10 Common Mistakes Made With Software Defined Radio 

#timecodes 0:50 10 what software 3:20 9 device driver 4:05 8 coax type & losses 5:21 7 signal bandwidth 6:27 6 time of day 8:00 5 modulation type 9:08 4 high gain setting 9:52 3 low gain setting 10:29 2 cheap & cloned SDR's 11:44 1 antennas

This was a great video! I have been into SDR slightly more than causally for a few years but recently started to really get into it. I had not heard of SDR Console. Your channel is literally my favorite for tech content. Thank you and hello from the USA.

My first antenna, as a 10 year old SWL, back in the stone age, was a crocodile clip on the metal dial of our old GPO telephone. Actually worked better on top band than a 100 foot long wire. Miles of overhead cable. The end was probably close to some my contacts QTH ;)

Even after more than forty years of being a radio pro and a radio ham, there is always something new to learn. I have had SDR# on my PC for some time but it seems to continually stop working. Upon your recommendation I've installed SDR++, and so far so good. It also seems that Amazon sent me a genuine RTL-SDR V3. Thanks for the video.

Very good advice. I've been listening for years and learned a lot via trial and error. Good point about listening to different bands at different times of the day. I know a lot of people turn on a radio or SDR and then get discouraged but it was only because they chose the wrong band at the wrong time. A little reading would help, but some don't want to read a lot, they just expect it to work like an FM radio.

Absolutely great video for those diving in. Ive shared this on some of my social channels.

Lots of good points here, thanks. Regarding making your own antenna, for ADSB on 1090 MHz, I made a quartter wave ground plane antenna by soldering bits of 18 swg wire to a SO239 socket. 69mm is about the right length. This fits nicely into the end of a length of PVC water pipe to use as a mast.

I one hundred percent agree. An antenna is the most crucial part of a radio setup. I am looking forward to hearing more information about SRRplay's "SDRconnect."

I was deeply involved in this hobby for years and am thinking of getting back ...GREAT ADVICE. Thanks for sharing!

great vid as always. i had a discone antenna masted on my shed attached to an sdr and laptop with software decoding. I now have a campervan and use similar setup but with slidewinder portable getting very greater results. for extra £50 quid antenna is very important. keep up the great work.

Very good video. There's many things you mentioned I wish I knew when I started with SDR

Thank you for this! I’m one of those just starting and learning what I need. You video in my opinion did a great job of giving me a great comprehensive look at the hobby!

Most excellent presentation with great presentation style. It's always good to encourage and help new starters in SWL and Amateur Radio.

Very informative and professional as always. thanks 📻

Great vid. The only thing I would add is to maybe grab a frequemcy reference table. In the beginning, I didn’t know there are dedicated / recommended frequencies for various modes. I blindly turned the dials hoping to hear things in the wrong mode.

@14:20 My father was an EE who worked primarily in power generation control. His buddy was an EE who worked primarily in radio. The friend told me that all I need for an antenna was a bicycle wheel and some knowledge. The "some knowledge" part got me every time. Never could meet that standard.

Thanks, I've had mine a few weeks and this was still a great reminder of things to keep in mind. I'm still using my dipole from the RTL-SDR kit, and I can get a quite a bit with it being on a second floor in a fairly quiet area on a hill.

In my opinion the DIY aspect of an antenna has always been one of my favorite aspects of the hobby. As a kid I used everything from metal window frames to chain link fencing just to see what I could get. Now I have far too many books on antenna design and theory. Great video keep up the good work!

Brilliant, thanks, this was pitched at the right level for me and I learnt a lot :)

Very comprehensive video, there's a lot of things I wasn't aware of here

These SDR's need band-pass filters for the band your listening too and a variable RF signal attenuater . You'd be amazed how much better the SDR behaves not having to deal with outside frequencies.

Love Love love it very informative just what I needed. Thank you .Colin

I'm just getting into amateur/ham radio so all of this is a lesson for me. I'm on the 13th floor of an apartment building in the UK with pretty good all round clear views. I am looking to install a quarter wave antenna upon my window ledge but obviously I need to be mindful of my neighbours as well. I already have some RG6 and RG59 coaxial cable with impedance of around 50 ohms so I am part of the way there getting my equipment

You do a fantastic job explaining necessary info without resorting to crazy faces or "fake news" headlines. Really good basic to intermediate instruction. I knew most of the topics covered but it was still entertaining to listen and I picked up some new tips and info too. THANKS for your excellent and highly professional work.

