Interesting comments, Andy.
My goal is also to be able to monitor all the digital portions of the band and
to be able to spot all call signs in any mode across the band. CW Skimmer is a
good model for that. In addition, it would nice to be able to select a few
segments of the band (~5 KHz span in each segment) and to be able to select a
few specific signals in each segment for continuous decoding in various modes.
As far as I know MixW is the only package that can decode multiple modes
simultaneously. PSDR and SDR-Radio allow the selection of multiple segments (2
for PSDR, 3 for SDR-Radio) but the integration with digital mode decoding is
not built-in with the SDR software.
The hardware capability to do much of this is available in many of the
computers in the consumer market. A few benchmarks that I have are:
MultiPSK in 4.3KHz wide panoramic mode with I/Q direct interface:
Dual core CPU, E2180, 2.0 GHz, 2.5 GB memory - 25% CPU usage
Quad core CPU, Q8200, 2.33GHz, 4.0 GB memory - 12% CPU usage
On the Q8200:
SDR-Radio uses about 8% average.
DM780 uses about 8% maximum.
The total CPU usage on the E2180 was around 35% - 40% with these applications
running:
MultiPSK in panoramic mode & the I/Q direct interface
HRD/DM780/Logbook
UI-View APRS
Weather Display
I replaced a 2.4 GHz single CPU/motherboard with the E2180 dual CPU/motherboard
last year and was very pleasantly surprised at the increased
capability/decreased CPU usage. About 1GB per CPU core seems to be sufficient
for ham radio usage.
Ed
WB6YTE
--- In digitalradio@yahoogroups.com, Andy obrien <k3uka...@...> wrote:
>
> One of the things that I wanted to accomplish with an SDR receiver,
> is the ability to keep an eye on the whole 14065 to 14115 frequency
> range. If I was down on 14074 monitoring ALE 400 traffic, I would
> miss Olivia signals that popped up in the 14109 area. I would also
> miss Hell signals at 14068. Now the SDR affords the opportunity to
> keep an eye all all at once. My venture in to SDR from a digital mode
> perspective has led to a discovery that, other than Multipsk, the
> current state of the art does not support direct monitoring of wider
> I/Q data. I'm also challenged in that my PC cannot cope with the
> Multipsk CPU demand when I try direct monitoring. So, at the moment I
> am visually monitoring signals with the SDR and using traditional
> software methods to decode the 3-4 kHz of audio that is fed from the
> SDR to applications like DM780 or Fldigi.
>
> At this screen shot http://www.obriensweb.com/sdrdm780.jpg
>
> you will see how it appears. I am simply using DM780 and SDR-Radio
> software together. When I need to transmit, I just use my TS2000
> after dialing in the signal discovered by the SDR receiver. Simon
> HB9DRV will likely "integrate" these two applications later in 2010.
>
> I did catch a Russian on RTTY this morning that I would have otherwise
> missed while I was slumming it in PSK31-land.. Multisk does RS-ID
> over this entire 14065-14115 portion, and DM780 is likely going to
> include this ability in the future. If people use RS-ID often enough,
> it will be really "cool" to monitor 14065-14115 and get RS ID alerts.
>
> So, just over a week playing around with the SDR receiver... I see the
> potential... digital mode applications are not quite "there" yet.
> When they are "there" (as in Multipsk) my PC isn't. This $41.00 Ebay
> PC may eventually get retired for a slightly improved one with better
> CPU. OK, back to keeping an eye on 14065-14115. A-ha, an SV3 calling
> CQ RTTY, 14082.
>
> Andy K3UK
>
