Hi Stefan and Dirk

>Is it necessary to run such a power consuming software/hardware? At least for 
>LF i know the kit by JA8SCD which is not much power consuming

I agree this is overkill, but I have my Perseus almost dedicated to SWL on 
LF/MF and would like to take advantage of
its performance. For the grabbers will run SpecLab anyway, but for the digital 
modes I have to set different instances
Of the decoding software and feed each with its independent audio from a 
virtual receiver tuned to the proper frequency

Dirk, I'm running Perseus 4.01b. There are no more updates but I really don't 
need them. Perseus software exceeds my
needs and if there is something you want to try there are many other pieces of 
software which can use Perseus hardware
One of them is Studio1. It is not free but has all the bells and wistles one 
can dream about. For my needs, the value
of this software is to let you open many virtual receivers working all with 
just one SDR hardware

Every virtual receiver can be set with its own qrg/mode/filters/etc but all of 
them must fit into the available sampling
band of the SDR hardware. Each receiver will send the demodulated audio to a 
different audio card. So you need to run also
A Virtual Audio Cable software to create this audio links between virtual 
receivers and Opera/WSPR/SpecLab instances

You can download the software and a 500Mb wave file. So test yourself its 
features and open many virtual receivers
 http://www.sdrapplications.it/

Note that the Elad receivers come with a similar software which let you open 
some virtual receivers. But of course this
Software is just for Elad hardware. Same happens with the Flex 6000 and 7000 
series, I'm afraid

Just wonder if this is the way to go or if there is other simpler/cheaper 
approach

73 de Luis
EA5DOM