>have shortwave radio >hear of SDR >buy standard DVB-T Dongle with suitable chipset >wanting to receive EVERYTHING >first week listen to FM radio stations, record multiple with gqrx >second week listen to 446 MHz PMR transmissions >third week listen to APRS -- record text
until now everything was fine
>fourth week >want to listen to NOAA weather sattelites >read articles about weather fax, apt ... >install hamfax (fax software) (works) >install gpredict (sattellite tracing software) (works) >read article about s.o. who received NOAA-15 signals with rtl_sdr device ( dk3wn.info/sat/wetter/sat_noaa18.shtml ) >wait for NOAA-15 >wait for signal in gqrx >nothing >check antenna -- is ok >check cable -- is ok >chekc other (local) signals -- can receive them
WHAT THE FUCK! WHY CAN'T I RECEIVE THE SATTELITE Why can this other guy do it? >tfw i can't into receiving weather sattelites
(pic related isn't tuned to the right frequency, but the freq. at which NOAA-15 transmits (137.5 MHz) should be visible!!!)
>buy standard issue dvb-t dong >not expecting every standardized chipset to be backdoored and refuse to listen to any sensitive signals
lel you have some reading up to do.
Alexander Barnes
hack rf one?
Gavin Taylor
>sensitive signals >weather sattelites ...
also: >other person using rtl_sdr hardware >showing pictures! what is wrong?
Jaxson Cooper
>some reading what do you suggest
Ethan Fisher
Do you have a right hand circularly polarized antenna tuned to 137 MHz? WXtoImg for decoding the APT signal?
Benjamin Jackson
one of these?
Carson Cruz
You capturing at the right time? Ever try Orbitron?
Brandon Cruz
What antenna are you using? i made this with some coax wires, pcb drainage tubes and tape. The noaa signal is very weak, try getting to higher ground
Carson Young
i got this with a chinese 5 dollar dongle and my shitty homemade duadrifilar helix antenna when i tried it a year or two ago
Juan Morales
>rained today
Thanks, but one year too late.
Benjamin Morales
stop being autistic and just get your weather form the internet you stupid nerd fuck
Chase Roberts
can you listen other devices with it? like car remote key or IR gate?
Camden Scott
im a newfag to this shit, what the fuck is all of this? and what is it used for?
Easton Wood
Yes, i can receive almost all of my neighbours' outdoor temperature and humidity sensors with a program called "rtl_433". I'm going to buy/build myself some different antennas (for different bands). That should do it.
Parker Martinez
>Hardware AGC on >LNA gain at max
Nice overdrive. Try HW AGC off and LNA gain around 10dB.
Evan Murphy
Also with high probability your antenna is not usable with that wide scale of frequencies. If you have space available I'd recommend some discone antenna for SDR stuff. Something like Diamond D3000N.
I'm snooping on police/ ambulance pacer transmissions. I'm going to start listening on satellites soon, i think.
Jeremiah Jackson
Satellite signals are vastly weaker than most anything terrestrial aka on the ground that you're going to receive. Shit, your cell phone is radiating more powerful signals at any given moment than the strength of the signal from a satellite is by the time it gets through the atmosphere and to your antenna whatever or wherever that might be.
If you do some research you'll find that people either buy or construct helical antennas like the one pictured for receiving satellite signals with a bit more *uNF* to them. You can use LNAs (low noise amplifiers) as well with traditional antennas to help but, a helical tuned directional gain antenna is precisely what you need to get the best possible signal reception from anything in orbit.
They're easy to construct from bare electrical wire, not that hard at all, but getting the coil shaped properly is the tough part. There are plenty of guides out there for that however.
Thomas Hall
Is it going to be expensive to buy stuff to start with with SDR?
James Bell
>see that image >the waterfall >all yellow and red and nothing useful visualized
My god man, back the fuck off the slider on that, you should be looking at something like this for actually useful visual information.
Reduce the middle slider on the right (Contrast) till you see pure black in the background (which would normally be the noise you DON'T want to visualize) so that any actual signals stand out from the noise.
See how that works? With what you have now you're not getting much of anything useful but a fucking wall of "fire" basically. Adjust the contrast and the signals will jump right the fuck out and be easy not only to see but to identify just from what they appear as on the waterfall.
>I swear to god the image CAPTCHA I just got was WATERFALLS >Google is spying on my god damned keystrokes >AARRRGGGHHHH
Bentley Gonzalez
I'm in Europe: Frequency is 144.8 Mhz
Mason Diaz
Ah, thanks. Much better.
Aiden Ortiz
>fucking wall of "fire" keked! and true!
Xavier Nelson
Confirmed for not knowing shit about RF.
Isaac Martin
It's one of those things that people new to SDR applications tend to misuse the most, they'll have waterfalls that look pretty much like that and you can't realistically pick out much of anything useful from the visual info. Adjusting it so the noise fades into the background (literally) allows the actual signals to appear and stand out which is the entire purpose of the waterfall. After awhile you can tell exactly what type of transmission format it is just by the signal's visual representation.
Here's a site that offers a shitload of visualizations to get people started:
And here's two sites to help ID signals just from what they sound like, especially the digital formats if you don't decode them with something like DSD+: