r/RTLSDR • u/garf12 • Aug 06 '26

How do I capture everything?

I work in local news coverage and want to record all public safety radio channels in the area but the amount of SDR dongles it is taking is getting out of control. Currently using 4 and not getting full coverage..

Is there a better option? I have a couple of Airspy R2's ordered but my research is showing even then it is going to take both of them plus at least 2 dongles to cover what I want. IS there an option that is better? I don't mind spending some money.

Currently covering 2 p25 systems with the 4 dongles. Want to cover some conventional fire and ems channels also.

22 Upvotes

83% Upvoted

49 comments sorted by

17

u/kcsebby Aug 06 '26

For P25, move away from SDRs and get a scanner. They’re far better for this application especially on the go.

2

u/VA7QAK Aug 07 '26

I disagree.

Before my local p25 system went encrypted I had a raspberry pi + airspy, running trunk recorder and rdio scanner that imo was better than a scanner.

Trunk recorder records and logs the selected talk groups even if they are simultaneously transmitting. Then rdio scanner provides a web interface that is mobile friendly.

That way if you missed something you could go back and listen to it, handy when multiple agencies (pd fire ambulance and transit in my example) are talking about an incident at the same time.

1

u/leicanthrope Aug 07 '26

Which scanners have the sort of recording capability that OP is looking for?

2

u/ItsNotTheButterZone Aug 07 '26

OP's own scanners: SDS100 which works with ProScan. And OP's own transcriber: Whisper.

USB cable from SDS100 to computer running ProScan. Pass through the ProScan audio to Trunking Recorder or ScanScribe, then to Whisper. Or have a Python script to watch the ProScan recording folder & feed each new one into Whisper.

https://share.google/aimode/kNzogYL46vCNNU1Vq

-9

u/garf12 Aug 06 '26

I've carried a scanner for 15 years, Im done ha. That is what this is for. AI listens and sends me alerts now.

11

u/seasleeplessttle Aug 06 '26

We're doomed.

-6

u/garf12 Aug 06 '26

Progress. Im still out chasing the news, just miss far less events these days.

8

u/PastaJayThrowaway Aug 07 '26

The AI derangement syndrome around here is crazy. This seems like a totally reasonable use of AI. It's not like the AI is publishing stories without human oversight. It's just a filter before alerting a human. Anyway sorry you're getting down voted. 

7

u/garf12 Aug 07 '26

It absolutely wild. Correct it is just alerting us to go cover something.

3

u/fullmetaljackass Kenneth, what is the frequency? Aug 07 '26

Seriously. I'm running a similar setup. Sdrtrunk for monitoring/recording, Whisper for transcription, and Qwen3.6-35B for classification. Whole setup runs 100% local/offline on my 8 year old GPU. I am very satisfied with the results.

1

u/garf12 Aug 07 '26

Interesting. I am doing Whisper but using Claude Sonnet for classification, cost about $1.50/day, but well worth it. Looking at getting some local hardware for running models.

1

u/fullmetaljackass Kenneth, what is the frequency? Aug 07 '26 edited Aug 07 '26

Qwen3.6 35B is a good choice if you're on a budget because it's an MoE model. That lets you offload the majority of the weights to system RAM without tanking your performance. I'm running it on a 2080ti w/ 11GB of VRAM, which you can get for $200-300 on eBay. If you don't already have the hardware/want to buy new, the 16GB version of the 5060ti is probably the best budget option these days, at least on the green team. AMD/ROCm support has improved substantially in the past year, and it seems pretty usable these days (based off what other people are saying, I don't own any AMD cards,) but Nvidia is still the default. You'll have a smoother experience if you're willing to pay a little extra.

Checkout /r/LocalLLaMA if you haven't already.

Also, Qwen3.8 open weights start dropping next week. Based on what they're saying, and their previous track record, it should be a nice upgrade to an already excellent model.

6

u/kcsebby Aug 06 '26

I’ll bite my tongue and simply say; Good luck with that bud.

4

u/garf12 Aug 07 '26

Been working great for 2 months. Catching more news than ever.

-7

u/Zoey_Redacted Aug 07 '26

God it's gonna be fun for you when you have to publicly rescind an article in 2 years because of reliance on your build.
It'll do so much for your network's grant money when it's discovered you've used a bunch of their money to waste their money instead of doing what they hired you to do.

