RTL 2832u r820t

moonbounce · #1 (**permalink**) 02-25-2013, 8:50 AM

I just received my SDR from NooElec downloaded SDR Sharp and Zadig. I have the program running but all I get in noise. So at least I know that everything seems to be working I have the program set on the weather freq. of 162.475 but can't hear any voice. I have attached a better antenna. any help would be appreciated.

MikeOxlong · #2 (**permalink**) 02-25-2013, 9:44 AM

Did you select RTL-SDR/USB, select the proper Audio Output port and hit Play?

MikeOxlong · #3 (**permalink**) 02-25-2013, 9:46 AM

Don't forget to set your audio to nfm.

mtindor · #4 (**permalink**) 02-25-2013, 10:01 AM

And don't forget that, depending upon the application you are using, you'll need to either invert I/Q or not and will need to adjust frequency. It's very possible for you to take an out-of-the-box dongle, fire it up, and tune to 162.55 (as an example) expecting to hear something when in fact the dongle hasn't had the frequency adjustments done yet -- and so you don't find a signal where you expect one to be.

Look across a whole band until you find a signal, identify what the signal is and see what your frequency display is showing, and start correcting the frequency based upon that information.

Mike

mancow · #5 (**permalink**) 02-25-2013, 10:19 AM

You might have to increase the gain too.

rbm · #6 (**permalink**) 02-25-2013, 10:49 AM

Here are some settings that will get you started. (You may have to 'download' the image to see the details.)

Two possible problem areas.
Mine were pretty 'deaf' with the included antennas. You may have to set the gain very high and/or move the antenna around
One of mine had a cold solder joint at the antenna input connector.

Rich

By the way, in the image, you can see that I have the squelch turned on. Most times I have it turned off.

eorange · #7 (**permalink**) 02-25-2013, 12:27 PM

Quote:

Originally Posted by mtindor

...you'll need to either invert I/Q or not and will need to adjust frequency. It's very possible for you to take an out-of-the-box dongle, fire it up, and tune to 162.55 (as an example) expecting to hear something when in fact the dongle hasn't had the frequency adjustments done yet -- and so you don't find a signal where you expect one to be.

What do you mean, adjust frequency? I just obtained an RTLSDR late last week and have been playing with ADS-B via RTL1090, no problem, everything works great.

Just started using HDSDR (but not too much yet). I am wondering what the above means in prep for more playing around. Why would the RTLSDR be off frequency, if I'm understanding you properly?

rbm · #8 (**permalink**) 02-25-2013, 1:24 PM

Quote:

Originally Posted by eorange

What do you mean, adjust frequency?

I may be able to help with that question.
The oscillators in those dongles are not precision devices. Every one will vary from nominal by some amount.

If you look at the image I posted above, in the configuration window, you'll see a checkbox for 'OFFSET' and a setting for 'Frequency Correction ppm'.

Tune to something like a NOAA weather channel, click in the 'OFFSET' checkbox and the adjust the frequency offset to tune to the center of the selected signal.
Each dongle will be different. I have five of them and they range from 12-67 ppm.

Once set, (after a 40 minute warm up or so) it shouldn't change much.

Rich

offsite · #9 (**permalink**) 02-25-2013, 1:36 PM

moonbounce,

RTLs are easily overloaded. To see if this is the issue, start with RF gain at zero. Increase it gradually until the noise floor in the spectrum window starts to rise. Back the RF gain down one click from that point. This is the maximum RF gain setting you can use at that frequency. The max gain setting will vary from very low to almost full scale depending on which frequency band you are operating in.

While this may not be the issue, it's a frustrating one that we experienced here when we first started with RTLs.

Another (sounds unlikely) issue may be RTL frequency error. If you are expecting to see a signal at 162.4 MHz and are tuned there, the signal actually may appear at a different frequency. All RTLs need calibration. Some of them here are off by as much as 109 ppm. The best e4k here is off -84 ppm. The best r820t is off +91 ppm. This calibration setting also will vary a few ppm's depending on which frequency band you are operating in. And, you will notice a pretty big drift during warm up, too, or if you are operating outside and the temp is changing or the wind is gusting over the RTL and cooling it sporadically.

Hope some of this is helpful.

73
-rb-

Quote:

Originally Posted by moonbounce

I just received my SDR from NooElec downloaded SDR Sharp and Zadig. I have the program running but all I get in noise. So at least I know that everything seems to be working I have the program set on the weather freq. of 162.475 but can't hear any voice. I have attached a better antenna. any help would be appreciated.

eorange · #10 (**permalink**) 02-25-2013, 1:37 PM

Ah, I gotcha. Makes sense, and in fact I did see a little discrepancy with NOAA Wx on 162.55 in the little bit I played around. It wasn't registering with me what was going on.

(40 minutes?! Who has 40 minutes??

)

mancow · #11 (**permalink**) 02-25-2013, 2:01 PM

I just zoom way in on a noaa freq and adjust it for best centering.

moonbounce · #12 (**permalink**) 02-25-2013, 4:56 PM

Quote:

Originally Posted by MikeOxlong

Did you select RTL-SDR/USB, select the proper Audio Output port and hit Play?

Mike I have RTL-SDR/ TCP I don't have RTL-SDR/USB, which would bring me to another question. Are we all running the same version, I have version 1.0.0.1000?

moonbounce · #13 (**permalink**) 02-25-2013, 4:57 PM

Quote:

Originally Posted by MikeOxlong

Don't forget to set your audio to nfm.

Done.

moonbounce · #14 (**permalink**) 02-25-2013, 5:10 PM

Quote:

Originally Posted by rbm

Here are some settings that will get you started. (You may have to 'download' the image to see the details.)

