Anyone using software defined radio?

I've studied the product offerings every few years for past dozen years. Always wanted to buy one. It's the ulitmate DIY method for doing whatever you want with radio waves, as well as other parts of the spectrum. But so far nothing has become popular for ease of use. Your link seems similar than that, but if you have experience with this stuff and you can point me in the right direction I'd be super grateful.

 

Like spread spectrum? CDMA? Or something else?

 

Hard to find a transceiver these days that's not an SDR - but most of my activities lately have been in the 3-50Mhz range tinkering with digital. I do have some of the ChiComm tri-banders which I have used when the Wx gets a little bumpy but they're part of the "C" and "E" in my 'PACE' plan.
GMRS and Meshtastic are in my 'to do' list.

Tread Carefully!
"Some" of the 70 MHz to 6000 MHz spectrum is already...um 'well regulated.'
I seem to remember something about encryption being frowned upon when I was getting licensed, and 'Sad Hams" have been a recurring theme lately in post disaster comms.
IYKYK.....

 

Chinese stuff will cause fires

 

In the US, Part 97 prohibits "messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein".
There are obvious carve outs - such as WiFi, car alarm systems, LoRa on the 33cm band (900mHz) and some private business class licensed sets.
Private business band radio can be 'quasi-encrypted' if you get a permission slip from Big Brother.

Stealth is binary.
It works all the way or it doesn't - all the way.
The "D" in 'SDR' stands for digital, obviously but it also means that whomever (whatever) is hoovering up those ones and zeros just has to be good at math to determine that somebody is singing off-script - and (just guessing here) there are 'some folks' in the Huntsville that ARE good at math.

The trick would be to do whatever it is that you're trying to do without being 'interesting' to the government or some Barney Fife Sad Ham type out there that's looking for an excuse to dig that boolit out of his front pocket.

 

The BATF doesn't have the resources to go after a "black" rifle world either - which is why you can buy a Glock Switch for a few bucks, or a full auto lower for a little bit more.

HOWEVER (comma!!!!!) they do hammer the heck out of the ones that they catch!!!

The FAA has three distinct advantages over the BATF:
(1) Radio waves go quite a ways further than sound does.
One of my current projects involves using a WiFi chip to optimize my HF antennae and to test propagation paths with WSPR (amateur radio software) - Wikipedia.
IIRC we're talking about using 100-200 milliwatts to send a 50-bit message hundreds or even thousands of miles.

If you want to make an illegal suppressor out of a [redacted] or a [redacted] and light up a 55-gallon drum with a rifle that's been modified by [redacted] it's [redacted] - then you only have to worry about anyone within earshot - pun nearly unintended.

(2) The FAA uses a voluntary monitoring system (not just Sad Hams) in addition to civil serpents.

(3) The Military and other Government entities have a vested interest in monitoring suspicious transmissions - and a lot more assets than the FAA.

 

Please post your experiences with your purchase to this thread...

 

One of my long ago bosses, back during his youth, bailed out of a pirate ham station just minutes before FCC agents swooped in to bust those still there. Though their primary sin was exceeding power limits. By a lot.

Somewhat ironically, after I took my pewter parachute and various business units closed locally and consolidated elsewhere, one of the surviving business units was focused on analyzers and software for dot-gov to detect and locate enemy clandestine radio emissions.

Being just a hardware guy aiming for pre-set performance targets, I didn't get very deep at all into the theory. But my impression of spread spectrum communications was that a continuous very low power broadband signal would be much more interference resistant than a short bursty narrow-band frequency-hopping signal. And harder to initially detect.

While many modulation schemes are inherently meant for digital data, at least part of the signal chain path, from before the transmit antenna until after the receive antenna, the actual signal is still analog.

... which helps buoy my remaining company stock.