SDR Questions

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RonnieUSA

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This is the Dongle I'm trying to use. ( Amazon.com : Vantech RTL2832U R820T DVB-T SDR DAB FM USB DIGITAL TV Tuner Receiver RTL-SDR Project + DAB dongle Tuner For Laptop PC : Audio Component Tuners : Electronics )

Followed this guide ( Quick Start Guide - rtl-sdr.com )
I can get FM to work, and can listen to the Weather Frequency 162.425 where I live.
The problem is when I try to listen to 453.975 an analog frequency in NFM I got no sound, just what sounds like a roaring noise.
What am I doing wrong?
I have all of the plugins installed.
I thought I would start with analog, and then move forward from there, if I can get it working.

Thank You for any help on this.
 

KC1UA

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What is 453.975 and are you sure it's an analog signal? A considerable number of business type communication systems have been changed from analog to digital, either DMR or NXDN. If what you're hearing sounds somewhat like a control channel that may well be the case. Considering that you're hearing NOAA Weather I'd say you have a working system.
 

RonnieUSA

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What is 453.975 and are you sure it's an analog signal? A considerable number of business type communication systems have been changed from analog to digital, either DMR or NXDN. If what you're hearing sounds somewhat like a control channel that may well be the case. Considering that you're hearing NOAA Weather I'd say you have a working system.
Fire & EMS Dispatch where I live, FM Radio sounds darn good.
Here is a screen shot.
 
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KC1UA

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Well your screenshot is still showing that you're using WFM. FWIW I'd also uncheck FM Stereo. Other than that if your target is an analog NFM signal and you're hearing NOAA weather in NFM, I don't know what the issue would be. Outside chance that your PPM adjustment may be varying between VHF and UHF bands, but from my experience that won't create a roaring sound, but instead choppy distorted audio.
 

rbm

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If you're trying to use the tiny antenna that comes with those dongles, you won't hear much at all.
And you'll need to hit the 'Configure' button and set the RF gain somewhere in the center to start.
The default is for it to be set to zero.

For NOAA broadcasts, you should be using NFM not WFM.
Your filter bandwidth is much too wide.

I use NFM and 12,500 bandwidth to cut out adjacent channel interference.
The 'official' recommendation is:
"The NWS recommends the public purchase receivers with a 0.5 to 1.0 microvolt sensitivity for 20 decibels (dB) quieting, a selectivity of 45 to 70 dB down at +/- 25 kilohertz (kHz)"
NOAA All Hazards Weather Radio

Rich

Here's a screen capture of the settings I use for NOAA broadcasts.
 

RonnieUSA

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If you're trying to use the tiny antenna that comes with those dongles, you won't hear much at all.
And you'll need to hit the 'Configure' button and set the RF gain somewhere in the center to start.
The default is for it to be set to zero.

For NOAA broadcasts, you should be using NFM not WFM.
Your filter bandwidth is much too wide.

I use NFM and 12,500 bandwidth to cut out adjacent channel interference.
The 'official' recommendation is:
"The NWS recommends the public purchase receivers with a 0.5 to 1.0 microvolt sensitivity for 20 decibels (dB) quieting, a selectivity of 45 to 70 dB down at +/- 25 kilohertz (kHz)"
NOAA All Hazards Weather Radio

Rich

Here's a screen capture of the settings I use for NOAA broadcasts.
Thank You for the screen shot, and settings, it sure has seemed to have fixed the problems, and the weather is working great using NFM.
Again Thank You.

Now to play some more.
 

RonnieUSA

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Now that I have the analog part now working, I have used DSDPlus with a scanner, but now I need to set it up for this dongle.
I'm not hearing anything.
Here is a screen shot of my DSD settings.

Thank You for all of the help so far, and any more that I get.
 
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rbm

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RonnieUSA

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Since you're interested in digital modes, you'll want to 'calibrate' your dongle 'Frequency Correction (ppm)'.
Just a few ppm off and it will mess up any digital decoding.