Two possible problem areas.
Mine were pretty 'deaf' with the included antennas. You may have to set the gain very high and/or move the antenna around
One of mine had a cold solder joint at the antenna input connector.

Rich

By the way, in the image, you can see that I have the squelch turned on. Most times I have it turned off.

RBM, I have my SDR set up just like your with one exception, which might be my problem. As Mike state above I don't have the RLT-SDR/ USB I have RLT-SDR/ TCP?

As far as the antenna goes. I just removed the little antenna that came with the unit and screwed in a telescopice antenna, no difference,

Moonbounce

rbm · #15 (**permalink**) 02-25-2013, 5:22 PM

Quote:

Originally Posted by moonbounce

RBM, I have my SDR set up just like your with one exception, which might be my problem. As Mike state above I don't have the RLT-SDR/ USB I have RLT-SDR/ TCP?

As far as the antenna goes. I just removed the little antenna that came with the unit and screwed in a telescopice antenna, no difference,

Moonbounce

Yep, THAT's your problem!

You have to UNcomment the highlighted line in your 'SDRSharp.exe.Config' file.

It probably looks like this:


Make it look like the one in the image by deleting the first and last few characters to make it look like THIS:
<add key="RTL-SDR / USB" value="SDRSharp.RTLSDR.RtlSdrIO,SDRSharp.RTLSDR" />

(Or, you could just copy/paste the line above)

You 'should' see that option then.

Rich

By the way, the latest version of SDR# (1114) can be downloaded here.
http://sdrsharp.com/index.php/downloads

moonbounce · #16 (**permalink**) 02-25-2013, 6:00 PM

So I downloaded the latest version only to see the same thing as I have above?

rbm · #17 (**permalink**) 02-25-2013, 6:43 PM

Quote:

Originally Posted by moonbounce

So I downloaded the latest version only to see the same thing as I have above?

You MUST edit the config file to UN-COMMENT that line!
Otherwise SDR# will NOT play with your dongle.

If you have problems editing it, pm me and and I'll send you my config file to get you going.

Rich

Near the bottom of the file, you'll see this:
Notice that the line that contains 'RTL-SDR / USB' is commented out.
You will not see it as a selection until you uncomment it.

<frontendPlugins>
<add key="SoftRock / Si570" value="SDRSharp.SoftRock.SoftRockIO,SDRSharp.SoftR ock" />
<add key="FUNcube Dongle Pro" value="SDRSharp.FUNcube.FunCubeIO,SDRSharp.FUNcube " />
<add key="FUNcube Dongle Pro+" value="SDRSharp.FUNcubeProPlus.FunCubeProPlusIO,SD RSharp.FUNcubeProPlus" />

<add key="RTL-SDR / TCP" value="SDRSharp.RTLTCP.RtlTcpIO,SDRSharp.RTLTCP" />
<add key="SDR-IQ" value="SDRSharp.SDRIQ.SdrIqIO,SDRSharp.SDRIQ" />
</frontendPlugins>
<sharpPlugins>
<add key="Wave Recorder" value="SDRSharp.WavRecorder.WavRecorderPlugin,SDRS harp.WavRecorder" />
<add key="Frequency Manager" value="SDRSharp.FrequencyManager.FrequencyManagerP lugin,SDRSharp.FrequencyManager" />
</sharpPlugins>
</configuration>

moonbounce · #18 (**permalink**) 03-05-2013, 8:58 PM

So I have had my rtl 2832u r820t that I bought from Nooelec up and running, and I must say if you don't have one get one for 25 bucks you can't go wrong. I have had mine running for 2 days and I must say I am impressed with this little dongle, it does everything my regular scanner will do. I have received everything from 26 Mhz up to 800 mhz including the am 118 to 136 band, WFM and AM. What I like about this dongle is that you can see a whole lot of band, and you can see if it is active or not. with a scanner you have to scan through all bands, with the dongle you can see the whole band and you can click on spikes in that band to listen to it. I must say that the SDRSharp program is top notch even though I is difficult to install, for me anyways.

I must say that if it wasn't for poster "rbm" my dongle would be in a drawer, I had given up trying to install SDRSharp, thrown my dongle in a drawer thinking I would never see it again, I had totally given up getting the program installed even with rbm's help. For me it was drawer bound end of story but rbm kept PMing me and made it more simple for me and I kept trying and now it is up and running and I am having a blast with this thing. So in return for rbm's help, if I can be of any assistance to anyone with the dongle or SDRSharp just PM me and I will do what ever I can to help you.

p.s. Thanks rbm without your help this dongle would never have seen the light of day..

Moonbounce

Moonbounce.

kd7eir · #19 (**permalink**) 03-05-2013, 9:33 PM

I should have my RTL 2832u r820t on Friday. Based on what I have been reading this should be a great addition to amateur radio hobby. It's great to know that there are people here that are willing to help should I need it. Hopefully I will not need any help, as I tend to read everything that I can find while waiting for my new toys to arrive at the door.

searingxheretic · #20 (**permalink**) 03-05-2013, 9:35 PM

Quote:

Originally Posted by kd7eir

I should have my RTL 2832u r820t on Friday. Based on what I have been reading this should be a great addition to amateur radio hobby. It's great to know that there are people here that are willing to help should I need it. Hopefully I will not need any help, as I tend to read everything that I can find while waiting for my new toys to arrive at the door.

It is taking a bit longer than I'd hoped, but I should have mine in a day or two, according to USPS. I'm like a kid at Christmas, I can't wait!

Sent from my cm_tenderloin