Software Defined Radio Hack Chat

What's in your dongle?

Wednesday, September 18, 2019 12:00 pm PDT Local time zone:
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SDR guru Corrosive joins us for the Hack Chat on Wednesday, September 18 2019 at noon PDT.

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If you've been into hobby electronics for even a short time, chances are you've got at least one software-defined radio lying around. From the cheap dongles originally intended to watch digital TV on a laptop to the purpose-built transmit-capable radio playgrounds like HackRF, SDR has opened up tons of RF experimentation. Before SDR, every change of band or mode would need new hardware; today, spinning up a new project is as simple as dragging and dropping a few blocks around on a screen, and SDRs that can monitor huge swaths of radio spectrum for the tiniest signal have been a boon to reverse engineers everywhere.

Corrosive is the handle of Harold Giddings, amateur callsign KR0SIV, and he's gotten into SDR in a big way. Between his blog, his YouTube channel, and his podcast, all flying under the Signals Everywhere banner, he's got the SDR community covered. Whether it's satellite communications, aircraft tracking, amateur radio, or even listening in on railway operations, Harold has tried it all, and has a wealth of SDR wisdom to share. Join us as we discuss the state of the SDR ecosystem, which SDR to buy for your application, and even how to transmit with an SDR (hint: you'll probably want a ham license.)

  • Hack Chat Transcript, Part 4

    Dan Maloney09/18/2019 at 20:40 0 comments

    RF will never cease to baffle me...

    jmcservv1:15 PM
    ah ok as for aerial i use a discone antenna buit from pipe fittings and stainless steel rods

    Signals Everywhere/KR0SIV1:15 PM
    Put it on a service monitor/sepctrum analyzer and feed a noise source into one side while changing the length of the open coax and you'll see the notch frequency change

    Joyce1:15 PM
    RF will always be magic to me :)

    Signals Everywhere/KR0SIV1:15 PM

    James Finch1:15 PM
    @Dan Maloney I think it's like optics too... there's some wave particle duality think going on. :-)

    What kind of bandwidth does a filter like that have?

    Signals Everywhere/KR0SIV1:15 PM
    There is always more to learn and I love it

    Max-Felix Müller1:15 PM
    It's amazing. I got the opportunity to get a basic look into it at university :)

    James Finch1:15 PM
    think = thing

    Joyce1:16 PM
    And I am glad to be able to practice RF

    Joyce1:16 PM
    and communications systems in general :D

    Signals Everywhere/KR0SIV1:16 PM
    @Dan Maloney I'm honestly not too sure, it's not a lot but it's enough that we've used them in commercial situations before to notch out a nearby interfering frequency on our repeater input

    Well, I mean, a notch is a notch, right? Should be pretty tight, I'd think.

    Signals Everywhere/KR0SIV1:17 PM
    Yeah it's tight I just don't recall the exact bandwidth

    James Finch1:17 PM
    Read like a good scenerio to demonstrate in a video and/or write-up.

    Signals Everywhere/KR0SIV1:17 PM
    it'll notch out a 25khz wide FM signal so I'd say at least 30khz

    Max-Felix Müller1:17 PM
    Mathematically it's just the one frequency

    Signals Everywhere/KR0SIV1:17 PM
    I should measure it some time

    James Finch1:18 PM
    Maybe can incorporate into the RTL-SDR way cost effective toolkit as a way to measure? Maybe compare with a better performing device to see capabilities?

    Signals Everywhere/KR0SIV1:19 PM
    @James Finch you can use a noise source, RTL and an RF bridge

    Signals Everywhere/KR0SIV1:19 PM
    Planning to do a video on that too

    @Signals Everywhere/KR0SIV - If I can put my $0.02 in and request a video on what you can do with an SDR and a digital scope to troubleshoot and design filters, etc. I think that's what you were mentioning before, but just wanted to plug for that. I'd find that super-useful

    Signals Everywhere/KR0SIV1:19 PM


    Tuning an HF Antenna with an Airspy, SWR-Bridge and Noise Source

    Over on his blog Anders J. Ørts has created a good writeup showing how he used the combination of an Airspy SDR with SpyVerter upconverter, SWR-Bridge and a noise source to tune his HF dipole for the 40 meter and 20 meter bands.

