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Except for noise. Computers are noisy beasts with spurious radiation (birdies) from DC to UHF. Trying to run a sensitive receiver anywhere near a computer, mean

Except for noise. Computers are noisy beasts with spurious radiation (birdies) from DC to UHF. Trying to run a sensitive receiver anywhere near a computer, means that you have to put up with an unholy amount of interference. And nothing in the design of the SDR can fix this. Old-time hams would never have a computer in the same room as their radios because of this interference. FWIW, I was designing and building my own SDRs ten years ago, and am currently running one of the high-end SDRs.

Tempest1981 10y ago
Are there SDRs where you "remote" the receiver and antenna? Or antenna and low-noise amplifier? I found another site that reviews some units, and mentions the issues you noted: http://www.rtl-sdr.com/tag/sensitivity/ http://www.rtl-sdr.com/tag/sensitivity/
- heywire 10y ago
  I've used rtl_tcp on a raspberry pi before, but that was mostly to get the receiver close to the transmitter (in which case I unhooked the antenna as well).
- jdietrich 10y ago
  >Are there SDRs where you "remote" the receiver and antenna? Yes. The FlexRadio and Apache Labs SDRs are equipped with ethernet. There are numerous standalone SDRs that can be used without a computer. The rtl-sdr isn't really comparable to a proper radio. It is, after all, just a repurposed TV tuner. It's a great little toy for exploring radio, but the performance is exactly what you'd expect for a $20 dongle.
- Johnythree 10y ago
  As above, I have a RF Space NetSDR+ which is connected to the computer via ethernet. So you can remote it via WiFi or any similar networking technique.
madengr 10y ago
It all boils down to shielding. A Rigol spectrum analyzer will never have the performance of an HP due to the lack of EMI mitigation. I have a Flex 6500 with no noise issues due to the computer, then again my RX antenna is 100 feet away.
- Johnythree 10y ago
  Yeah. But I don't think your Flex 6500 tunes above 70MHz, which is where the birdies from modern computers, modems, video cards, and high-end displays are worst. I have a RF Space NetSDR+, and it's wonderful below about 30 Mhz, but there's a horrifying racket on 6m and 2m, and the FM broadcast band is pretty much unusable for weak signal work. I'm playing with a optical link to the top of the hill behind my place. We shall see. I'm surprised that the computer interference issue isn't more widely discussed. I suspect that it's because newbies have no idea of how much of the junk they see on their screens doesn't actually exist. Plus living in city environments they are so swamped by RFI that they think it is normal. Just looking at the screen on the OP's web page makes me shudder. It's a whole mess of computer interference.
blacksmith_tb 10y ago
Does using a long usb extension cable offer any relief for these small tv-tuners? Inverse-square law and all?

Tempest1981 10y ago

Are there SDRs where you "remote" the receiver and antenna? Or antenna and low-noise amplifier? I found another site that reviews some units, and mentions the issues you noted: http://www.rtl-sdr.com/tag/sensitivity/ http://www.rtl-sdr.com/tag/sensitivity/

heywire 10y ago
I've used rtl_tcp on a raspberry pi before, but that was mostly to get the receiver close to the transmitter (in which case I unhooked the antenna as well).
jdietrich 10y ago
>Are there SDRs where you "remote" the receiver and antenna? Yes. The FlexRadio and Apache Labs SDRs are equipped with ethernet. There are numerous standalone SDRs that can be used without a computer. The rtl-sdr isn't really comparable to a proper radio. It is, after all, just a repurposed TV tuner. It's a great little toy for exploring radio, but the performance is exactly what you'd expect for a $20 dongle.
Johnythree 10y ago
As above, I have a RF Space NetSDR+ which is connected to the computer via ethernet. So you can remote it via WiFi or any similar networking technique.

madengr 10y ago

It all boils down to shielding. A Rigol spectrum analyzer will never have the performance of an HP due to the lack of EMI mitigation. I have a Flex 6500 with no noise issues due to the computer, then again my RX antenna is 100 feet away.

Johnythree 10y ago
Yeah. But I don't think your Flex 6500 tunes above 70MHz, which is where the birdies from modern computers, modems, video cards, and high-end displays are worst. I have a RF Space NetSDR+, and it's wonderful below about 30 Mhz, but there's a horrifying racket on 6m and 2m, and the FM broadcast band is pretty much unusable for weak signal work. I'm playing with a optical link to the top of the hill behind my place. We shall see. I'm surprised that the computer interference issue isn't more widely discussed. I suspect that it's because newbies have no idea of how much of the junk they see on their screens doesn't actually exist. Plus living in city environments they are so swamped by RFI that they think it is normal. Just looking at the screen on the OP's web page makes me shudder. It's a whole mess of computer interference.

blacksmith_tb 10y ago

Does using a long usb extension cable offer any relief for these small tv-tuners? Inverse-square law and all?