Great list! Keep up the great content.

I'd like to add that decoupling the SDR from the USB power and its noise makers, and the antenna from the other noise makers in the house is essential. Many people use multiple turns through #73 or 75 mix (or Type J) ferrites to reduce the RF noise coming through the USB power wires. I have seen noise going all the way in to the VHF bands. This will provide a much better signal to noise ratio, especially if you're using small loops such as the YouLoop.

On the coax side of things, the shorter the better. I bought an RX-888. It has a USB 3.0 and its extremely power hungry. I put the SDR 1 metre from the antenna and used a powered USB extension cable (15 mtrs) to get back to the PC. After doing some experimentation using a 15 metre length of LL400 and the USB cable, the difference was staggering. Having 1 metre of coax at 1200mhz and sending the data over the 15 metre USB extension, compared to the 15 metres of coax and 1 metre USB cable, there were signals on the long data cable that were just not there on the long coax. It wasn't only on the upper freq either. The whole bandwidth of the 888 was so much better. The SDR lives in the ceiling space, its dry. More than one way to skin a cat. Liked and subbed. Keep up the good work.

Some good points. Starts at the Antenna and downhill from there.

Thank you for the video and the advice, I'm fairly new to basically all of radio frequencies, and I'm trying to learn, I'm just having a hard time, but I'll get it eventually.

Thanks. Useful info I needed to hear

No mention of a magnetic loop antennae. I use one for my Airspy HF+. Works really well for me at least in a high rf noise area when listening across the pond from the east coast.

wow that was really useful i have learnt something today, thanks

I use Sharp and ++. Thanx for the SDRuno. Going to d/l it now!

Amazing content. Simple, informative, higly entertaining.

Great video and explanation. With reference to antennas: - I have an end fed half wave (flower pot) tuned to 123Mhz. The strange thing is I get really strong reception on SSB as well as air band. I purchased a Tecsun AN-48X and found it to be worse than ever and just amplified more noise. I put up a long wire and got SSB signals but still not as good as the flower pot. Including the antenna windings the total length of wire from the loft to radio is 45 feet. I'm wondering is this acting as a long wire. Incidentally I use a Uniden UBC125XLT and a Tecsun H-501X on the same antenna made with Ultraflex 7 coax. Before I fork out on an outside discone your comments and advice would be gratefully accepted. Thanks again for the videos.

Very well done, just the aspect of direction. A whip is omnidirectional and also frequency sensitive by its length. One could use a Yagi, but that has its frequency limitations too but will concentrate receiving in one direction, actually attenuating signals from other directions. . A log periodic is probably the answer for the higher frequencies, as it is directional and can handle a wider band of frequencies. But you will need a system that can turn it around to face different directions. (And maybe tilt from horizontal to vertical too) Now we have polarization too, vertical polarized means you need your Yaggi to be verticle position, the whip is vertical, a mode used in preference to horizontal. . Then we have balanced to unbalanced to balanced, the yaggi is balanced and most radios outputs are unbalanced. Here we use a "Balun" a 1/2 to 1/4 wavelength coax, connected between the two points on the folded dipole of the Yaggi. Many prefer a small transformer, air core or ferrite core. Coax is joined to earth, and one of the dipoles ends. On HF frequencies you can make a antenna tuning unit, which basically just adds length to the antenna by putting a coil in series, or shorten the antenna by purring a small cap in series. I suppose one can google the details of all these things. IMPORTANT - You will only need to do this if the stations you want to listen to are very weak. Antennas are the only thing you can tweek, I loved the machanisms I had to make to make my 12 element Yaggi wiz around in 360 degrees. It also could tilt up and down and twist it from verticle to horizontal. Hope this gets you started on making antennas.....lol

Thank you very much for all your wisdom.