Here's a link to an earlier post of mine describing one way to do the calibration.
There are other ways but this is quick, easy, and reasonably accurate.

http://forums.radioreference.com/software-defined-radio/278821-need-help-sdr-nooelec-r820t-sdr-dvb-t.html#post2078993

Rich
Thank You, I'll do that.
 

br0adband

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SDR# + the (Frequency Manager + Scanner plugin) = about the best that we can do given the still relatively "new" state of RTL stick software development at this point in time. Haven't tried the Easy Scanner plugin so I can't offer any help with that one, but the Frequency Manager + Scanner plugin available from the author's website is what I use myself and it works great in that respect - you add frequencies to the database (comes with a great import/export/conversion utility as well), create a group or groups, add frequencies to that group or groups, and then you can scan single groups at a time (or get multiple ones that are all included in one big group, I suppose, like having a top level system with secondary ones below it, etc).

It works, that's all I can say. ;)
 

RonnieUSA

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SDR# + the (Frequency Manager + Scanner plugin) = about the best that we can do given the still relatively "new" state of RTL stick software development at this point in time. Haven't tried the Easy Scanner plugin so I can't offer any help with that one, but the Frequency Manager + Scanner plugin available from the author's website is what I use myself and it works great in that respect - you add frequencies to the database (comes with a great import/export/conversion utility as well), create a group or groups, add frequencies to that group or groups, and then you can scan single groups at a time (or get multiple ones that are all included in one big group, I suppose, like having a top level system with secondary ones below it, etc).

It works, that's all I can say. ;)
I got the Easy Scanner to work after rebooting the computer.
Don't understand why it wouldn't work till I did that, but it's now scanning the frequencies I want to hear that can't be scan by a scanner.

Thank You for your reply, I'm just getting into this, and it's been a job to get it to work.
I'm scanning several NXDN Systems.

Thank You to everyone who has helped me on this.
 

RonnieUSA

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Removed the Easy Scanner Plugin, wouldn't stop on anything while scanning.
Got the Frequency Manager + Scanner plugin to work, but the scan, and hold settings don't seem to be working right. I may have messed them up.
 
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RonnieUSA

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Got everything fixed.
I deleted the SDR# folder, and started over, and everything is working fine, both analog (when I want to play), and digital, the main reason I got this.
Main use is for NXDN, and DMR.

The computer I'm using is a Gateway E4300 with an Intel® Pentium® 4 520 Processor with HT Technology (2.8 GHz, 800 MHz FSB, 1 MB cache, Socket T), with 1GB of Ram running Windows XP Pro x86.
 

br0adband

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When I first started with this SDR kick just about 2 months ago, the first few hours were incredibly frustrating because not everything worked as expected. I followed (mostly) the two or three most frequently mentioned guides to getting the RTL sticks working with Unitrunker and SDR# to monitor trunking systems - didn't even care about the digital aspect at that point and DSD was the only option - and just had zero luck with it. Gave up on it, got pissed at not being able to get it functional, then started again a second time doing it the way I expected things should work based on the hardware and the software and was successful that second time around (sometimes it takes a third charm 'cause that's the charm, of course).

Then a few weeks later DSD+ appeared and that's when I really got serious about this monitoring, especially with DMR/MOTOTRBO traffic. I do put the effort into NXDN but it's barely used here (3 systems noted, maybe a 4th in progress) whereas DMR/MOTOTRBO is used quite a bit more, and then there's P25 which I still only have one system worth monitoring which is Nellis AFB but even that's a chore based on the current state of things with SDR and the need to use multiple apps to get it all done (yes I know I reiterate this often, my apologies).

And now it's like second nature, of course, but new stuff is always tough for most anyone to get into, especially this new way of doing things but it becomes fairly entrenched fast.

It's all trial and error, repeat ad nauseum till it works. ;)

Congrats on getting it all working as you'd hoped...
 
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