    Read this on

    Oops - missed @James Finch while I was typing. Same thing basically

    Signals Everywhere/KR0SIV1:20 PM
    @Dan Maloney for sure, I want to do one filters and such, I may not have the work space to build a filter right now but I can take a ready-made cavity filter and tune that to show how the tools work

    Sounds awesome!

    Signals Everywhere/KR0SIV1:21 PM
    It's crazy how much you can do with SDR these days

    James Finch1:21 PM
    Yeah... the Airspy HF+ with Spyverter looks good (maybe better in some freq ranges) compared to the SDRplay RSP1 and SV1AFN DC-55MHz upconverter.

    Signals Everywhere/KR0SIV1:22 PM
    Heh I feel like I'm going crazy sometimes, I honestly have more than 50 ideas I could rattle off right now for videos I want to do (and have parts to do most of them) it's just a lack of time that keeps them back sometimes

    James Finch1:22 PM
    @Dan Maloney We need the redundancy... it's like a survey without the website.

    Signals Everywhere/KR0SIV1:22 PM
    @James Finch Suposedly the RSP1 has true DB measurement which would be extra useful

    James Finch1:23 PM
    I still need to...

    Read more »

  • Hack Chat Transcript, Part 3

    Dan Maloney09/18/2019 at 20:07 0 comments

    Joyce12:53 PM

    James Finch12:53 PM
    Way more complex when getting into the microwave range. Just watched a Keysight presentation noting how every section of a circuit in a system has to be studied to understand the affect... where I perceive is like an antenna basically so not to cause reflections, impedance mismatches, losses, etc.

    Signals Everywhere/KR0SIV12:53 PM
    Speaking of filters the next one I need is going to be for broadcast AM, I need to get into VLF soon

    Signals Everywhere/KR0SIV12:54 PM
    @James Finch very true, as you go up in frequency even the PCB material can affect the signal/circuit

    Joyce12:54 PM
    Well, every part of a RF transmission system has to be matched to achieve optimal performance

    Max-Felix Müller12:54 PM
    @Signals Everywhere/KR0SIV any thoughts about Software Defined Antennas (for hobby use)?

    Joyce12:54 PM
    and yeah, it can get tedious quick

    Signals Everywhere/KR0SIV12:54 PM
    @Max-Felix Müller What do you mean software defined antennas?

    James Finch12:54 PM
    @Signals Everywhere/KR0SIV Totally, the demonstration was just a via causing the losses around 20GHz.

    Joyce12:55 PM
    microwave is really finicky :P

    Signals Everywhere/KR0SIV12:55 PM
    @Max-Felix Müller or I suppose you're asking what antennas to use with your SDR?

    Max-Felix Müller12:55 PM
    @Signals Everywhere/KR0SIV antennas that can be tuned by software to have specific directionallity and/or use different frequencies

    Joyce12:55 PM
    A lot of it is still magic to me xD

    anfractuosity12:55 PM
    like ?

    anfractuosity12:55 PM
    or more beamforming?

    Signals Everywhere/KR0SIV12:56 PM
    Generally you want a tuned antenna if you can, 2m antenna for 2m, L band antenna for L band etc..

    However for general reception you could go with a discone antenna

    dmoisan12:56 PM
    Or phased-array like radar.

    Signals Everywhere/KR0SIV12:56 PM
    The antenna is the MOST important part of your radio system, doesn't matter if the radio cost $10M if your antenna is crap it's not going to work

    RichardCollins12:56 PM
    I am picking up Spanish AM/FM? stations up around 500 MHz on the RTL_SDR V3? Any idea how it gets mixed in. My Spanish is not good enough to tell which station. In terms of algorithms, it would be nice to have standard ways to identify strong interference sources, frequency drifts, sferics (lightning), and identify stations location and information automatically.

    Joyce12:56 PM
    beamforming is already done by an array of antennas; if you can vary the phases going to the antenna elements; you can "steer" the array electrically

    I use a discone on my FlightAware SDR and I find it to be a poor performer. Could be the long and lossy feedline, to be fair.

    Signals Everywhere/KR0SIV12:57 PM
    @RichardCollins It could ben a strong harmonic mixing or intermodulating

    Signals Everywhere/KR0SIV12:57 PM
    I'd tune around to see if you can find which station it is in the broadcast band

    dmoisan12:57 PM
    There must be an FM nearby--very nearby--to get images at 500 MHz.