Its Crazy How I Learned And Figured All This Out By Myself, Like, 90% Of All These Things You Said I Have Figured Out Myself, Now Looking back, Damn, I needed To Watch Some Ytb Videos Like Yours :D

You've got a lot of great information here! Thank you...🇺🇸 😎👍☕

very informative summary, thanks

Vary good video clearly put well done. Point of intrest for people who are able to have a bit of garden space. Build a doublet antenna with wire feed it with 450 ohm ladder/window line use either a Balanced tuner or a 1 to 1 balun and coax to a unbalanced tuner atu. To tune the antenna adjust atu till strongest recived signals can be seen from the sdr signal strength meter or put in a coax switch and use a noise bridge to tune the doublet antenna. Also to reduce electrical and static equipment noise put two 8 foot earth spikes in the ground about 13 feet apart and join the two together with 22mm copper water pipe. Reason for this is due to high frequency skin effect of signals and noise. Connection of earth to the earth stud or metal is case of Computer / and sdr devices be careful not to generate earth loops. All things earthed only 1 earth wire to a earth block then a large single run to the earth spikes. A 66 foot doublet with a good atu NB spend money on a good manual tuner. pay you back in hours more enjoyable time. Will tune from meduim wave to 600 mhz quite well. Pleanty of youtube on this tech. Also if you want to try it out a 12 point rotary switch to ceramic caps of lots of different values between centre of coax and earth near atu to help load capacitance on Atu can help values to look at from 1pf to 2000 pf is a good starting point. Hope this helps As a side point use a cheap old am reciver cb air band etc to source your own equipment noise and reduce your chances of getting electrical noise just hold it close and if the am reciver gose nuts that's noise ferrite beeds type 31 are good. Have a good day ps if useing coax and balun keep the coax as short as possible less the better it will be

ADS-B and HFDL/shortwave hobbyist here. My own experience is that building my own antennas ended up costing more for a poorer-performing antenna that purchasing ready-made ones once you factor in the price of components, tools, test equipment etc. They're fine to play with if you already have a well-stocked junk box and workbench, otherwise just buy the antenna that you need and you'll save money in the long run, and get better results too. That being said, it's fun to build antennas and no one can have enough tools and spare parts!

Very well done.Kudos

Wonderful video. Very useful tips, especially for new SDR enthusiasts. Regarding coaxial cable, one should not overlook the RG-6 75-ohm coax used for cable TV and satellite dish systems. Although most SDR receivers are designed for 50-ohm impedance, and ideally used with 50-ohm coax, the slight mismatch of impedance between a 50-ohm SDR and 75-ohm coax would be negligible, especially for receiving. Quad-shield RG-6 cable is relatively inexpensive, is easy to work with and purchase connectors for, and has very low loss characteristics well up into the GHz range since they are designed for satellite signals. Also, coax cable can be used to construct DIY co-linear antennas for UHF operations such as ADSB. There are multiple examples for making coaxial co-linear antennas cut for specific UHF frequencies, that can be as effective as commercial co-linear antennas for a fraction of the cost. Again, thanks for the great video. Ken -- WBØOCV

Thanks for the Information on SDR I have been running dragon os focal about a year and all the software works out of the box don't have to do a bunch of trying to install packages to get it to work, very good for Amateur radio a lot of that SDR software I could not get to work on other Linux os.

15:20 12.5khz is the channel width used for FM in V/UHF. The bandwidth of our signals is approximately 16 kHz: max deviation +/- 5 kHz, maximum transmitted audio frequency 3 kHz (calculated with Carson's rule). It is convenient to reduce the received bandwidth for weak signals. 73s.

Very good and informative video ! Thanks ! By the way you did not mention dipole antennas ? Why ?

Great advice 👍👏👏

of interest with antennas, I have successfully used a 1090mhz antenna, to receive and decode stuff from 88mhz to 500mhz with no issues including flex, pocsag, dmr, p25, acars

One of the key specifications for SDRs is the number of bits in the ADC (resolution). This controls the potential dynamic range of the receiver. SDRs have wide-open front ends (no or minimum filtering), This means they have to deal with very strong signals at the same time as the weak one you are trying to listen to. Cheap SDRs might have 8-bit resolution, medium-priced SDRs might have 12-bit resolution. That's a 16 fold improvement in dynamic range. And, some high-end SDRs have as much as 24-bit resolution. That's a 65,000 fold increase in dynamic range. You will have a much better experience if you buy more bits of resolution/dynamic range!

I have been away for a while, stumbled onto your channel. I will return frequently.

Great video!

Good video! Why not loop antennas? Small space and great performance.

I have bought a Chinese clone of the SDR dongle named SDR ver.1.0.1.4 based on MSI chips with 2 DIP-Switches (8 & 4 pins) and one SMA joint (the dongle without a case). It works perfectly under SDRUno and SDR Console and there were some problems with SDR Sharp & SDR Angel due to drivers.

