New computer for SDR's - some questions

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Paul_Logan
Posts: 109
Joined: 24 Sep 2014 12:58
Location: County Fermanagh, Ireland

New computer for SDR's - some questions

Post by Paul_Logan » 11 Mar 2015 14:22

Hi all,

I am in bad need of a new computer to run SDR's.

I have struggled along with a laptop (Intel Core Duo p8700 @ 2.53 ghz, 4 gb RAM) but I really need something better. This machine struggles to run my ELAD FDM-S2 and even Perseus with lots of skipping on file playback that I have never been able to get to the bottom of even after lots of effort.

So here is my question. What should I be looking for in a new system.

Laptop or desktop?
Operating system?
Size of processor?
Amount of RAM?
Hard drive - SSD?
USB - 2 or 3?
soundcard - what ones work with rds spy?

There are other considerations such as power supply if buying a desktop (some are noisy buggers) same goes for display (some of those are noisy buggers too)

It's a potential minefield! So what I am looking for are a few pointers or suggestions as to what i should be looking for, or even suggestions of existing systems in use which are working well.

Any help or suggestions would be a real help.

Getting the ELAD working and being able to avail of it's full recording abilities would be a real step forward - even if it means me deciphering files in the dead of winter (who said you cant have summer all year round!)

look forward to any replies....
Paul Logan
Lisnaskea, Fermanagh, N. Ireland IO64GG

FMDX: Elad FDM-S2 with 5 el Yagi by K6STI, Andy Bolin Phaser.
MW / SW: Perseus / Elad FDM-S2 with Inverted L wire / Wellbrook Loop.

sleeper77
Posts: 458
Joined: 28 Feb 2015 14:48
Location: Southampton, England
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Re: New computer for SDR's - some questions

Post by sleeper77 » 11 Mar 2015 22:36

Here is something to think about...

- I recommend a desktop over a laptop. The power supplies of laptops cause a lot of RFI for LF, HF & Low VHF.
- If you want to keep your laptop, have you tried defragmenting the hard drive? How about trying an SSD which is much faster than a hard drive?
- Do you have a lot of processes running in the background? This can consume a lot of CPU & RAM power. Get rid of as much as you can
- Make sure there are no program conflicts causing skipping on the SDRs
- I use Windows 7 for my SDRs & they run fine
- I use USB2 & it is still fine. No hiccups as of yet
- I mainly use an Intel I5 2500k desktop with a dedicated graphics card but it does the job fine. Overpowered for the SDRs, the most I have seen is 25% CPU usage with other programs running in the background.

Overall, you do not need to spend big to get good SDR performance on a PC. Try finding out what is causing skipping on your laptop first.

Damien Read
Posts: 76
Joined: 17 Nov 2014 20:20

Re: New computer for SDR's - some questions

Post by Damien Read » 12 Mar 2015 22:20

I would totally agree, I recently installed a SSD hard drive in my sons laptop which runs windows 8.1, it takes 5 seconds to boot, it used to take about 50 seconds.

Even a budget dual core, like a £100 dell used desktop, with a E8400 cpu will easily run a Elad.
Honestly, you don't need to spend a packet.

It is worth mentioning that by the end of the year, Windows 10 will be released, best of all it will be free. I am running a beta version now, and haven't really had many issues so far.

Damien
Stourport on Severn WORCESTERSHIRE

satnipper
Posts: 926
Joined: 03 Oct 2014 12:58
Location: Western Europe

Re: New computer for SDR's - some questions

Post by satnipper » 13 Mar 2015 09:22

"Even a budget dual core, like a £100 dell used desktop, with a E8400 cpu will easily run a Elad" - Try recording or listening to a 6 MB bandwidth SDR file, web browsing and listening to a mp3 at the same time...

As always with computers you buy the best you can afford knowing that within a couple of years you'll be behind the performance curve again. The 10 MB Airspy is here now, I'm sure the 20 MB unit will be here in 18 months. Recording the whole of Band II will require more than a clapped out old Dell.

Windows 7 is all you will need for the next five years at least.

