The younger generation who have ECE/CS degrees love SDR. So does the military and the commercial/corporate radio industry. Some of the older generation frown upon SDR as voodoo magic with too many computer/network dependencies.
There is a general distrust (among older hams) of computer/network technology and especially anything that depends on a non-human (computer program) to modulate or demodulate a message.
For example, you can send Morse Code with a Carrier Wave and a simple switch (on and off) that you built from wood scraps and copper. You don't need an external thing (program, software, device, etc.) to do that for you. So there are less dependencies and in general it is much simpler to reason about and use. When the shit hits the fan, you want simple, reliable things.
The problem is, most humans don't know Morse Code. So they can't decode a message anymore. Thus the reliance on computers and software.
The efficiency gains are hard to argue with as well. You can do things with SDR that would be impossible or far too costly in hardware... Like resurrecting and communicating with a 36 year-old satellite http://www.rtl-sdr.com/rebooting-isee-3-usrp-software-define...
Pretty much. There's a lot of people doing cool stuff over the radio, but the conventional wisdom is that if it wouldn't work in an emergency, you can't rely on it. So while you can rely on computers somewhat, be prepared to jump on SSB/CW/FM in the worst cases (ie, you only have power for your radio, nothing else).
And relying on the internet for anything is an absolute no-no, at least among the emergency people.
Good SDRs have overwhelmingly better performance than all but the most expensive traditional superhet receivers. Even then, the exotic superhet receivers match rather than beat equivalent SDRs. Direct conversion receivers are exceptionally good at isolating weak signals that are close in frequency to strong signals, which is a particularly important trait in amateur radio operation. This is widely understood and largely uncontroversial.
Some amateur SDRs are essentially computer peripherals, but they increasingly look just like traditional transceivers. The Icom IC-7300 was the most talked-about transceiver of 2016; It operates like a traditional transceiver and costs about the same, but has exceptional receiver performance and a host of DSP-based bells and whistles. I expect that many Elecraft customers are completely unaware that they bought an SDR rather than an analog transceiver.
Personally, I would never go back to a superhet receiver. If you use a good SDR for half an hour, you're spoiled for life. Superhet receivers still have a place at the low-end of the market, but they're being slowly squeezed out.
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.
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.
>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.
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).
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.
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.
There is no unity, which is good. Its just like the conversion from AM to SSB or incentive licensing or FM repeaters on 2M in the 70s or no-morse-code licensing or dstar or thru-hole to SMD or rtty to PSK31 or pretty much everything that's ever happened to ham radio ...
Never heard of it. That's crazy. I think its interesting or it'll be the death of the hobby (depending solely on if the participant is personally involved). Its the same stuff looked at differently. We've always all been a fan of that since its start. So obviously I've dropped the docs on me being eligible for QCWA and 3rd gen ham.
I will say as having fooled around with it, latency can sometimes be truly awful which has quite an impact on your normal half duplex operation, ops almost willfully don't understand scalability of the software with bandwidth or real time RTOS desires. Nothing funnier than a PC crash in the middle of a QSO. Ability to "do ham radio stuff" does not necessarily come with basic computer competence, although it often does...
There's a big impedance jump going from "I downloaded HPSDR and it worked" to "I pkg install'd gnuradio and made my own broadcast FM receiver and it worked". Its like using Scratch to write hello world vs porting Emacs to Haskell. The first time you get gnuradio to work its a rush. I imagine the jump from gnuradio to FPGA based boards is similar rush if you can do it. In my infinite spare time...
The other side of this coin is the reason that high-end Receivers don't use SDR techniques in their front end is because the intermodulation characteristics of current A/D converters fall a long way short of conventional Superhet technology.
It will be a long time before an A/D converter chip can equal the performance of a high-level mixer. In fact it will probably never happen, as any advances will apply equally to both technologies.
But yes, I agree with you that few hams are building SDRs. This was my biggest disappointment with SDR. Five years ago I thought that SDRs would usher in a new area of home-brew, but it's evolved into yet another bunch of appliance operators who have little interest in writing the software. So sad, because it's such a fascinating field..
I ignore it as my escape from the daily grind of computing is digging the soldering iron out and building some very minimal kit out of only discrete components. There is something fascinating about extreme minimalism. The fact it transmits and receives is a byproduct of the journey. I'm unsociable enough to confirm a couple of contacts and then build something else.
I have no problem with SDR, it just doesn't interest me. You need a physical connection with the universe sometimes.
Ham here. WT1J. I chat with quite a few hams that run the entire age spectrum. Young and old are into SDR. The older hams use everything from super expensive commercial SDR's that come with rack mountable hardware to Ham Radio Deluxe. The younger hams use RTL-SDR and HackRF along with the pricey gear.
It really depends what you're doing. If you're contesting on RF for example, you'll find younger european hams that have HUGE budgets and build enormous multi-band yagi antenna towers and use very expensive SDR's to monitor the whole band and for excellent RX and signal discrimination capability.
Then you've got the SIGINT crowd that hang out at defcon and they'll generally use cheaper SDR's with bleeding edge software.
The HF band ragchew crowd tend to use boat anchors (old ham radios) with big amplifiers up to legal limit (1.5kw) and hang out especially on the lower frequencies like 7mhz, 3mhz and 1.8mhz. (40m, 80m, 160m in ham speak).
But generally once you get into radio you realize it's less about the base station and more about the antenna.
Do they think it's interesting and cool, or do they reject it for being different and inferior vs. more expensive and sensitive equipment?