Software Defined Radio

Let's talk radio. I own a HackRF and I've tried reverse engineering signals from simple devices.

What I'm not happy with is its receive sensitivity. I got better performance with band-stop filters and LNAs but I doubt I can do much better because of the 8-bit ADC it has onboard.

Now I want to try getting signals from LEO and maybe the moon (if it's feasible) using an 8-10 feet dish and I'm planning to upgrade to a USRP (12-bit ADC) or something better. There are USRP B210 clones on eBay for about 600 bucks. However, if I can find something better, I don't mind spending up to $2-5K.

Any thoughts?

Other urls found in this thread:

youtube.com/watch?v=-dSBahyJ32A
w4rp.com/ref/coax.html
blog.icomamerica.com/2017/10/30/is-your-digital-repeater-ham-friendly/
theleggios.net/wb2hol/projects/rdf/tape_bm.htm
lna4all.blogspot.com/2017/02/diy-137-mhz-wx-sat-v-dipole-antenna.html
hfunderground.com/board/index.php/board,3.0.html
hobbybroadcasting.blogspot.com/
github.com/claws/dump1090-exporter
grafana.com/dashboards/768
twitter.com/AnonBabble

So this is how normies feel when they ask me questions.

>Tuning into classified frequencies

You're probably on some watch list just for posting this here.

I don't know much about SDR but the size and type of dish is extremely important.

Solid > Segment > Mesh

Secondly, X-band LNBs for deep space communication are hella expensive. You might be able to get a surplus unit for around $10000 and those will work as good as a toy.

>classified
>frequency
What is this some kind of illegal opinion talk? If it shits it's waves all over the world it isn't classified, fucking retard.

>if it doesn't come from the television its illegal
>2017

Enjoy explaining that to the FCC when they bust your door open.

>Moon

Is this a serious thread or are you retarded?

Do you even know how far away the Moon is? There's no way you can accurately point to an object around it without billions of dollars worth of infrastructure.

radio law people give very little fuck about it unless you start broadcasting. it's not really harmful to anyone, plus important transmissions are coded. you can hear airplanes or maybe sometimes crappy emergency service radios over it, nothing more.


>getting signals from LEO and maybe the moon
>Any thoughts?
yeah, i think i should get something better than rtlsdr. with my shitty old tv antenna i can barely hear satcom things (it's fun to hear though, weird people send their sstv photo albums over it). fuck i'm jelly

i think billions of dollars worth of infrastructure is important when you absolutely have to get this singnal all the time, and just barely hearing something can be achieved in ordinary man budget. i mean, if anyone with twenty bucks in pocket can hear iss, why not aim a bit higher with proper equipment

My ham license provides a good cover for this. Even if I didn't have one, it's still not illegal to listen. Please, kill yourself.

Op here. RTLSDR is actually quite nice, sometimes even better than HackRF for receiving signals on certain bands. I've received signals from NOAA, cubesats and Amateur Radio relays. A QFH antenna works great as an omnidirectional antenna. A Yagi with an Azimuth-Elevation rotor works well as well.

It's quite easy to build custom antennas using PVC or a piece of wood and some copper wires. Antenna Magnus is an excellent software for designing custom antennas which gives you custom radiation patterns.

Hams have received weak signals from Cassini using custom LNBs and a 6 feet. The moon should be far easier than that.

>$20 to listen to ISS

Those YouTube videos are clickbait and fake as fuck.

Any advantage of using PCI-e vs a USB one?

It's perfectly feasible to receive ISS transmissions with an HT

You might be able to see the downlink carrier from distant objects. There's no way you'll get a good enough signal to reverse engineer.

>He thinks he can receive WiFi signals from a $100 Billion dollar space mission using an HTPC

HELL YEAH, radio threads on Sup Forums.

Frankly you're being a little stupid here for not realizing that this isn't one of those things that you're going to be able to just throw money at and buy something prebuilt. You're expected to bring your own filtering to any of these products, from the USRP stuff to the cheapo hobbyist stuff. They're making really good boards (and I do mean 'really good'), but amplification and filtering is on you. Replacing superhet receivers with these awesome ADCs doesn't magically mean that filtering isn't necessary, or that the filters are suddenly cheap.

If you want an upgrade from your hackrf, look into the limesdr mini. As far as filteringr, check HRO and ebay? Maybe their new VHF/UHF SDR transceiver interests you.

Do you have your license? I find it hard to believe someone with a license would not understand how to approach this problem...

maybe Icom's new SDR VHF/UHF transceiver interests you***

youtube.com/watch?v=-dSBahyJ32A

I know I can receive VHF signals from a space station using a handheld transceiver

all you need is pic related and the ability to pump 1.5kW (legal limit) into it

not nearly as expensive as you might think

Child porns just 1s and 0s man!
You can't "OWN" property!
Just eavesdropping!

Any reason why flex radio has not been mentioned yet?

So, pringles can is right out then?

That pic deserves trips.

You can, and there are probably half a dozen elmers who live within 100 miles of you that have personally done it.