Stuart

ps

I hear the new Raspberry Pi 2 is good.

daveB
Posts: 1217
Joined: 07 Oct 2014 16:49

Re: New computer for SDR's - some questions

Post by daveB » 13 Mar 2015 09:42

I agonised over upgrading too and had pretty much the same concerns as yourself.

First of all - the benchmark speed figure for you laptop CPU is 1664 - which is worse than my laptop CPU at 1813 and it wouldn't run an RTL stick at 2.8 MHz bandwidth. So I looked around at the various offerings of computers and checked the CPU benchmarks - looking for something with 4 x the benchmark of my laptop or better.

I ended up with a PackardBell iMedia S2885 mini tower with an i5-4460 (CPU bench mark 6692), 8Gb RAM, 1TB hard disk for £429.00 It included built in wi-fi and wireless mouse/keyboard. Six USB ports - 2 x 3.0 ajd 4 x 2.0. It's very quiet and isn't generating any electrical interference as far as I've been able to determine but I have had ferrite chokes clipped to all the leads going in/out of my computer ssytem for ages. It has a full metal caae. Running SDRPlay at 8MHZ bandwidth the CPU usage is 12-20% according to HDSDR. I normally run it at 5MHz bandwidth as I find it easier to see the weak signals close by strong signals. DABPlayer 2 on an RTL-dongle is happily running at the same time. The soundcard complies with the HD audio spec and I'm currently using two instance of RDSSpy directly decoding RDS from the unfiltered audio at 192kHz sampling rate - one from HDSDR and one from the Yamaha TX-930.

I have just checked what happens when I try recording the full 8MHz bandwidth - I couldn't see any additional total load on the CPU which stayed at around 25%. Playback was without stuttering - but recording sure eats up the megabytes!. Still PC came with the hard drive partitioned into two with drive D: at 500Gb being labelled "Data" - so the perfect place to send the raw RF files to and keep track of!

To give you an idea of the difference in CPU speeds. The i5-4460 has a benchmark of 6629, an i3-4150 is only 4926 - the higher the benchmark the more the CPU will handle. There are various 'flavours' of the s2885 and PCWorld is currently offering the one with the i3-4150 for £399 which might not be powerful enough. They are currently offering re-furbished models of the i5-4460 version for £299 on-line. It doesn't specifically say that it has wireless keybd/mouse.

Hope that is of some help

Rgds
David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

daveB
Posts: 1217
Joined: 07 Oct 2014 16:49

Re: New computer for SDR's - some questions

Post by daveB » 13 Mar 2015 10:28

"Recording the whole of Band II will require more than a clapped out old Dell".
It's the playback that is the problem - it takes ages to check each frequency. I've tries using SDR console data analyser to see a 2D plot of what is going on so you can then pick out the interesting time/frequency especially for M-S - but with more that an few Gbytes it takes a long time to load. So 10 mins of recording takes about 2 minutes to load. You then have to set the mode and manually drag the cursor to open out the bandwidth for wideband FM. But with 10 mins worth of signal the resolution isn't likely to be good enough to spot short MS bursts - but it's worth exploring.

Recording a 10 min period around the hour and half-hour to catch station announcements would be a good compromise and on the OIRT band you can capture nearly the whole band. Say 66.0 to 73.5MHz in one fell swoop.

Rgds
David
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

Damien Read
Posts: 76
Joined: 17 Nov 2014 20:20

Re: New computer for SDR's - some questions

Post by Damien Read » 13 Mar 2015 23:24

Of course, it depends on what your budget is first, All my PC's E8400, Q9650,i5 2450, and i7 4790K will run the Elad.
Of course, l wouldn't expect to be multi tasking using the E8400 cpu.
My main point being, you don't need to go crazy, if you want basic operation.
Certainly you shouldn't be experiencing stuttering files.
Get your Pc running up to speed first, give it a defrag, and try to find out what programs you have running in the background, you would be amazed at the amount of programmes that hog your cpu power.
Sadly there isn't a totally correct answer, just advice, depending on your needs.

Damien
Stourport on Severn

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