinder]

Hallo,

Winrad has a special management of Samplerates.

You are allowed to be free, to use a lot of different samplerates for input. I see for output only 8,0 kHz, 11 kHz and 24 kHz. Dream seems to prefer 48 kHz as other programs like SoDiRa.

I think, because of that feature, Dream has to change the samplerate while the signal is sent. This procedure could take some more processor time.

The AGC optimization for DRM is dependent from the velocity of AGC. The faster agc is working, the worser for decoding a signal. The whole signal in one period contains a lot of - let me say - subcarriers, which are combined by the digital process. It needs a certain time and withtin this time there should no remarkable changing of amplitudes of signals even there are only a few peakes to be seen.

Results of a lot of practice and changing agc-factors in experimental situations.

There is a program, able to change samplerates (RATEMONKEY), which could be usefull for the situation.

If Winrad will be changed in future to higher samplerates as 48 kHz for output the whole program would be dependent of more cpu power.

I hope, I gave right hints from my practical life in DRM.

Wolfang Hartmann, Nürnberg

[simone]

Originally Posted by df9rb

...
The only little disadvantage of the Perseus is the not optimized AGC - but now the developer (Nico) started to redesign the AGC for Dream. He promised me a test version the next days.

Bernd, DF9RB

Hi Bernd,
any news about the AGC yet?
Simone

[df9rb]

Hi Simone,

there is no new software available yet but I am very confindent that Nico will keep his promise as he always did in the past.
I will give more informations and test results as soon as the new software is available.

Bernd, DF9RB

[df9rb]

Hello all,

the new software for the Perseus (Version 2.1f) was available for some time.
Now I found the time to test the new AGC for DRM. The result is amazing.
With a synthesized DRM signal the SNR is now up to 51 dB!
Over the air test showed always a better SNR than my good old DRT1 and a few less audio drop-outs under critical conditions.

Bernd, DF9RB

[df9rb]

Hi,

Perseus and DRT1 sharing the same antenna. Signal with strong and fast fading. 1st Perseus, 2nd DRT1

Bernd, DF9RB

[Digger]

Originally Posted by df9rb

Over the air test showed always a better SNR than my good old DRT1... Bernd

Hi Bernd,
How about give VoR from Bolshakovo a try for SNR? 9.73 MHz topped 40.96 here on my FRG-7700 one day and this morning (so far) 39.98 dB.

[mitajohn]

Hi all,

@Bernd, excellent... give it a try and specify HW & SW setup, antennas, preselector if any, filters....

[df9rb]

Hello Terje, John,

Terje, I think during you typed your message I was listening to VoR.
But today was deep fading and a PLC-modem was active (I couldn t find out until now from which neighbor it comes from....). So the maximum SNR today was "only" 38 dB.
John I used a CD with an DRM-Signal, fed to a mixer (NE602) following the Perseus tuned to 477 kHz. This signal was for sure no optimal but i did not have something better.
The On-Air test was with my EWE antenna and a simple T-Plug (nothing matched!) deviding the signal to the Perseus and DRT1.

Bernd, DF9RB

[mitajohn]

Hi all,

@Bernd,

...I used a CD with an DRM-Signal, fed to a mixer (NE602)...

I see... the old fashioned way...