RTL-SDR - an SDR receiver from a cheap DVB-T tuner on a USB connector

Gentlemen, I have a question, I have a RTL2832U + R820T tuner and I can not hear anything on the cb radio frequency. I will add that I have an external antenna, a straight dipole and I hear the police from about 10-20 km. On 430 I also hear repeaters from the area. And silence on cb? I'm using sdr sharp 13.

Have you set AM modulation?

What bandwidth do you have this dipole for? As for the range of ~ 2-3 m and you live outside the city, or there is no busy road nearby, you won't hear anything.

After 10 km outside the city

Will the antenna shown in the picture be better than a handmade dipole made of copper pipes? 150-170 MHz band. If so, please provide a better alternative.

To my eye it is an antenna for DVB-T UHF, i.e. above 470 MHz. Mounted on the picture will not let you listen to anything, because what we are interested in works in vertical polarization.

Buy Radmor 32812/1.

Hello, has anyone connected the tuner through an active laptop hub? Apparently it heats up less and does not interrupt the sound, and there is less distortion. A friend has a logilink and said so, but I would like to consult my colleagues here on the forum before I decide to buy such a hub.

Hi to all. I wonder if sdr can be used to accurately measure the frequency of quartz? to the frequency counter. Best regards.

szkieletor11111 wrote:

Hi to all. I wonder if sdr can be used to accurately measure the frequency of quartz? to the frequency counter. Best regards.

The other way around is to tune the rtl sdr with a quartz generator

Do you have the same as mine, i.e. on "xp" -ku sdrsharp program crashes?
Say, did the drivers upload the Zadig well?

Hello gentlemen,
my DSDplus shows in italics Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = BP

what do BP stand for in this case. Another thing is, I bought a Hytera 785G, programmed to a frequency where DMR is now a requirement (group + color + tx / rx) and the radio started listening in pre-programmed groups, but .... The base cannot be heard and some stations do. After some time, I did not see the ID of the transmitting radio on the screen, even though the DSD scanner was showing the transmission and decoding. The radio was deaf!
A moment ago on dsd again italics and Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = EP KeyID = 1 10s
Motorola and hytera do not understand each other too much on top of that, DSDplus decodes pretty much except one.
Games, I programmed my radio without encryption and started dsdplus, then 15 seconds I decoded DMR of my signal and then only stamps in dsd and again stamps and silence .... what is the reason for such behavior?

Hello, I have a question (RTL 820T2 - blue) what may be the reason that the tuner, after inserting it into the USB socket, heats up quite a bit after a short time, the LED starts blinking and disconnects every now and then (appears and disappears in the device menu and in Zadig- u) after taking it out - it works for a minute and the same starts again ... did it go a protection diode or what could have happened?

prezes_bct wrote:

Hello gentlemen,
my DSDplus shows in italics Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = BP

what do BP stand for in this case. Another thing is, I bought a Hytera 785G, programmed to a frequency where DMR is now a requirement (group + color + tx / rx) and the radio started listening in pre-programmed groups, but .... The base cannot be heard and some stations do. After some time, I did not see the ID of the transmitting radio on the screen, even though the DSD scanner was showing the transmission and decoding. The radio was deaf!
A moment ago on dsd again italics and Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = EP KeyID = 1 10s
Motorola and hytera do not understand each other too much on top of that, DSDplus decodes pretty much except one.
Games, I programmed my radio without encryption and started dsdplus, then 15 seconds I decoded DMR of my signal and then only stamps in dsd and again stamps and silence .... what is the reason for such behavior?

