Архив за 08.02.2020

New to SDR not getting anything but FM

I have setup my rtl-sdr dongle (an official one from the blog website) and its hooked up to a raspberry pi in my loft using the diapole that comes with the kit but i'm getting nothing but FM radio. Not a thing.

FM comes through loud and clear, and I experimented with the gain option in rtl_tcp but yeah, still nothing.

I can see what I think are tone generators / beacons or something that just broadcast a constant tone at some frequencies , but I wonder why i'm not picking up anything else at all. There's a large marina near me, i'm close to a town centre, the local busses I know for sure use PMRs.

Any suggestions please? Do I need a better antenna ? I'm sure i should be able to pick up at least something besides FM using the supplied one.

submitted by /u/fungyfungy
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Problems receiving Meteor M N-2

Hello all,

I successfully got two images from NOAA satellites and it was probably by chance because I use some settings found on a tutorial mixed with others and I ended up getting "not so bad" images.

Now I'm trying to get Meteor M N2 images. This morning I made an attempt and I saw a really weak signal on the waterfall.

My settings were those ones :

-------------

GQRX :

Input rate : 2560000

Decimation : 32

Sample rate : 80.000ksps

Bandwith : 0

LNB LO : 0

Audio output : Sample rate 48kHz

Input Control : default (all unchecked)

Receiver Options :

Filter width : Normal

Filter shape : Normal

Mode : Raw I/Q

AGC : Off

FFT Settings : Is it useful ?

-------------

  • I have no idea of how I should configure my device (Input rate, Decimation, etc..) is there a way to find the information of how to configure it depending on the signal you're trying to receive ("empirically" or "scientifically") ?
  • How do I change the bandwith and what's the value I should set it ?
  • I found that gpredict can track the satellite to change the frequency with the dopler effect, do I need to use it ?
  • Is there someone that can successfully record a Meteor message using gqrx that can send a screenshot of his different settings ?
submitted by /u/tenupFr
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Troubleshooting Help • Re: Multiple RTL-SDRs Question

I've made progress on this and want to share what I did so others who have similar issues may find a way forward.

First of all, as a correction to the above, you don't actually need 2 radios to use unitrunker 2.x, but it may be advised.

More to the point, I ended up contacting Joanne directly. She was extremely helpful in helping to isolate a big part of the problem. Essentially, no matter what changes I was making to the devices by uninstalling, reinstalling, etc, the registry entries were holding me back. Once I deleted the registry entries and then went through the process again, it was easier to discover that my best solution was to use eeprom to reset each device to their default settings, and then move on from there.

However, while this knocked some of the 'ghost' dongles off, it still remained that when I loaded unitrunker 2.x, multiple dongles were displayed beyond what I actually had plugged in, and Windows Device manager showed 2 devices for each one plugged in.

I found my solution hinted in this thread here:

https://forums.radioreference.com/threa ... rt.400469/

"You have a phantom third RTL device because you probably installed the driver with zadig to the bulk-in interface. You want to actually install the driver to the RTL2838UHIDIR (Composite Parent) device."

Combined with something said in the Unitrunker 2x group that explained that these devices, from the POV of the computer, have two separate USB components; thus the advice to install the drivers to bulk interface 0, and not bulk interface 1. However, using the radioreference tip, I enabled zadig to show composite devices and I saw that my RTL2838UHIDIR devices were showing default generic USB drivers, and not WinUSB ones. I installed WinUSB to each of the RTL2838UHIDIR devices (plugged in, one at a time), and all of the ghost dongles completely disappeared, leaving just the three distinct RTL2838UHIDIR devices.

Not sure where the problems started, exactly. I was trying to change the serial numbers of the devices but I think I was trying to write to one or more of the 'ghost' dongles, got confused, or at anyrate, got to the point where the devices wouldn't respond correctly and consistently anywhere.

I don't know if there are downsides to installing the drivers to the composite (RTL2838UHIDIR) rather than bulk interface 0, but so far in the places where I am concerned (SDR# and Unitrunker 2x), the radios appear to all be working as designed.

Thanks all for help. And good luck.

SB

Statistics: Posted by snowbranch — Sat Feb 08, 2020 9:04 pm


Antennas • Re: Question regarding loop designs

Any of your options as far away from the metal grid as possible would be best.

Statistics: Posted by hotpaw2 — Sat Feb 08, 2020 5:57 pm


How to catch a mouse with a 137MHz Double Cross?

Securing Antenne's on the Garage roof for upcoming storm Ciara i did discover my Double Cross 137MHz has a new fetish hobby catching mouse animals..

https://imgur.com/a/ZxwM7Ey

submitted by /u/happysat77
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Комментарий к записи RTL-SDR: первое включение (JKTU)

у меня всеравно выдает ошибку — неявляется приложением WIN32

Binary from ASK (What are 1 and 0)?

This is my first post ever so if I am completely out of order, let me know.

Following this project on using really cheap 433Mhz reciever to get the digital signal from RF-devices via a 3.5mm audio plug and Audacity, I have embarked on what seems to be a very fun but difficult journey. I have very limited knowledge on both radio and electronics but a persistent will.

I've gotten to the point where I have some clear "on's" and "off's" and think I have determined the timing of them:

https://imgur.com/a/sUn9THK

On = 27 sample points / 48000Hz ≈ 563 µs

Short off = 32 sample points / 48000Hz ≈ 666 µs

Long off = 62 sample points / 48000Hz ≈ 1292 µs

Comparing with the result shown in the project I have followed and others doing similar things, my wave does not really match any of them and I'm having a lot of trouble figuring out what are the 1's and 0's in this.

All of my "on's" are the same lenght and my "off's" are either 32 or 62 sample points long. I have tried my best to read up on the topic but I feel like I am missing some crucial piece of information to figure this out.

I hope that I might be in the right sub for this and have supplied enough information and if not I would appreciate if someone could point me in the right direction.

submitted by /u/Skapells
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Antennas • Re: Question regarding loop designs

It will be around a vertical square metal grid which is about 1x1 meter (3x3 feet) in size (So 1 square-meter (9 square-feet))
Just what do you mean exactly about a metal grid? Having any metal close to an antenna is not a good idea, as it is very lossy. A few more details on what and why of the metal grid would be helpful.

73, Bruce, VE3EAR

Statistics: Posted by VE3EAR — Sat Feb 08, 2020 2:44 pm


KerberosSDR • Re: KerberosSDR App and bearing server

Hello

I bought RDF Mapper and I can't see my mobile station
on the map.
Kerberos SDR on my smartphone does not communicate with the RDF Mapper server
I give it the server address, the name of my station, and upload to Rdf Mapper on.
But nothing is happening.
On RDF Mapper I give it the same address of the server, the same name of my station.
He tells me Dowload OK. (RDF Mapper communicates with the server)
At the bottom of the screen he tells me
"Station not found on server".
The problem would come from the software on the smartphone which does not communicate with the RDFMapper server?
My smartphone is good for connection sharing.
I do not understand.
Ideas?

Thank you

Statistics: Posted by PERILLOS — Sat Feb 08, 2020 2:18 pm


Russian Satcom pirates talking English — 255.560Mhz

Russian Satcom pirates talking English - 255.560Mhz submitted by /u/plummet555
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