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szatox Advocate
Joined: 27 Aug 2013 Posts: 3460
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Posted: Mon Nov 25, 2024 2:22 pm Post subject: Hams, any opinions on hackrf? |
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I'm mildly interested in radio com, I've been occasionally looking at SDRs on the market and thinking about what I'd like to do about maybe joining the hobby, and I found this one device which _maybe_ would be a good start for me, but I'm not quite convinced and don't want to spend 500$ on a fancy paperweight, which is roughly what I'd need to cough up for the device and antenna.
So, hackrf.
+ wide frequency range, 1MHz - 6GHz.
- 8 bit ADC, I was surprised it can be this small and still work
- rx amp is said to be being easy to fry
- sold as a radio lab test equipment, it's unclear if it's only for legal reasons, or because it overall is a bad receiver with a very wide frequency range as its only redeeming quality
Does anyone here know this thing?
Would it make a scanner suitable for getting my feet wet? Is it sensitive enough to pick up signals form hams, weather broadcasts and so on?
Could I use it to snoop in on emcomms in case of disasters, or something like that? I mean, 500$ is 500$, would be nice if it had a second purpose besides being a new toy... _________________ Make Computing Fun Again |
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Banana Moderator
Joined: 21 May 2004 Posts: 1760 Location: Germany
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szatox Advocate
Joined: 27 Aug 2013 Posts: 3460
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Posted: Mon Nov 25, 2024 6:31 pm Post subject: |
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That rtl doesn't go anywhere nearly as high into microwave spectrum, but man, I could get it so much cheaper it actually is a tempting suggestion.
What feats have pulled using this dongle?
I know I could google it, but there surely is a world of difference between anti-proffesionals (because money flows in the opposite direction) calling themselves amateurs and newcomers, so I can't really expect to get the results from brag stories born on the internet. _________________ Make Computing Fun Again |
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eccerr0r Watchman
Joined: 01 Jul 2004 Posts: 9828 Location: almost Mile High in the USA
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Posted: Mon Nov 25, 2024 10:53 pm Post subject: |
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Question is what exactly do you want to monitor?
Most microwave stuff is encrypted, I doubt many people are using FM or SSB or something that's not digital/QAM/CDM/... on microwave frequencies. Most of that stuff is on cellphones and stuff and that's really short range, encrypted, and illegal to monitor. Yes there's some satellite but most of that's also encrypted.
Emergency comms are trending to P25 and encryption on that is part of the standard.
Or are you just planning to listen on the amateur bands? Or what's left on analog/unencrypted?
I was thinking about getting an rtl-sdr but really haven't found a good use statement for it. Sure I could monitor anything I wanted but not much I really want to hear these days... Only thing is perhaps monitoring my power meter transmitting updates, but not much else. Otherwise I'd probably at most use it for a waterfall display for HF perhaps.
What I do need to do is get CAT control working on my hf rig... put in the UART but it's not working :( _________________ Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching? |
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szatox Advocate
Joined: 27 Aug 2013 Posts: 3460
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Posted: Tue Nov 26, 2024 1:51 am Post subject: |
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> Question is what exactly do you want to monitor?
I don't know, I'm new to this business. I want to see what's on air.
Amateur bands sound good, meddling with wifi with its 40, 80 and 160 MHz wide channels is definitely out of the question; I'm not willing to pay the price of a rig big enough to capture this traffic (and regular wifi adapters are better suited for that job anyway), but bluetooth should be doable on pretty much any SDR reaching into 2.4 GHz band.
What else is there? Weather broadcasts? LoRa? Even if I'm unable to decode contents of some transmissions, I might still be able to figure out what kind of transmissions they are and maybe say something about the source.
Who knows, maybe hunting anomalies would be interesting. I won't know until I try.
The thing I liked about a radio scanner going up to 6GHz is that it should cover pretty much all frequencies with a practical use; I doubt there's anything going on in higher bands.
