PC or not to PC   September 9th, 2013

Screen Shot 2013-09-09 at 21.50.13

I have had a few emails about SDR and seen some recent postings, all of which centre around whether PC controlled SDR processing should be done inside the PC, (as it always has been) or shifted into the radio itself. The only reason for doing the latter is if the data flow from PC to radio cannot be made fast enough or there is not sufficient capacity to handle the large flow of data. Of course radios like the Elecraft KX3, although SDR, are self contained whilst retaining the option to shift the processing into a PC because of an
I/Q output. Best of both worlds really.

Whilst, there is nothing fundamentally wrong in shifting the processing into the radio, the undisputed fact is that there are some significant problems. I have already mentioned that updating the CPU in the radio is problematical at best, and probably impossible in practice. Only the likes of Apple and Microsoft have the ability to keep pace with CPU developments. With the CPU in the radio it could mean purchasing a new radio every few years to keep up with technology. And the cost of developing the operational software is very significant and time consuming. Something that a small manufacturer would not want to take on unless there were very well established rewards and they had the resources and finance. And so the big question is, can this move really be a wise one? Its ability to work is not the question, it is rather the cost of keeping up to date with CPU development. So let’s reconsider the established and proven option of letting the PC do the work.

If there is a question mark over the data flow ability, one has to ask why the music industry can handle so much data fast enough, using USB2 and Ethernet. Here, the data flow is enormous and speed is paramount. Yet there are very few examples of CPU being moved to the hardware. And this data flow is being handled satisfactorily on very modest computers. I am not talking about iTunes and the like, I am referring to professional music production and hardware modeling.

So let’s come back to what I have at the moment. An SDR system that uses the PC for all the hard work. I can easily operate at 30WPM CW and use noise reduction etc via Ethernet. I can do all the data handling I need and open multiple receivers. In fact there is nothing much I can’t do! My current laptop PC cost me less than £400. In three year’s time I could probably sell it for £100 and it would cost perhaps another £300 to £400 for me to upgrade to a new CPU. Perhaps the question I should be asking myself is, how much would it cost me to upgrade to a new radio in a couple of years or so? That for most if us will be the deciding factor. Peter G3OJV.

This entry was posted on Monday, September 9th, 2013 at 8:52 pm and is filed under News. You can follow any responses to this entry through the RSS 2.0 feed.You can skip to the end and leave a response. Pinging is currently not allowed.

3 Responses

September 10th, 2013 at 8:59 am
Peter M0HBL Says:

I fully agree, Peter. Computers are mass market items which will remain low cost items (I hesitate to say, throw away items!). Radios of the sort we amateurs use will always be for a relatively small market. Keeping their cost down by transferring processing to the PC is arguably the best way forward.
Many young people nowadays are also well used to using computers and will usually have the latest type too!
Any more news on the apache lab SDRs?

September 10th, 2013 at 1:58 pm
Julian, G4ILO Says:

My objection to PC based SDR is that it will always depend on the availability of software, drivers etc. to run on the latest OS. My self contained K3 will continue to work in 10, 20 years time regardless of the PC I am then using

September 11th, 2013 at 11:52 am
Peter M0HBL Says:

Hello Julian, I hope you are feeling better than you said a few weeks ago and your health is improved. I understand what you mean but I think over time, we shall have more than just radios controlled by software and drivers, software etc will be provided routinely in the same way as in the past we required control knobs and plugs.
Having spent a lifetime in the physics community, it is noticeable how computers and computing, simulation and software are displacing much of the experimental training we (and I include myself here) did in the past. The world is rapidly becoming a digital one…

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