I think that if in your case the BP algorithm appears once and then on the same EP frequencies, you have coded EP, and BP appears because you have a weak signal (someone continues to transmit).

piterank wrote:

prezes_bct wrote:

Hello gentlemen,
my DSDplus shows in italics Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = BP

what do BP stand for in this case. Another thing is, I bought a Hytera 785G, programmed to a frequency where DMR is now a requirement (group + color + tx / rx) and the radio started listening in pre-programmed groups, but .... The base cannot be heard and some stations do. After some time, I did not see the ID of the transmitting radio on the screen, even though the DSD scanner was showing the transmission and decoding. The radio was deaf!
A moment ago on dsd again italics and Enc Group call; TG = XXXXXXX RID = XXXXX SLOT = 1 Alg = EP KeyID = 1 10s
Motorola and hytera do not understand each other too much on top of that, DSDplus decodes pretty much except one.
Games, I programmed my radio without encryption and started dsdplus, then 15 seconds I decoded DMR of my signal and then only stamps in dsd and again stamps and silence .... what is the reason for such behavior?

I think that if in your case the BP algorithm appears once and then on the same EP frequencies, you have coded EP, and BP appears because you have a weak signal (someone continues to transmit).

The transmitter signal is at the maximum level, maybe it's a matter of the coding itself in the programmed radio?

Record a sample from the discriminator, i.e. 48,000 Hz, 16-bit, mono, wave.

I'll take a look at what's going on, because that's how you can only guess.

I understand that you know the value of the key (please do not confuse it with the ID of the key, which is shown by DSD +) and on Motorola it can be heard, and on Hyter it does not want?

Hytera and Motorola get along on the Alleged RC4 40-bit extended key.

Proven in practice.

internick wrote:

Record a sample from the discriminator, i.e. 48,000 Hz, 16-bit, mono, wave.

I'll take a look at what's going on, because that's how you can only guess.

I understand that you know the value of the key (please do not confuse it with the ID of the key, which is shown by DSD +) and on Motorola it can be heard, and on Hyter it does not want?

Hytera and Motorola get along on the Alleged RC4 40-bit extended key.

Proven in practice.

Send me a prv number because I'm here occasionally. I can rip the samples. For me, sometimes the first 3 seconds are legible and understandable, and then just the packet flies and you can't hear anything.
I do not know the key yet, but I set the DMR radio to listen to the group, for example 9999999. My radio showed on the screen that there was a connection from, for example, ID 212121 but it was not audible, some of the IDs were heard, now the radio does not show or that it is the call neither hears nor sees the calls on the screen

sb8gapi wrote:

No wonder it cuts the sound as there is CPU load at 100%.
I suggest lowering the Sample Rate in Configure to 2048 MSPS or less even to 1024 MSPS.
Alternatively, download an older version of SDR Sharp from the forum:
https://www.elektroda.pl/rtvforum/download.php?id=565446 (version 1173)
or the Stable 1.0 version from the Aurora website
http://sdrsharp.com/downloads/sdr-stable.zip (has a lower CPU load than the latest version).
For HD SDR, you need ExtIO_RTL.dll (ExtIO_RTL2832.dll). One of them should be copied to the HDSDR folder.
The latest version of HD SDR and ExtIO_RTL.dll and ExtIO_RTL2832.dll from February 4, 2014 in the attachment.

Thank you so much for help.
Finally, rtl-sdr works for me.

Hi to all. has anyone can sdrsharp on 'xp'?

szkieletor11111 wrote:

Hi to all. has anyone can sdrsharp on 'xp'?

Hello, take a look at this topic, I threw away most of the necessary programs and described what and how to do it.
https://www.elektroda.pl/rtvforum/topic3182271.html

arkadi26 wrote:

sb8gapi wrote:

No wonder it cuts the sound as there is CPU load at 100%.
I suggest lowering the Sample Rate in Configure to 2048 MSPS or less even to 1024 MSPS.
Alternatively, download an older version of SDR Sharp from the forum:
https://www.elektroda.pl/rtvforum/download.php?id=565446 (version 1173)
or the Stable 1.0 version from the Aurora website
http://sdrsharp.com/downloads/sdr-stable.zip (has a lower CPU load than the latest version).
For HD SDR, you need ExtIO_RTL.dll (ExtIO_RTL2832.dll). One of them should be copied to the HDSDR folder.
The latest version of HD SDR and ExtIO_RTL.dll and ExtIO_RTL2832.dll from February 4, 2014 in the attachment.