What's up with those encrypted emcomms? I saw some info about training camps for hams regarding participation, so it looked like it should be available for civilians too, even if you're required to get a license before you transmit anything. Or is it another case of different countries doing things differently?
Regarding legality, I'd rather focus on technical stuff here, like setting expectations for the signals I might be able to find and receive and what are those devices capable of (if you have any experience with them), since what's legal varies from country to country and needs to be sorted out locally anyway.
Fortunately I don't have to obey USA's legislation. Unfortunately, politicians here are just as good at wasting paper.
Did you know in my country it's technically illegal to own a hammer? It is a weight on a stick, which makes it legally a weapon, and if the weight is wider than the stick, it must be registered and you need a permission to own and use it. I mean, nobody will bother stopping you in a hardware store, but according to the weapons law it is _technically_ illegal. _________________ Make Computing Fun Again |
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Ralphred l33t
Joined: 31 Dec 2013 Posts: 661
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Posted: Tue Nov 26, 2024 2:54 am Post subject: Re: Hams, any opinions on hackrf? |
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szatox wrote: | I'm mildly interested in radio com | First thing, learn how to turn an "old car radio" in to your own "personal, one mile radius" pirate radio station*.
Once you have this down, and understand how to "manually boost the range", "*why you should use a digital tuner", and turn "Szatox FM" into "Szatox FM (Now in Stereo!)", you'll have a solid grounding in the original ideas behind "radio comms" - with this under your belt, all the other questions will answer themselves (or at least furnish you with the knowledge of how to effectively express your end goal), the same as "I've never run Gentoo before, why should I run it on my server?" answers itself after running it for 6 months on your daily driver laptop would do the same.
It's a fascinating yet "relativity easy" topic to understand once you scratch the surface, and there is so much you can do in the $10 range to build your knowledge and understanding before you go buying "new toys", like talking to bored airline pilots and irate air traffic controllers... |
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Banana Moderator
Joined: 21 May 2004 Posts: 1760 Location: Germany
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lars_the_bear Guru
Joined: 05 Jun 2024 Posts: 529
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Posted: Tue Nov 26, 2024 10:56 am Post subject: |
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eccerr0r wrote: |
I was thinking about getting an rtl-sdr but really haven't found a good use statement for it. Sure I could monitor anything I wanted but not much I really want to hear these days... Only thing is perhaps monitoring my power meter transmitting updates, but not much else. Otherwise I'd probably at most use it for a waterfall display for HF perhaps.
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That's been my experience. I don't have a clear need for an RTL-SDR, either, but it was cheap enough that I bought one anyway, just to see what it can do.
The problem I have with it is that all the signal processing is very CPU-intensive, and my computer overheats. So, other than running some sample applications, I haven't done a lot with it. Works fine under Linux, though, with GNU Radio and others.
BR, Lars. |
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szatox Advocate
Joined: 27 Aug 2013 Posts: 3460
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Posted: Tue Nov 26, 2024 2:49 pm Post subject: |
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> First thing, learn how to turn an "old car radio" in to your own "personal, one mile radius" pirate radio station*.
Some boys want to be astronauts, some want to be be astronomers. It is a good path to take, I'm just not quite sure I want start with with jumping all the way to the other side, especially since there is a thing I need completed before I can give my full attention to building something else from scraps.
> Here are two ready to use images for raspberry which include a lot of software to tinker with. It should give you an idea what software is available
Thanks, sounds good, I happen to have a spare Pi4, kinda wanted to turn it into a NAS, but this may actually be a better use for it.
> The problem I have with it is that all the signal processing is very CPU-intensive, and my computer overheats. So, other than running some sample applications, I haven't done a lot with it. Works fine under Linux, though, with GNU Radio and others.
