Hacker News Reader

Comment by amelius | Hacker News Reader

Is there SDR for the GHz range of signals used by modern equipment?

FWIW, if you have an SDR that doesn't work with the frequency you want to work with, you may be able to use an up-converter or down-converter in front of the SDR to shift the frequency enough to work. There are ones like the Ham It Up[1], etc. that may be appropriate depending on the circumstances. Or you could possibly build your own.

[1]: https://www.nooelec.com/store/sdr/sdr-addons/ham-it-up.html

You can get an AD9363 clone of the USRP b210 online for like, 300 USD?

The AD9363 stock is only supposed to be 325mhz to 3.8ghz but stuff like the plutoSDR which uses it manages to get the transceiver all the way from 70mhz to 6ghz like the more expensive AD9361 used in the real USRP B210s

Benefit is you can transmit stuff too, not just receive unlike the RTL-SDR which is RX only

Is there anything like this that can go down to 15 MHz or lower? including transmit and several analog modes of modulation USB LSB NFM WFM AM CW at least

If I understand what you're saying, you can do any modulation scheme with sdr, it doesnt depend on the model

Groovy. Are there any limiting factors such as processor speed and what is the best software that does it all on Linux? I have no idea what ratio of magic smoke is in the software vs. ratio of magic smoke is in the hardware.

The output of a usb radio like this is a set of IQ values which is the raw data from the ADC. The amount of values (samples) you get is device dependent and also limited by your interface. The RTL SDR 4 over usb can do up to 2.4-3.5MHz. The ADC on that device is 8 bit so you will get two 8 bit, IQ numbers per sample.

You can tune into remote SDR’s people set up to work with this data without having your own device or download recordings others have made.

It is this raw sample data that you then demodulate according to whatever scheme required on the PC side.

A great resource I found was pysdr.org. I had absolutely no background in RF and very little python experience but that guide explains everything from the ground up from how the IQ samples are physically generated and read in an antenna, all the modulation schemes you mentioned, and how to code useful things with the various devices. No affiliation but a great resource.

There are levels to this that can get very expensive very fast depending on what your intent is, and how comfortable you are with programming various FPGAs.

HackRF One can go up to 6GHz ($400 new or $100 on alibaba for a similar device). Any higher frequency than that you'll be paying thousands.

Yeah I dont know any SDR above 6GHZ but also other than mmwave 5G I also dont know much radio that is above 6Ghz in general

Quite a few radar systems are in the 8-10GHz range and satellite communications just above that. The general idea when using a SDR for these things is to have a separate frequency converter & amplifier at the antenna feed itself, then have an intermediate frequency <6GHz fed via cable to the SDR. Tends to be much easier and cheaper this way.

Here you go, from the US perspective:

https://www.ntia.gov/files/ntia/publications/2003-allochrt.p...

Looks cool, except it uses USB2 which seems limiting in view of bandwidth.

480 Mbps is plenty for low GHz signals. 1GHz gives you 20MHz to play with, which turns into about ~100 Mbps max. A 6GHz signal pulling out all the stops will give you at ~1.6Gbps, but if you're dealing with data that extreme you're barking up the wrong tree with a cheap SDR like the HackRF.

for anyone reading this actually interested, just FYI an improved model "HackRF Pro" is due for release in the next month or so, is backwards-compatible, and is what will come in at that $400 price tag.

years ago, there used to be a very abundant market for used or chinese clone HackRF One units, but i haven't been able to find any these days.

"modern equipment" uses all KINDS of different frequencies, so that statement doesn't mean anything :/

Why not, if you want to address all those frequencies you need the highest capability, so GHz range not MHz range.

Not true at all.

FM wideband is something like 88-108MHz.

108-137MHz is a lot of aviation traffic.

7-144MHz lots of long range DX.

Then the 144-148 amateur band.

151-154 Multi Use Radio Service

433MHz has all kinds of sensor data from the world around you.

462-467 Family Radio Service (FRS) / General Mobile Radio Service (GMRS).

900MHz area has different types of beacons, cameras, etc.

1090 for Aviation beacon ADS-B

For other freqs you can often use an upconverter or downconverter to hit the freqs you need.

Examples: https://www.nooelec.com/store/sdr/sdr-addons/upconverters-do...

Reply on news.ycombinator.com