What is a better SDR Interface to the Computer?

[N5RWJ]

Ethernet or USB-2 ?

[KE5JPP]

Ethernet or USB-2 ?

Both have their advantages and disadvantages.  As for Ethernet 10 BASE T is really too slow, 100 BASE T is slightly slower than USB 2, and 1000 BASE T is definitely faster.  1000 BASE T is wasted if the computer does not have a very high end processor to take advantage of the increased data bandwidth available.

Gene

[N5EG]

Ethernet is better if you want to network multiple computers with one SDR radio (or even multiple radios). However many of the 100-BASE-T consumer grade Ethernet switches do not achieve anything close to 100 Mb/s throughput; some are in the 15 mb/s range.  This could cause you problems if you need higher actual rates approaching 100 Mbps. A google search may lead you to sites that can advise as to your particular switches actual throughput.

If you just want one radio to talk with one SDR radio, USB 2 gives you a good chance to actually achieve throughput, especially if you avoid USB hubs and connect one computer directly to one radio.

-- Tom, N5EG

[WS4E]

I am not sure where your going with this, since most SDR 'interfaces' are the I/Q lines to a sound card....the sound card is important, and is usually PCI/PCI-X, USB, or Firewire.  USB usually uses the most CPU, while PCI and Firewire are better performing. 

I use a ASUS D1 PCI Sound Card, and a EMU FA-66 Firewire sound box, and both provide full 192khz SDR performance.

[KE5JPP]

I am not sure where your going with this, since most SDR 'interfaces' are the I/Q lines to a sound card....the sound card is important, and is usually PCI/PCI-X, USB, or Firewire.  

I don't think he is asking about old outdated sound card based SDRs like the Softrocks, Genesis, LD-1, SDR-1000, etc...  He is asking more about the modern direct sampling SDRs like the Perseus, QS1R, RF Space, or Winradio Excalibur.  I would not say that "most SDRs" use I/Q to the soundcard either.  The modern direct sampling SDRs provide bandwidths much greater than 192 kHz.  The old fashioned sound card QSD based SDRs are limited in bandwidth by the common sound card rates of 48 kHz, 96 kHz, and 192 kHz.

Gene

[W6RMK]

the answer to the question is the classic "it depends".

If it's a SDR approach where you're basically feeding bandlimited raw samples to a PC for processing, then USB is probably easier.  If it's an approach where you have some "smarts" in the box between sampler and interface, or where you might want to have multiple PCs and multiple sample streams, Ethernet is going to be more appropriate.

If it's an SDR (a'la Flex) where you are leveraging inexpensive high volume gear (audio interfaces), then you want whatever the inexpensive audio gear uses, today, that's USB 2.  Who knows where it will be in the future?  Thunderbolt? USB3? something new?

[N5RWJ]

Ethernet or USB-2 ?

I think in the future, you will need Ethernet?

[KE5JPP]

Ethernet or USB-2 ?

I think in the future, you will need Ethernet?

USB 3.0

Gene