I take exception with one of your recommendations. Placing your antenna in the garden seems a good way to use the space for a 2nd task, but in operation it gets in the way when it comes time to harvest vegetables. Even small tractors have a hard time working around an antenna. It complicates weeding as well. It is far better to use an area outside of a garden.

Thank you!

SDR Console is the best software for my cheap, tiny RTL dongle. I wish it would support DAB and I wish there were a way to get rid of that stupid waterfall (but luckily you can narrow the window). Thanks for the hint !!

Helpful video! Great! Looking for SDRuno for Ubuntu but can't find anything.

My tram 1411 discone works good for a 2nd antenna. Highly recommend it for anyone on a budget

So with regards to antenna and coax. I was about to possibly make a mistake thinking receive only really didn’t require much in the way of feed line or a proper resonant antenna. One thing I have found even working HF is that on a given frequency, just tuning in, matching the antenna most always make the receive better. I know it is to protect the radio but has the benefit as mentioned. That said, I am not sure using a given antenna matching device is safe with the SDR, maybe you wouldn’t mind responding to that aspect. Second since we are not transmitting and are not worried about db loss in the coax why does one need to say run LMR 400 or even better to the antenna. I have considered shielding and possible parasitic CMC reaction from any coax. But the receive antenna is going to be somewhat exposed to TX RF no matter what. I will be placing a receive overload device in-line before the SDRduo. Your thoughts will be greatly appreciated. Your presentation was very well though out and professional.

can you use modern tv cable for the antenna as today's digital tv and cable modems can run in the ghz range? or even with the right adaptor connect to the tv cable?

Thank you! RWB

Thanks for the great content! Your channel is what got me into SDRs and what a wonderful hobby it is 😉. I have a rookie question to ask if you don't mind. I currently have two RTL SDRs, one is the Nooelec Smartee and the other is the Smartee XTR. As I understand both have the same chipset but different tunners (E4000 vs R820T). The Smartee with R820T was the first one I had on my computer and recently I received the Smartee XTR (E4000). Do I need to install different drivers for the XTR or I just simply need to set it differently in the software (offset tunning and IQ correction)? Reason for asking is that at the moment I am picking up far fewer signals with the E4000 with the same antenna setup and don't know why Cheers!

Hi As a Ham operator I love sdr Loved it so much I went out and got the IC 7300 - I use a long wire that is about 120 feet or meters connected to a 600 OHM latter like that connects to a 50 OHM PS239 0 UHF female This way I run a LMR 500 I found it so much better with this low loss but you really don't have to worry about if your just receiving. I don't know what they got that would work for the PC TX software wise so hitme back if you know the best free software i can get for QRP 5 watts would be great 10 even better because like you I understand how to use a AMP LOL but you really have to worry about SWR once you get above 20 watts or even 10 1/1 is not hard to get if you have a antenna analyzer I use a manual one I love it! well that's all for now hope your enjoying the hobbie KG5CUO

One thing i have found out is that usb cables need to be powered(active) if you want to or need to use an extended length over 5 mtrs .I was going to purchase an sdr play unit but i need it to be placed in my workshop outside 50feet away from my pc in the house as i dont want to re run my coax cables into my house .

Is it okay to attach two different antennas for two different bands, but connect them both to the same coax cable? Or, does each band antenna need its own coax run?

Great timing! I was literally attempting to configure a NuElec on Windows just this afternoon! On that note, does Zadig change anything on the SDR itself, or does it simply add drivers to Windows? Your help would be appreciated!

GREAT VIDEO for EVERYONE!!!

Antennas: You also have to think about lightning protection (e.g. for an antenna in the garden).

Hi, Great video. I am trying to use an AirSpy HF+ Discovery using SDSharp for my IC-7300. However, I keep getting the message "Port is not available" for the omniRig Sync. Do you have any suggestions on what mistake I am making? Thanks in advance.

Great info! Thanks!

To get better frequency accuracy, try to find the freequency offset.

A magnetic loop might also be of great interest for people who don't have much space to install an antenna

I plan to mount my dual band antenna on a channel mast roof eve mast. Can I attach a 2nd antenna to the mast example discone and use the existing lmr400 coax for both antennas? Or do I need a second coax ? I won’t be using both antennas at the same time. Some type of splitter? Ty

You mentioned lack of space, so what would you recommend for a small, wide band RX antenna?

Can you please reccomend a book that is specific enough but adequate for novice users that deals with - antennas, coax cables, filters, gain, resistance etc. - the bottom line here is what equipment to use for which frequencies. How to scan propperly etc.