Thank you so much for help.
Finally, rtl-sdr works for me.

Everything Ok, but I'm a happy owner of a radio with a discriminator

Here you have everything you need:

http://forums.radioreference.com/digital-voic...-software/191957-java-program-decode-dmr.html

https://github.com/IanWraith/DMRDecode

http://forums.radioreference.com/voice-contro...nnel-decoding-software/295152-dsd-status.html

https://www.dsdplus.com/download-2/

Make the voice settings on the older version as described here: http://www.scan-ne.net/DSD/DSD4WinTutorial.pdf

It shows the signal in%.

Here's some theory: https://www.youtube.com/watch?v=sPrSyfu_nvg

I have exactly the same, dsd java and dsdplus.

To correctly set the input level, please refer to the old DSD versions that show%. Correct decoding is a signal of 6-7%.

You can read about them here: http://forums.radioreference.com/voice-contro...ecoding-software/227386-dsd-windows-port.html

They are available for download, e.g. here: http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

Hello, in post 1027 I asked a question but none of my colleagues answered. So I took a risk and bought an active logilink ua0003 hub in an aluminum housing and I can say that there is actually less interference than when I connect the tuner directly to a computer or tablet. I greet everyone.

@don_viking And for the low bands; around the operating frequency of the power supply converter, this hub?

Unfortunately, I am currently in Germany and I do not have a tuner with the R820T2 chip, only FC0013 and I have no way to check. Before the new year, I should return to Poland and I will have the opportunity to test it. But in the band from 27 MHz up, there is a definite difference. There are no signals that are normally visible every 1 MHz.

Previously, in order not to have interference from the computer, I did this way that I put two SWA amplifiers on the antenna cable, one SWA at the antenna, and the other FP6L at least 4 meters from the tuner, so I could set the tuner gain to 7 and had the same station signal as with the gain full without amplifiers with interference from the tuner power supply from a computer or tablet. And the power supplies for the amplifiers, I tested two original transformer for a mesh antenna, additionally I did filtering and stabilization in it and the second GSV3000 and both have the same interference, which proves that they do not come from the power supply of the amplifiers if someone had such a theory.

I have a practical question, has anyone tried to use the tuner for measuring the analysis of the spectrum of the input signal (not received with the antenna)?
What is the sensitivity of a "bare" RTL circuit (will it catch a signal of -40dBm)?
What is the useful dynamic range of the spectrum measurement (for example, can you see -40dBm stripes against the -20dBm background)?

I am interested in measuring interference in devices in the band from ~ 0 to 200MHz, I read that it is possible to use the software measurement mode at low frequencies without the need to build a frequency conversion system, at the expense of measurement accuracy, of course, the question is how do these parameters deteriorate?

I would like to make a simple 150Mhz half-wave dipole and connect it directly to the popular "lv5dlx notonlyTV" USB receiver and here I have a few questions:
- Do I need an amplifier / power supply to catch some signal? Cable length 4-5m. The distance to the transmitter is about 16-17 km (I live in the countryside, the transmitter in the city).
- What cable to use? 50 or 75Ohm resistance? Which one will be better and why?
- What material for the antenna will be better? Copper or aluminum? Better tube / rod / does it matter?

@Szymon Tarnowski Sure, only to what extent will these results be reliable. The second issue is the software that will present these results in an accessible and useful way. The dispersion of the parameters of individual tuners is rather large, and their changes; as a function of time, they are also not negligible. You would also need to know the real parameters and limitations of the conversion systems used in these tuners as well as the RTL itself. So without proper calibration and setting of a given tuner, it will only be a toy or an indicator that something can work. As for the dynamic range, you can't expect much from a 7 bit adc, around 40dB.