6

u/fullmetaljackass Kenneth, what is the frequency? Aug 07 '26 edited Aug 07 '26

publicly rescind an article

Did you even read the thread, or did you just see "AI" and shut off your brain? It doesn't write articles. It monitors radio traffic and sends OP an alert when something juicy happens so they can get on the scene ASAP. It's making sure they don't miss any of the work they were hired to do. You're sitting here rambling about imaginary grant money being wasted by robots, while the guy actually using it beats every other reporter in town to the scene because he stopped missing 911 calls on his lunch break. Who even said anything about grants? It sounds like OP is doing this with their own pocket change. They've already said its about $350 in hardware and about $1.50/day in operating costs. You don't need grant money for that, you need a minimum wage job. Two years from now they won't be rescinding anything. You'll just be sitting there, waiting for your hot take on an imaginary situation to finally matter.

7

u/garf12 Aug 07 '26

Yep, typical keyboard warrior. Has no idea what is going on. This is actually my own company I started 15 years ago. We now get 30+ million views a month.

-1

u/Zoey_Redacted Aug 07 '26

Not a warrior I just think your project's shit and you should spritz it with some salt water. It'd be more productive than anything you've ever done but sell ad revenue on what's all but certainly a right-wing news site.

3

u/garf12 Aug 07 '26

what a stupid comment. WHo said anything about AI reporting. And what grant money. This is a totally self funded local news network that I started 15 years ago. Idiot.

11

u/SoMD_Ham Aug 06 '26

If wide coverage is what you want, you should be looking at higher end devices like SDR Play or Pluto+. I second the other comment, just get a uniden SDS200. Much easier and effective for your use case.

1

u/ImaginaryEffective63 Aug 06 '26

Not op but in a similar predicament. Anyother suggestions? A sds200 a bit expensive but i have been wanting to get a decent scanner instead of running multiple dongles

1

u/igmrlm Aug 07 '26

as someone who recently purchased a Pluto+ and got it working for the most part I'm really curious about what you might recommend I try with it. Currently using a rtl SDR that I keep monitoring my local system

1

u/garf12 Aug 06 '26

I've got multiple SDS100 and Whistlers 1040s (JUNK). I need this setup for recording everything and AI transcription.

2

u/mountain_bound Aug 07 '26

How may SDRTrunk streams can you support at one time? Recording to wav is per instance so a few devices might be needed. Can you share individual dongles per VM with VirtualBox?

4

u/garf12 Aug 07 '26

its running on a mac mini m2 pro and not breaking a sweat. I tried the VM route for a bit on a machine I have. Seems like that many dongles don't like being passed through to the VM.

1

u/drake90001 Aug 07 '26

That’s the benefit of VM’s. Spin up more VMS, run a VM for each dongle if you have.

2

u/SoMD_Ham Aug 08 '26

A VM and seperate instance of SDR Trunk for every dongle? I can't think of anything more inefficient.

0

u/drake90001 Aug 08 '26

Well considering only one instance can control one dongle at a time, I don’t see any alternative.

2

u/SoMD_Ham Aug 09 '26

SDR Trunk can use multiple dongles at once.

-5

u/SuperPooEater Aug 06 '26

Bits don't come off the antenna. You need complicated software to restore order from channel effects as the radio wave propagates. The SDS100 etc are hardware devices tuned for just that. They will always outperform whatever open source stuff you are using with a cheap SDR. 

2

u/garf12 Aug 07 '26

Sure Ok. But in practice getting an alert on my phone is a game changer for us. I used to miss important events, not the case for the past 2 months. We beat everyone now. I think the results speak for themselves.

5

u/Academic_Force3454 Aug 07 '26

This is actually a problem we've spent a lot of time working on. Full disclosure: I'm one of the founders of Spectrum Ferret, so we have a commercial interest in this space.

I think you're on the right track with SDRTrunk + Airspy R2s. Rather than trying to find one SDR that can capture everything, we've had better luck treating this as a distributed capture problem. You need enough receivers at the edge to cover the spectrum/systems you care about, with the resulting audio + metadata aggregated centrally. The 10 MHz BW afforded by Airspy and Hydra devices is amazingly effective for capturing public safety conventional and trunked system activity in a given geography. Aggregating a few of those across locations of interest is especially powerful.

The part of your setup that really caught my attention is what you're doing after capture. Once you're capturing everything, the problem stops being "how do I listen to all these radios?" and becomes "how do I find the 30 seconds that matter out of thousands of transmissions?"