Hi love your channel full of useful information for SDR beginners can you do a review on the new Deepsdr-101 receiver I have one but would love to see more indeph reviews

As a total n00b, I made an even more basic mistake: trying to see how my RTL-SDR picked up my own radio transmissions by transmitting from an HT about 3 feet from my antenna. It died immediately and got rather hot. As we say in the MIdwest, ope!

Thank you

some years ago i used an RTL dongle from an DVB-T usb-stick for listening to ATC radio using SDR#. No i am trying to set it up all again, but i cant receive ATC radio. However, radio broadcastimg (FM) works fine. any hint what i am doing wrong? thanks

As a total beginner, I must admit I still find the antenna bit the most impenetrable.

I really appreciate your video, Im new to SDR. What cable do I need for 1.420 Mhz for hydrogen line radio telescope?

I believe all 2m ham radio is wide band actually. Narrow will sound super quiet and cut. This may be a USA thing vs the UK.

recently got the rtl took me three days to get the drivers installed properly. I then got a basic antenna mostly what I pick up is fm radio and digital signals. Did hear a bit of morse. haven't gotten around to figure out the digital most say get two devices. I don't want to throw anymre money at this anytime soon.

What about non dongle SDR like an actual radio for someone starting out such as an ATS-25X1

Does SDR++ support Raspberry Pi4 with Radioberry pi hat?

Is there an easy way to use the existing antennas in my cellphone and feed that input to my SDR software?

What software should I use with Mac?

Ur da best!

Which sdr and sdr software should I get for my MacBook Pro

Why are these things "mistakes"? The title of this should be "10 Tips for SDR Enthusiasts"

I think, with high gain you can't damage your SDR reciever. Because gain doesn't matter of the circuit which is operation on sameway regardless to gain settings. Of course, you can damage your reciever by high wattage RF in your near radius and that is more important how you can damage your reciever. But IDK if it is possible. If there is someone who know more and tell me about how gain can cause circuit damage i will be pleasured. :)

I wish there was more information about the yardstick one

I want an sdr that decodes digital radio, digital tv sound, cw, rtty, pagers and satellites

Can SDR sharp be used on a mac?

