Softrock Ensemble RX performance.

[Leif Asbrink]

Hello All,

Today I uploaded a video on youtube:
https://www.youtube.com/watch?v=7El6Iq8WgJE

In this video I compare 5 radio receivers:
FT1000
IC706MKIIG
Colibri
Afedri NET
Softrock Ensemble.

To get it all you will have to spend one hour and 25 minutes...
The video will convey much more information than simple performance
tables.

The general conclusion is that the Softrock is much better than
all the others at close range while the FT1000 is much better than
the others at wide range.

Conventional BC receivers from about 1950 would have IF=455 kHz and
a two-gang variable capacitor to provide RF selectivity to bring
the mirror image 910 kHz away down to an acceptable level. Such a
simple preselector in front of a Softrock Ensemble would make it
the winner at all frequency separations. One LC resonator with
a multi-position switch to select the frequency band:
100 - 300 kHz
300 kHz to 1.5 MHz
1.5 to 4.5 MHz
4.5 to 14 MHz
13 to 35 MHz.

Five bands. Probably it would be possible to use four bands only.

The video shows the performance of my modified Softrock Ensemble,
but its superiority over conventional radios id bigger than the
about 10 dB that it is improved compared to the original Softrock
Ensemble.

73

Leif

[Conrad PA5Y]

Hello, I hope that someone sees this and can answer tonight.

I have set up my Afedri to use alias mode but there is a passband
reversal. How can I fix this? Let me give a clear example.

I set the centre frequency to 50.400
I look for PI7SIX beacon on 50.425 and it is on 50.375

I think that this is expected behaviour and I expect that this is a
single parameter change but I do not know where it is. Can anyone help?

Regards

Conrad PA5Y

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[Conrad PA5Y]

In wusers_hwaredriver.c

I changed

fg.passband_direction from 1 to -1

Then compile/make

No difference, I could really do with a fix for this before a contest
tomorrow, I need my Linrad bandscope!

Regards

Conrad PA5Y

[Leif Asbrink]

Hi Conrad,

It is too late for the proper cure, but maybe you could
get what you want by use of the converter option.

LO would be the Nyquist frequency and you might try the different
options and my feeling is that one of them would give you the
result you want. (Provided that the Afedri would not understand
that it should add a low pass filter when you ask for a frequency
in the first Nyquist region.)

73
leif

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[Conrad PA5Y]

Good morning Leif.

I have to say that I am fairly surprised that swapping the I & Q
channels is not easier, it was easy with HDSR just click :-) However I
would prefer to use Linrad so if you have time to implement something
that would be great. Maybe a AFEDRI specific setting? Invert spectrum
when in alias mode or something similar. Alias mode is identified when a
frequency is selected that is above the Nyqusit frequency? I am not a
programmer (at all) so I have no concept of how complicated this is but
it seems not too difficult?

Maybe Alex can do something in firmaware? I'll ask him also.

Regards

Conrad

[Leif Asbrink]

Hi Conrad,

It is already done for the SDR-14 which also can be
run in Alias mode. It is not complicated, but my agenda is full
right now.

73

Leif

[Conrad PA5Y]

OK Leif when you are ready, I much prefer to use Linrad rather than
HDSDR, the filters and NB are much better.

Regards

Conrad