    Signals Everywhere/KR0SIV12:57 PM
    then look it up with the FCC to get the location

    Signals Everywhere/KR0SIV12:57 PM
    and power

    Dan12:57 PM
    While talking antenna questions, I just typed this one up, n00b question incoming:

    Great chat, thanks for it. Quick question. Wondering what the term is for what I ran in to this past winter.

    I had (still use) a cheap 800mhz Yagi antenna and at this point I had it distributed to many (6 or 7?) RTL-SDR v3's all monitoring the same (800mhz) P25p1 system via UniTrunker/DSD. I'm sure this distrib/amp thing was not the best choice but it worked: And this sytem worked for a good long while but sucked in that it was LSM system with UniT and bad quality.

    Well this past winter I stood up a...

    Read more »

  • Hack Chat Transcript, Part 2

    Dan Maloney09/18/2019 at 20:05 0 comments

    BSA Secure12:31 PM
    @RichardCollins I'm playing with Viasat Surfbeam 2 modems and their TRIA's (Outdoor units) that supports Input (RX) Frequency 18.3 to 20.2 GHz

    Output (TX) Frequency 28.1 to 30.0 GHz. I'm getting them on various none-ebay portals for really cheap. Drop me DM and I will share with you my wiki. Or join Signals Everywhere discord where I'm pulling out my RF knowledge.

    IRC12:31 PM
    [Arsenijs] Discord? Got an invite link?

    Signals Everywhere/KR0SIV12:31 PM
    @Chris Capobianco You don't need an LNB, that range is covered by most RTLs, I'd recommend a helix antenna on a dish

    Signals Everywhere/KR0SIV12:32 PM

    Absolutely agree. But that dog won't hunt around here - people here have a bit of a blindspot when it comes to law enforcement. Even will ban you now if you complain about encryption. Kinda nutty.

    Signals Everywhere/KR0SIV12:32 PM
    yeah encryption is a very hot button topic

    Signals Everywhere/KR0SIV12:32 PM
    I hear there are a few groups planning on breaking it and presenting at Defcon, we'll see if they manage but if so it'll change the landscape

    James Finch12:32 PM
    Totally need to monitor the monitors for sure. Let's see... representative government is sworn with oaths and like President Lincoln stated... for the people and by the people.

    RichardCollins12:33 PM
    @BSA Secure Thanks I will contact you after this

    James Finch12:33 PM
    More than nutty, seems like a blatant compounding and concealing.

    Sheridan-Tech12:33 PM
    This is probably a dumb question, but are these chats logged? Can I just load this URL later and grab all the chats from this page?

    Signals Everywhere/KR0SIV12:34 PM
    @Sheridan-Tech I believe @dan

    Maave12:34 PM
    there will be a transcript posted after

    Signals Everywhere/KR0SIV12:34 PM
    welp that didnt work :p

    Signals Everywhere/KR0SIV12:34 PM
    Yes it'll have a transcript

    Chris Capobianco12:34 PM
    @Signals Everywhere/KR0SIV Thanks, Much appreciated!

    @Sheridan-Tech - I post transcripts right after the chat.

    Sheridan-Tech12:34 PM
    Ok. At this link? Or found elsewhere?

    I'll post a link when it's live.

    BSA Secure12:34 PM
    Just keep in mind, that by observing encrypted traffic you can know of stream is voice transmission , drone-high-bandwidth video footage or small telemetry. Its like listening train that is passing by - you can know if its empty or is full of heavy elephants (even with oracle padding)


    Hack Chat Transcript, Part 1 | Details |


    Read this on Hackaday

    BSA Secure12:35 PM
    may be not know but rather assume

    James Finch12:35 PM
    My opinion is we need to hack relevant U.S. Jurisdiction (State, District, Tribe, Territorial and Nation) Constitutional and Statutory Law into the Public School's from kindergarten on up ASAP. Post 1960's change in being able to be admitted into the bar with a J.D. was a root cause from my observations.

    Sheridan-Tech12:35 PM
    thank you

    Signals Everywhere/KR0SIV12:35 PM
    Very good point @BSA Secure that's true of most digital modulations.

    Once you have listened for a while you get an ear for things and you can quickly determin what type of modulation it is and often if it contains data or not

    Signals Everywhere/KR0SIV12:37 PM
    Looking back at transmit capable SDRs I'm pretty excited about DVB-S for digital amateur television

    Max-Felix Müller12:37 PM
    @Signals Everywhere/KR0SIV I started listening to some FM stations using an RTL SDR but I'm not sure really where to go from there...