They're not fake, and if you think it's amazing you should get into amateur radio, it's just as cool and magical as you think it is. Bounce invisible lights between the atmosphere and the earth, talk to someone crystal clear halfway around the world in Japan or Africa or Finland or Germany. Receive NOAA weather images with a $20 TV tuner from Amazon and an antenna you build yourself. Talk to astronauts on the space station with a simple yagi made out of a tape measure and a $100 VHF radio. You'll never stop being amazed in this hobby.

because OP said $2k-$5k, not $20k-$50k. They don't make anything for VHF/UHF that's geared at amateurs, all their ghz+ stuff is commercial and it has a commercial price.

It's also not a true SDR in the sense of a hackrf and limesdr, etc. No gnuradio support, not really the same thing.

The upper end price is higher than other bands but for hobbyist stuff you can get one for $320 shipped on eBay, not really that expensive. I owned a C-band LNB that cost $800.

Cool, thanks. I have a sdr dongle thingy, and recommendations on a general purpose antenna? Should I try a discone?

Discone is gonna be ok for local vhf and maybe some uhf depending on the size.

Well that depends, what do you want to listen to?
For "general purpose", yeah, a discone antenna is a fine place to start. But i'd recommend picking a frequency for a signal you're interested in and going from there, otherwise you're probably going to be disappointed with the results across the board.

Yeah that's kinda the problem, I don't really know what I'm interested in yet. I know any wide band antenna will be horribly inefficient, but it might be a place to start. What are you guys interested in? What kind of antennas do y'all use?

Are there any sort of LNBs that can do multiple bands? Ka, Ku, C and L?

I built this a couple of days ago for NOAA using barely any tools. I just used a cigarette lighter to soften the edge of the pipe to push the smaller pipe through and then ran wires through.

I was surprised at the performance of such a shitty build.

I made a 4-5 post in a previous thread explaining to an user how to start with sdr and what to read.
Search for it, the name I was using is the same with this post.
If you want to spend money, get a board with ad9361, if you don't have that much money, get one with the ad9364 like the great usrp mini 200.
don't waste your money on h/w you don't know what to do.
I know a bunch of sdr, i have some publications on sdrs, but my main work is on fpgas.
If you don't know how to work on fpgas, bon't go for pcie boards with fmcomms boughterboards.

Is that circular polarization? Currently considering some simple j-poles out of copper tubing to at least get on the air.

Not really. An LNB is a low-noise block downconverter. The point of an LNB is that the signals coming from satellites are extremely high in frequency, 3.5ghz to 4.2ghz for C band, 12ghz to 18ghz for Ku, 8ghz to 12ghz for X, I think you get the picture.

But the portion of the band that you're interested in, say a block of TV channels on a C band satellite, is just a 20mhz portion of that whole band.

Now it wouldn't really be a problem to send the whole band directly down through the coaxial cable to the receiver, if we had perfect coax that did not affect the signal at all. But at these frequencies, it's very difficult to make cables that do not apply a lot of attenuation to the signal (aka loss). see here: w4rp.com/ref/coax.html

So what an LNB does is it downconverts a whole BLOCK of frequencies. So a transponder at 3780mhz is transposed to something like 380mhz, and a transponder at 4188 is transposed to just 788mhz. Much more manageable losses.

So the reason you can't have a combined LNB is that they're on different frequencies. If you used a C band LNB for Ku, you're going to end up with signals that are at very high frequencies and end up with high losses. Likewise, If you use a Ku LNB for C, you're going to downconvert over the signal you're interested in and wipe it out completely.

They do make combined LNBfs, (LNB + feedhorns) that basically have spots for two LNBs so that you can have one dish with multiple LNBs on it. You then send a tone down the line from your receiver, typically 22khz, and there is a board that will switch your antenna input from one LNB to the other.

I do plane tracking via ADS-B on 1090mhz using a flightaware antenna from amazon.
I have some antennas for doing NOAA satellites but I haven't had a lot of luck with it.
I have a homemade yagi for fox hunting, but that's not really an SDR thing.
I have a 144.390mhz antenna for listening to amateur radio APRS messages and gating them to the internet.

nice picture dude. Cool antenna.
Yes, that's circular polarization. j-pole is a solid antenna, I recommend a 3 element yagi instead though. Plenty of DIY designs available online.

What are you talking about? You could easily point a dish at the moon

any advice for breaking into that line of work? do you work at nsa?

>icom

You mean the company that just issued a hit-piece about how open source digital radios are bad?
blog.icomamerica.com/2017/10/30/is-your-digital-repeater-ham-friendly/

their argument is about DMR as a protocol, it's not about "open source digital radios"

What the hell kind of antenna is that?

it's an array of stacked 2M yagi antennas for the sake of earth-moon-earth communication, moonbouncing.

I just decided to make my own antenna. What is the simplest antenna (and passive parts only, no lna or whatever) that would suprise me with results? I just want to see it working, so i don't really care about general usefulness, it could be super narrow and i'd build it for 250-260mhz range.

