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Help receiving ~437 MHz Cubesat Signals

Hi everyone. I'm working on a school project which involves receiving cubesat signals in the 437 MHz range. I've successfully done this before in the ~137 MHz range but unfortunately I'm struggling a lot with this. Can anyone point me in the direction of a helpful guide? We need something that is omnidirectional.

Yesterday we tried to make a QFH antenna but after testing multiple passes we were not able to receive anything. I'm not quite sure if we made it correctly. We were using this calculator to make it, but used the same diameter for both loops as we wrapped the wire around a 4 inch 2 liter bottle. Has anyone used this website before?

submitted by /u/siyman4
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troubleshooting interference

I have a signal that stays even when I change Frequencies. and unsure what might be causing it. I'm in the plans on buying Ferrite beads, and an Active USB cable because I almost live in a natural Faraday cage in my bedroom. (apartment so best I can do is move Antenna)

few photos.


submitted by /u/deanec64
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Car keeps getting unlocked by a device thieves using

The car is not a keyless entry system, i have tried doing a replay attack to see if my car has a code that does not change and have not been successful using a raspberry pi and rpitx. Any idea how these theives are breaking into my car is it possible the car is a rolling code and they are just bruteforcing the key fobs next code?

submitted by /u/jsteg176
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Newbie here. Trying to get my RTL2836BU based TV tuner to work as an USB SDR.

Hello everyone, newbie here. I've recently picked up a RTL2836BU based TV tuner (Magic Pro ProHDTV mini 2) for free, and wanted to use it as an SDR, but when I press play in SDR# it says "no device found". I've tried reinstalling drivers with zadig, used USB Driver tool, tried different USB ports (2.0 and 3.0) and tried different software with no luck. Any help?

submitted by /u/OPGuyK
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How do I determine rtl_fm parameters?

I'm using rtl_fm from the command line to listen to the police scanner and emergency services in my area, and I'm using to help me set it up, but it led to some questions.

For police scanners, it recommends a setting like:
rtl_fm -M fm -f 154.42M -f 154.75M -f 154.82M -f 154.89M -s 12k -g 50 -l 70

What's the purpose of specifying multiple frequencies? Does it just cycle through the different frequencies, so it might play 5 seconds of one, then 5 seconds of the next, and so forth? Or does it pick up and play all those frequencies on top of each other like if I was playing multiple stereos at the same time? Or maybe it monitors the different frequencies and then just plays whichever has the strongest signal at any given moment?

As far as the g parameter, it says to set the gain to the maximum by using a value appropriate to your dongle. I'm using this dongle. Do I look up the dongle specifications to see what the maximum gain is and use that value? Or is this a number I just play around with? (Which I have been without much success.)

And then with the l parameter, it says this squelch values varies a lot, based on what gain and sample rate I use. Is this another playing around with number, or is there some kind of calculator I can use?

Right now I pick up commercial radio just fine, but when listening to the police station I hear mostly static. I can here the station just fine using an desktop police scanner, so I don't think I'm having any issues with P25 or trunking. If they're talking, the static stops and you can here very faint voices but cant make out any of the words. It seems my hardware is fine and its just a matter of figuring out these software settings.

submitted by /u/Oscar_Mild
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Newby question: need help listening to a frequency from the command line

I'm using a raspberry pi from the command line and I'm using this usb radio dongle. I also set it up using the Linux section of this quick start guide.

Right now all I'm trying to do is to listen to a radio frequency from the command line. I've been using man pages and reading other posts, but the best I can do is listen to different frequencies of static.

For testing purposes, I'm trying to listen to a local radio station broadcasting on 88.1FM.

Right now my syntax is:
rtl_fm -f 88.1M | aplay -t raw

It's just static. What am I doing wrong?

submitted by /u/Oscar_Mild
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Military Air-band. What language is this?

Hey guys,

I was scrolling a bit through the military air band on SDR# and came across a couple of more or less strong signals.

I went to record a little bit because according the intonation has some portuguese, but I can't understand anything of it and a little portuguese I should be able to understand.... but then receiving portuguese military air in the Netherlands seems a bit awkward. Can anyone tell which country's military air I've been listening to?

MP3 here:!P1tHDAIR!IGi6Cmj1hpgADWa4W_2mFwCNetNdnLvUN8HapG7JCTg

and another MP3:!P1tHDAIR!IGi6Cmj1hpgADWa4W_2mFwCNetNdnLvUN8HapG7JCTg

submitted by /u/theakito
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Looking for assistance

I'm brand new to SDRs as a whole. I've been working with dedicated receiver systems for the past few years for work, but work is wanting to look at adding SDRs.

Ultimately we are looking to record anywhere from 1MHz to 100MHz at a 40MHz bandwidth. I've found that the LimeSDR is capable of getting up to 60MHz bandwidth. I'm having an issue finding resources for making an antenna that is capable of the frequency range I listed. Most ones I see are from 1MHz to 30MHz.

Would anyone here be able to provide assistance.

submitted by /u/sgtdumbass
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Plugged my sdr into my Android car radio and received ADS-B while sitting in traffic

Plugged my sdr into my Android car radio and received ADS-B while sitting in traffic submitted by /u/Bobcalamarie
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QFH Connections

QFH Connections submitted by /u/njrusty
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