    James Finch12:37 PM
    Prior to the 1960's I think most had a basic Ten Commandment fundamentals to counter claim and defend Rights... and like Yale was the last to admit into the bar with a Bachelors of Law.

    Maave12:37 PM
    Any recommendations...

    Read more »

  • Hack Chat Transcript, Part 1

    Dan Maloney09/18/2019 at 19:35 0 comments

    OK, everyone, it's noon here in the Pacific time zone, so let's get started. Today we have @Signals Everywhere/KR0SIV to talk about software-defined radio, which I can't believe we've never done a Hack Chat about.

    @Signals Everywhere/KR0SIV - Welcome! Can you kick us off with a little about yourself and how you discovered SDR?

    fernando.gil joined  the room.12:01 PM

    hackadaze joined  the room.12:01 PM

    Signals Everywhere/KR0SIV12:02 PM
    Sure thing @Dan Maloney

    So my name is Harold Giddings although most online know me as Corrosive or my amateur callsign KR0SIV

    I originally got involved with SDR when the RTL drivers were originally modified from old TV Tuners to an SDR platform.

    This was years ago when I was still active on IRC and once I saw these things in action. I was officially addicted

    Chip Standifer joined  the room.12:02 PM

    Signals Everywhere/KR0SIV12:03 PM
    I'm currently employed as a commercial radio technician and so thankfully I get to have radio fun most days even when I'm not playing with an SDR (which I still find excuses to use at work)

    martin-diy joined  the room.12:03 PM

    DK McGrath joined  the room.12:03 PM

    Bernie Dodge joined  the room.12:05 PM

    RichardCollins12:05 PM
    What SDRs are you using now, and what software do you use?

    Signals Everywhere/KR0SIV12:05 PM
    Software Defined Radio is really what got me back into radio. I take my amateur exam shortly after getting into SDR.

    It was like opening an entirely new world being able to look at the radio spectrum via the waterfall rather than scanning individual channels.

    haz62 joined  the room.12:06 PM

    IRC12:06 PM
    [Arsenijs] should work now (ignore this message)

    Signals Everywhere/KR0SIV12:06 PM
    @RichardCollins Currently my primary daily drive is still the RTL-SDRv3 from the blog however I have a large plethora of SDRs these days. My favorite SDR client software would have to be SDR# however, I make often use of CubicSDR and SDRConsole as well as when transmitting... SDRAngel

    motardido joined  the room.12:07 PM

    RichardCollins12:07 PM
    Do you have particular "targets" or frequency ranges, or just browsing generally?

    Signals Everywhere/KR0SIV12:07 PM
    My primary SDR for transmit has to be the PlutoSDR because it was affordable, has a good housing on it and is of course full duplex

    James Finch12:08 PM
    Totally awesome the visual representations of what you first hear on the radio (or maybe other sensor stimuli too)... then see in other ways to identify, qualify and quantify.

    Signals Everywhere/KR0SIV12:09 PM
    Frequency ranges really depend on what I'm doing. Generally I like to play around in the SW/HF bands as well as looking for digital stuff in the commercial end of the 440 MHz range as well as 800-1090 for P25/trunking/ and ADS-B

    Seth12:09 PM
    I can't wait until lab-grade spectrum analyzers are as cheap as SDR dongles ;)

    Signals Everywhere/KR0SIV12:09 PM
    Satcom is also a big thing of mine so I'll often be playing in the L-Band around 1.5ghz

    Joyce joined  the room.12:09 PM

    Joshua Conway12:09 PM
    Have you ever come across unencrypted 'sensitive' data? If so, how did you handle it?

    anfractuosity12:09 PM
    for satcomms do you need a dish, also what kind of data do you pick up from them?

    James Finch12:09 PM
    The PlutoSDR hack looks nice, thanks for sharing that.

    BSA Secure12:09 PM
    I'm keeping my setup simple and cheap by using RTL-SDR's... until I've decided to extend my knowledge and play around wide bandwidth Ka-Band satellite links that and bought LimeSDR (after getting WAF .. Wife Approval Factor. Now .. everyday I'm learning from Signals Everywhere community so I can dive deeper in RF "Hacking".

    Signals Everywhere/KR0SIV12:10 PM
    @Joshua Conway I do sometimes come acrossed sensitive data.. The key is simply not sharing it, if I do a video that contains such data I'll blur it out (such as my decoding...

    Read more »

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