Yagi seems a bit too complicated, my only antenna-related achivement in my life was biquad for wifi. it worked better than small stick antenna that came in a box, so i guess it was a success. Is biquad for 250mhz possible? It would have to be enormous, and from fact that no one does it i deduce that it's just not very good idea.

theleggios.net/wb2hol/projects/rdf/tape_bm.htm
lna4all.blogspot.com/2017/02/diy-137-mhz-wx-sat-v-dipole-antenna.html

Can you lads name drop some decent radio manufacturers who sell stuff that won't drop me below the poverty line? I'm thinking of buying a basic discone that advertises 25MHz - 2000MHz as an entry into this hobby. I can't really justify spending $650 on a radio, though. You can probably tell that I don’t currently have any desire to transmit anything, since I don’t have a license.

BaoFeng

What's a good widest radio receiver?
I heard DEGEN DE-1103 was good a couple of years ago, but now it's not as good as it was.
What's the best readio receiver now?

Baofeng, Baofeng Tech, Yaesu. The PDF in has some suggested models you can look into.

Well, I feel better about my own hobbies after reading that

How do I start on sdr from zero?

Buy an RTL-SDR

Holy fuck you people are retarded.
It's legal to LISTEN to anything. You can listen to trunked radio legally. You can listen to the cops if they are broadcasting over the open air.

It's illegal to decrypt any encrypted communication. If the cops in your neighborhood have two brain cells to rub together all of the cool stuff is done on encrypted channels.

My advice, buy the RTL-SDR dongle from the rtl-sdr blog, get the super long telescopic antenna and go buy one of those clip on wind up shortwave antennas from Amazon. You should be able to direct sample and listen to frequencies as low as AM radio (the shortwave antenna really helps with this) and all the way up to ADSB traffic in my experience. If you want to listen to trunked radio, buy two, one for the control channel, one for the active voice channel.

You'll be able to listen in on 99% of nearby radio traffic for under $50. As a bonus you'll be able to listen to Alex Jones and people preaching Jesus on shortwave.

Infowars is on a shortwave station? Neat, I thought I was just going to pick up some church shit

buy a hamitup and 100ft of bare copper wire for a better experience

Thanks lads.

Yeah you're gonna be hearing a lot of convicted sex criminal Brother Stair and Infowars/libertarian crank style programming.

WBCQ has some regular weekend programs that offer music and such instead of preaching or news. Lumpy Gravy Party and the Zombo Mondo Record Party are two I remember. IIRC they've also got a program where you can buy an hour of airtime for $50 if you want to do an infrequent radio show.

I hope that baby gets raped

Oh there's also a lot of SW pirate activity around 6900 to 7000khz. Check the HFUnderground forums and the Hobby Broadcasting blog.
hfunderground.com/board/index.php/board,3.0.html
hobbybroadcasting.blogspot.com/

I want to get into sdr but I'm a neet. I did some astronomy-related research in college and it was cool.

We /contact/ now

>the iss
the iss is three orders of magnitude closer to earth than the moon.

I have no idea if you are right or wrong, just that it's not a good comparison.

Is LimeSDR better than HackRF?

If you ask how to start working on sdr, just do a msc in sdr, simple as that. Msc is important as it will lay the ground on sdr which is not avalable in almost all undrgrad courses.
How do jump in fpgas? Welp it was hard for me, i did a lot of work as an undergrad but now it is hard for me to find work on fpgas, that's why i am shooting at a phd.
No I don't work for the nsa, i am greek... I wanted to jump into our spy service when i was in the military, but they didn't let me in.
Sdrs are a very narrow field, though a huge part of your studies and work will be on networks so if you have a bad time getting a job as an sdr researcher, you can always apply as a very skillful network engineer.
If I was in tye states or the u.k. i would've gotten a job, i was offered a job in dublin but I declined.
It's a very very interesting tlfield.
My work on fpgas for optic fibre networks and wireless networks has been the most fun I had in my life.... It made your head overload but totally worth it.
I dunno if i ever manage to find a job on that topic, but i always have ky board and develop circuits for fan.

>but now it is hard for me to find work on fpgas
Just to clarify that. I have 3+ years of experience in fpgas, 1.5years working on sdr, 4 publications in total, i got 2 scholarships to work in the biggest research facility in Europe and the biggest one in greece...but life is hard even if you have experience.

...

nice dubs

who /adsb/ here?

...

Anyone listen to numbers stations or find any other cryptic broadcasts?

I kind of want to get in to this hobby but I have no idea what I'd do other than find a number station and then get bored after it's silent 99% of the time.

muh sex junk is so oh oh oh

>HackRF
should have waited for the LimeSDR

Man, you're dumb.
I've done it with a $25 SDR in my backyard. Made the antenna out of an old wok.

is that grafana hooking into dump1090?
that is awesome!

yes.
github.com/claws/dump1090-exporter
install prometheus
also the version of grafana in Raspbian is ancient, get a newer .deb from their website or unstable
grafana.com/dashboards/768

thanks for the links! do you upload to adsbexchange? If you don't, you should. They don't filter military aircraft and other interesting things like news/medical helicopters.

You should try to get that antenna higher. During the afternoon I get peaks up to 1800 messages / second

to be clear, I went a little overboard with my setup. I use very expensive low loss cable, filters and amps. The flightaware sticks and antennas are well worth the money.

tl;dr, you don't work in the field