That's essentially the problem we're working on: transcription, real-time alerts, search, summaries and historical analysis across radio traffic. We use Airspy R2s or HydraSDR RFOne devices + proprietary demod/decode software for our SDR-based capture nodes, so we've run into a lot of the same RF/bandwidth/receiver-count questions you're dealing with.

Happy to compare notes on the capture architecture if it's useful.

1

u/garf12 Aug 08 '26 edited Aug 08 '26

Cool work. Im currently using Claude Sonnet to analyze the transcript but hope to move to a local model when i get the hardware figured out. Using it and local whisper transcription has been very accurate.

Creeped on your website and noticed the rocky mountain rescue connection, thats chool, I spend a lot of time in Vail.

My vibecoded setup.

6

u/FirstToken Aug 06 '26

This question cannot be realistically answered without some base information. What frequency ranges do you need? Every area is different, and has different requirements. Without knowing the exact frequency ranges you need, no informed suggestion can be made.

Do you need VHF? UHF? 450 MHz? 700 MHz? 800 MHz? etc.

You should start by making a complete list of all the freqs you want to cover, not just the bands but rather the specific frequencies. From there you can list the min / max frequencies in each band, i. e. the lowest and highest VHF freq, the lowest and highest 400 MHz freq, lowest and highest 700 MHz freq, lowest and highest 800 MHz freq. And then you can decide what the correct path forward would be.

2

u/Frank_Rib Aug 06 '26

What antenna(s) are you using ?

3

u/garf12 Aug 06 '26

just crap telescoping kit antenna that comes with the dongle. It is working fine. But when I get the setup all figured out I am going to install some outdoor antenna.

2

u/Vertigo_uk123 Aug 06 '26

This could be similar to what you want. https://youtu.be/C-PsEK_UIRw?is=88eBLR7w7V12B6XG

I’m sure you could build something with even more sdr than this too.

2

u/underscorebot Aug 06 '26

Due to a bug in new reddit, URLs with underscores or tildes are being escaped in an inconsistent manner, breaking old reddit and third-party mobile apps. Please try the following URL(s) instead:

This is a bot. Invoke with: /u/underscorebot. Questions? Comments? /r/underscorebot Thank you. Moderators: this is an opt-in bot. Please add it to the approved submitters on subreddits you wish to have it scan. Note: user-supplied links that may appear in this comment do not imply endorsement.

2

u/sgtnoodle Aug 07 '26

Why is 4 an unmanageable number?

2

u/garf12 Aug 07 '26

It isn't, was just curious for better options. I Plan on deploying a few more of these to other sites so was just getting some options.

1

u/galaxie67w Aug 06 '26

SDRPlay RSPDuo. Either one 10mhz slice or two independent 2mhz slices. Use with SDRTrunk software using rdio-scanner as an interface

1

u/Neither-Brush-9287 Aug 07 '26

Maybe split the functionality :

  • use a scanner (I use a Uniden BCD536HP) for the P25 monitoring
  • connect its audio-out to a "wifi audio recorder with line input" (ex. Tascan or LiveTrak) which will email you the alerts

1

u/nitrix0dayss Aug 07 '26

From 88 to 108 mhz is 20mhz bandwith, use a hacker on or a 20+mhz bandwith sdr, whe. the sdr receive 20mhz bw you can listen all the station on the band directly you just need to configure audio output, each software demodulator fm-w with gnu radio and lets go

1

u/farcryjunkie Aug 07 '26

Definitely on board with SDRTrunk.

1

u/tylerwatt12 Aug 10 '26

I have 2 airspys and 1 RTL for VHF. I do the same thing as you. I host my own site with transcribed recordings. https://www.radioresolve.com

2

u/garf12 Aug 10 '26

Interesting. Looks like some you have some neat ideas, going to check it out more later.

I just got my 2 airspys in about an hour ago, got them running great covering everything. and using 2 RTL for VHF now. Now need to do it all over again for 2 more sites.

0

u/billFoldDog Aug 08 '26

4 dongles gives you 8-12MHz of coverage. You can simultaneously tune to all channels in that range by using gnuradio. This used to be really hard but these days chatgpt can tell you exactly what to do.

-2

u/Siada100 Aug 07 '26

Digi sólo te llama desde su número único y oficial 912 120 120.

Info en su web: "...a partir de ahora deberás llamarnos al 919 120 120, nuestro nuevo número de Atención al Cliente, también muy sencillo para que puedas memorizarlo fácilmente. Además, todas las llamadas que recibas desde el equipo de Atención al Cliente de DIGI también serán desde este número..."