PCI SDR Rig

Alex_KM5YT

At winradio.com (WR-G35DDCi 'EXCALIBUR Ultra) they have a PCI-interface shortwave
receiver.  I think this would be a very nice idea for a FLEX rig - a direct bus interface, even though it does require a tower config, and one has to be serious about the RFI issues.

John

I often look at the high price tag for various "professional receivers" and then wonder what I could purchase for that money. Our local emporium had a used receiver with a price tag of £7000. Now dont get me wrong, I appreciate all the technical stuff that goes into the box, but still, a receiver for 7k, when one could purchase a flex for half that price. Maybe its just me getting old and more grumpier by the second.

73
John

Alex_KM5YT

John - I searched - somewhere (?) - and had the idea the price of the Winrad PCI unit was near $1000 USD - but if that unit is ~ 7000 GBP, it's a bit off the deep end.  I am more imagining Flex putting something like a 3000 equivalent into a PCI board.

73,

Alex / KM5YT

John

Hi, well even at $1000 for a receiver is a high price. I was merely pointing out the price for receivers only compared to a transceiver. I think the flex transceivers have a good enough receiver section , unless you want something better at low frequency's. Why do you want to interface a XCALIBUR Ultra TO A FLEX ?

Alex_KM5YT

What I want is for FLEX to consider producing a PCI-board configuration of an SDR transceiver.  If I didn't express that clearly in the original post, my apologies.

John

Ok, all understood, early morning brain drain apologies. If you mean a plug in flex pci card with everything onboard, then it may not be possible for one reason and that being it would need to be wrapped in an aluminium box for use as a heatshield. The space limits inside a computer around the slots  would also not help either. How ever, if you meant a pci adapter on the back of current flex transceivers, then it may be possible.
What advantages would it give the user ?

Alex_KM5YT

I meant an integral unit as the winradio appears.  Advantages: control convenience; low-profile station (fewer boxes & cables; discrete).  Thermal can be an issue - Peltier effect cooling could be a
compact (if ~high-current) solution.  Streamlined PC-SDR communication: DMA could be used. 

Stan VA7NF

Interesting thoughts.  Only a few small shielded sections. 

Up to Antenna AD needs protection from internal PC noise

Everything up to DA for transmitter is digital - unshielded

DA out may/may not need shielding.  Only need enough power to drive external amplifier - Say QRP 5W on card and external PA option.

73

Stan

John

for what I call desktop computers, it would need to be shielded and with new devices coming out which can serve multiple purposes, it may be easier and more compact.

Peter K1PGV

Well, first of all, you'd want to make it PCI Express, not PCI. The easiest way I can think of to do this would be to have the radio card duplicate the bus-level (register) interface of a well know NIC. In that case, everything on the host side could remain unchanged. That's a big change for the Flex hardware/firmware all around. And I'm not sure what it would gain, frankly. Peter K1PGV

DH2ID

I have tried a WinRadio PCI card once and am happy with my external WinRadio, which I use as a test receiver nowadays. The WinRadio system as a SDR is quite "old" but I am happy with it's recording abilities.
Reason I had problems with a PCI card: lots of interference, birdies, you name it. Couldn't get the PC quiet enough.
73,
Alex

Alex_KM5YT

PCIe subsumed.  After firewire, then ethernet, PCI is no great leap of communications abstraction; I see no conceptual change - and see DMA data transfer as a big plus.  My only thought in this topic was for discussion.  After that it's up to Flex marketing and engineering.

Peter K1PGV

Well, it IS an interesting point for discussion.

I see no conceptual change - and see DMA data transfer as a big plus

The problem is... where do you DMA the data to?  What software in the host system is going to (a) allocate the memory for and setup the radio device registers to perform the transfer, and (b) receive the data and get it over to SmartSDR?

Right now, SSDR talks to the network to control the radio and get audio.  You either have to write a custom device driver for the radio and change the bottom edge interface for SSDR, or find some way to mimic an existing interface so that SSDR still things it's getting data from the network.

You'd wind-up with *much* lower latency (from radio to host... but is that even important?), but probably not much less of a CPU load.

You'd lose the market of people who want to remote to the radio without a computer at the remote location.

If you were willing to re-write SSDR, you *could* push a *ton* more data between the radio and SSDR... get significantly higher resolution in the panadapter.

It's an interesting concept, but I personally don't see any significant advantages.

John

do we want to move into "pulling callsigns out of the ether" like wsjt,with a higher resolution panadapter with say a deep search facility. I can only see an improvement on the uWave bands as HF is too crowded but narrow filters could remove a lot of the crud.

Alex_KM5YT

I did not propose the idea with the thought of replacing the network interface - just as a configuration option which Flex would decide.  I see a DMA interface as simpler and tidier than any network logic I can recall (I don't actively play with machine-level stuff anymore) - but the advent of optical networking on the Flexs will outrun that, too, soon enough.