How did it fare in terms of sensitivity and selectivity for example? Or did you just plug it in, saw that it talks to the computer and went back to a more specialized rig? _________________ Make Computing Fun Again |
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lars_the_bear Guru
Joined: 05 Jun 2024 Posts: 529
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Posted: Tue Nov 26, 2024 3:22 pm Post subject: |
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szatox wrote: |
How did it fare in terms of sensitivity and selectivity for example? Or did you just plug it in, saw that it talks to the computer and went back to a more specialized rig? |
I didn't test extensively, but it seemed broadly comparable with my Icom. The RTL-SDR (well, probably GNU Radio) actually offers better control over bandwidth than the Icom, if you can take the time to fiddle with it. So there might even be a better control of selectivity. But I live in a radio black-spot -- at the bottom of a valley, and with a stack of interference. It's on my to-do list to take all this equipment to the top of a hill and test it properly, but I never seem to get the time.
To be fair, the RTL-SDR was about one fiftieth the price of my Icom. It blows my mind that it works at all. It certainly works better than the price would suggest.
BR, Lars. |
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eccerr0r Watchman
Joined: 01 Jul 2004 Posts: 9828 Location: almost Mile High in the USA
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Posted: Tue Nov 26, 2024 4:43 pm Post subject: |
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The encryption on a lot of police/fire/etc. communication is mainly to prevent interference over making sure data isn't intercepted. Some of this emergency communication that happens over encrypted radio is also simulcast over the internet to prove that they aren't doing it for hiding communication versus ensuring interference free (mainly to prevent tricking first responders of fake emergencies.)
That is not to say amateur bands are still being used for emcom, after all ARES is all that along with the usual public service uses of amateur radio. And in the USA pretty much you're allowed to listen all you want, just don't decrypt if you're not the intended target of the communication (and of course no encryption on amateur bands.)
There are other things that may be interesting. A lot of weather satellites transmit their imagery unencrypted and you can receive the photos directly without waiting for it to show up on local news. But that doesn't show up in the microwave frequencies, it's like slow scan TV where it takes a while to receive a frame. (note that this differs from radar imagery which needs to be computed from on ground transmitters and you probably can't generate an image directly.)
This also differs from the USA NWS broadcasts that happen over FM. These are audio broadcasts and nothing special about them. Similar to the time transmitters like WWV.
The other aspect of (amateur) radio is that the expectation that you'll be transmitting. If all you're doing is listening, that's not really amateur radio... and transmitting is regulated mainly to prevent tragedy of the commons. _________________ Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
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szatox Advocate
Joined: 27 Aug 2013 Posts: 3460
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Posted: Tue Nov 26, 2024 5:59 pm Post subject: |
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> To be fair, the RTL-SDR was about one fiftieth the price of my Icom. It blows my mind that it works at all. It certainly works better than the price would suggest.
Good to know. It is a vague answer, but it does work as a gauge.
Yeah, it blows my mind that an 8 bit adc is enough to pick any signal at all. Makes me wonder at what frequency do they sample that signal to make up for low spacial(?) resolution.
> The other aspect of (amateur) radio is that the expectation that you'll be transmitting. If all you're doing is listening, that's not really amateur radio... and transmitting is regulated mainly to prevent tragedy of the commons.
Yeah, I get that part. I might make it the second stop.
Thanks for details explanation of the other things, that should make a decent starting point _________________ Make Computing Fun Again |
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zen_desu n00b
Joined: 25 Oct 2024 Posts: 30
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Posted: Tue Nov 26, 2024 8:26 pm Post subject: |
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I got a RTL-SDR just to dig deeper into LoRa stuff. I have a variety of LoRa transceivers from different manufacturers and of different specs and wanted to see if I could setup a radio to sniff stuff for more debugging.
I was never able to get anything to actually decode the LoRa broadcasts, but I was able to see them.
For ~$30 a RTL SDR is a great toy at the least and is essentially plug and play on Gentoo, you just need to get something like sdrpp. _________________ µgRD dev
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