The most important mistake that wasn't mentioned: Avoid proprietary soft- and hardware! Instead look for radios with open hardware interfaces, resulting in free (as in libre, not as in free beer) drivers that run everywhere and software that is also free (also as in libre and not as in free beer)! If you don't care about your freedom to learn how things work, your freedom to modify and experiment... then get the whatever you want, I don't care. But don't complain if you can't do the more advanced things with it. I personally think, using free software is a absolute must in software defined radio! With every physical radio, you can disassemble it an look inside how it is built and you can modify it. Even if it is a one chip solution, some people grind down chips layer for layer and put them under a microscope to reverse engineer them. Actually polish them down micrometer for micrometer and the microscope is a electron microscope, because the structures you look at are often smaller then the wavelength of visible light. With software defined radios move all the "magic" into software. If the software isn't free, you have to reverse engineer it which may rival the complexity of grinding down a chip and reverse it under the microscope. Something most people can't effort. So you need access to functional blocks, their source code and documentation. Then playing with software defined radio becomes as easy as assembling a kit or building something from an existing design. With proprietary software *only*, the radio hobby would die, because the design of most radios is nowadays a software defined radio. Fortunately free software and free hardware designs exist. Some Examples of free Hardware Designs: Ettus Research USRP: The Company Ettus Research started with the goal to build a low cost SDR that everyone can use, especially with GNURadio. But since then, their hardware became more and more capable and also more expensive. Their Hardware became a fundamental tool for the development of high bandwidth mimo systems like 5G and also used by the military for signals intelligence. They are now owned by National Instruments and their Radios have become prohibitively expensive (You have to decide if you want to buy a new luxury car or a radio). But they still release Hard- and Software designs and support the free software projects involved. And there are various Clones available. ADALM Pluto: The company Analog Devices wants to sell ICs and a good way to do it, is to create open and inexpensive educational material that can be used to teach the next generation of engineers, when these start working for companies that build stuff, they use what they know and this is how to sell chips. ADALM stands for Analog Devices Advanced Learning Module, it is a very inexpensive but highly capable software defined radio. It contains a runtime-reconfigurable FPGA with two physical ARM CPU Cores that run Linux. The HDL source for the FPGA and all drivers for Linux are available, the result is that it just works and that people have built firmware for special purposes. Clones of the Hardware exist, some are even better then the original (Better TCXO, additional SMA connectors für RX2 and TX2, Metal case). The HackRF One: Because the USRP was too expensive and something less expensive was needed to allow people to reverse engineer and audit wireless devices, the HackRF Project was started. It is also a completely free design and comes with free software to support it. The above mentioned SDRs have one thing in common: No filters, a completely open frontend from ~1MHz to ~6000MHz, so you might easily overload them with strong out of band received signals. So a bandpass filter for the received band is advised. And on the TX side, it is also unfiltered and a low pass filter for the band used is always needed if you want to transmit. Another Example of free Hardware Designs are all the OpenHPSDR designs. OpenHPSDR is a Project that created a lot of modules from ADC / DAC boards, amplifiers, filters, power supplies and so on. Control and transport of I/Q data happens via Internet Protocol over Ethernet. Based on this Design (Especially the protocol used over the network), many other SDR Transceivers were created. The ANAN or the Hermes Lite 2 or Charlie 25 are good examples of derived hardware designs. Non-Free Hardware Design: RTL2832U based USB TV-Receivers, probably the most popular SDR ever. It was actually just a proprietary/undocumented USB TV receiver, but a developer of linux drivers managed to discover a mode where the receiver starts sending I/Q data over USB. Now we have cheap entry level SDRs for everyone. But I don't consider it free, it was just a happy accident. Of course it is now very well supported by free software and the hardware is so cheap, it would be wrong to not mention it. Some Examples of free Drivers: UHD: The software to communicate with USRPs (and Clones). libiio + libad9361 (and many more): The very modular driver framework to communicate with ADALM Pluto and similar Analog Devices hardware. rtl-sdr: The software to communicate with RTL2832U based USB TV-Receivers. hackrf: The software to communicate with the HackRF One. The OpenHPSDR based Radios work over Ethernet / Internet Protocol, there is no direct Hardware access needed. The same can be true for UHD and libiio, if the Radio has a Network Interface. The rtl-sdr software comes with a tool called rtl_tcp which also allows to make a SDR accessible over the network. Hardware Abstraction Layers osmosdr: It makes different types of SDRs available with a single programming interface. You can add new hardware support to it and all programs that use it, can immediately access the new hardware. The user normally has nothing to do with osmosdr, except when some program uses it, you have to see if your hardware is supported by osmosdr and if it is, it is also supported by the program that uses osmosdr. Unfortunately the osmosdr project isn't very active maintained. It works for its intended purpose. SoapySDR: Basically the same idea as osmosdr but written in C++ and actively maintained. It supports everything that is supported by osmosdr (because it can use osmosdr) and it has SoapyRemote, which makes all supported Hardware available over Network. Programs that use osmosdr or SoapySDR: gqrx: A simple AM/FM/SSB receiver application. sdr++: A newer receiver application, more demodulators (it was mentioned in the video) sdrangel: A transceiver application, you can receive and transmit AM/FM/SSB and various other modes. Programs that use the HPSDR Protocol: linhpsdr: A simple transceiver program for OpenHPSDR based radios. pihpsdr: The same but optimized for the raspberry pi. Programs for SDR rapid prototyping and frameworks: GNU Radio: It is a large library of SDR components, building blocks. Filters, Modulators/Demodulators and input output modules, signal generators and so on. They can be used when you program something from scratch. But they can also used by the tool named "gnuradio-companion" where you drag and drop those blocks on a workspace and create connections between them. It is like building a radio from minicircuits modules, you get filters, mixers and so on and connect them. Pothos: Basically the same idea as GNU Radio, but more focus on rapid prototyping like gnuradio-companion and less a library of SDR modules. The SoapySDR Project is part of it. liquid-dsp: A library full of common digital signal processing routines to build software defined radios. libvolk: A companion project for gnuradio, it contains common functions used in digital signal processing, like multiplying large arrays of numbers. But these functions have hardware specific optimizations. Everything on a lower level is like winding your own coils and transformers to build your own radio. This is where I could list common programming languages like c, c++, python and so on. But this is already a wall of text. ;-)

👍👍

I notice on RTL-SDR's have issue with most 3.0+ usb port hosts.

How can get RTL SDR in india

is it allowed to send death threats on amateur radio freqs?