Topic: NOAA WEATHER RADIO

[tim273]

I believe the NOAA AM bandwidth is 5 kHz...especially on the older transmitters... a sampling rate of 16 kHz would be expected to handle up to 8 kHz without aliasing -- however, aliasing could also be introduced with higher volume input levels, and noise within the source, so an even higher sampling rate could produce a "cleaner" sound, to the ears, than the lower sampling rate...especially if you have a 'dirty' or poor signal in, in many cases, believe it or not...
 I use 24 to 56 K

Exactly, when I first did the WU stream, I started with the recommended 16 bit rate and it sounded like it was coming out of a tin can and very digital sounding, so I upped it 24, better, then 32, better yet and then finally settled on 64 with 48k sampling and it sounded more like you were listening to it from the weather radio itself.

[Cutty Sark Sailor]

'Bout to fade away... no interest?

[tim273]

I suppose it's about getting the word out, not many know about this.  Also, if Weather Underground is actually "working on it", that suggests they will have their server back up at some point and everyone would go back to streaming to them.  Time will tell I guess.

[satcop]

Agreed, the vast majority of the WU suppliers for instance, I am sure are not aware of this option, probably are not on this forum.  Although I doubt we have everyone yet who has a stream and is on this forum.  How to get out the word?  Note should also have an invite on the page itself.

I have found the side discussion on the SDR method to be quite useful to the point where I am in the process of putting one together with a raspberry pi myself and see if I can't bring in another feed.

Bob

[satcop]

Well I just got the following email from "William" at WU:

We have an official announcement on the 1st, but I can confirm that we're ending the radio feature.


Thank you,
William
Wunderground Support

So if you were feeding WU and were waiting for it to come back, don't hold your breath.   

Bob

[vreihen]

Ok, so I switched to using an RTL SDR instead of a regular radio for the MSP one.  It's about the same, but now I don't need the radio or sound card and it's on a Raspberry Pi 3 and I'm using this: http://www.nooelec.com/store/sdr/sdr-receivers/nesdr-mini-2-plus.html and I purchased a kit that includes an SMA adapter which have connected to an antenna in my attic.  Here's what I used for the command line, I started it in screen so that I can detach from it:

rtl_fm -f 162.55M -s 48000 -l 0 | lame -s 48000 --lowpass 3200 --abr 64 --scale 9 -r -m m - - | ezstream -c /etc/ezstream.xml

Tim - Can you elaborate on what was needed to set this up?  In particular, what is listening on port 8000?  I'm trying to replicate your work, hoping to build a script to automate the installation so anyone can easily set up a NWS stream.....

[tim273]

Ok, so I switched to using an RTL SDR instead of a regular radio for the MSP one.  It's about the same, but now I don't need the radio or sound card and it's on a Raspberry Pi 3 and I'm using this: http://www.nooelec.com/store/sdr/sdr-receivers/nesdr-mini-2-plus.html and I purchased a kit that includes an SMA adapter which have connected to an antenna in my attic.  Here's what I used for the command line, I started it in screen so that I can detach from it:

rtl_fm -f 162.55M -s 48000 -l 0 | lame -s 48000 --lowpass 3200 --abr 64 --scale 9 -r -m m - - | ezstream -c /etc/ezstream.xml

Tim - Can you elaborate on what was needed to set this up?  In particular, what is listening on port 8000?  I'm trying to replicate your work, hoping to build a script to automate the installation so anyone can easily set up a NWS stream.....

Sure, so I started with a Raspberry Pi and installed the following (after updating of course):

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sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install screen, vim, htop, icecast2, lame, libmp3lame-dev, ezstream, rtl-sdr

Once all that is done, set up Icecast (it uses port 8000, but that can be changed):

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sudo vim /etc/icecast2/icecast.xml

Find the authentication section and change the passwords and then restart the server:

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sudo service icecast2 restart

Then you can browse to http://ip-of-raspberry-pi:8000 to see the Icecast server, there won't be any streams yet.  Next set up ezstream which will stream to Icecast.  Create an ezstream.xml file somewhere on your filesystem, and then there's example xml files here: https://www.apt-browse.org/browse/debian/wheezy/main/i386/ezstream/0.5.6~dfsg-1/file/usr/share/doc/ezstream/examples, I used this one as my base: https://www.apt-browse.org/browse/debian/wheezy/main/i386/ezstream/0.5.6~dfsg-1/file/usr/share/doc/ezstream/examples/ezstream_mp3.xml

Change the sourcepassword element to the password you set in icecast.xml and change filename to stdin, update the url and change /stream to what you want your stream to be mounted to, also update the svrinfo elements:

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<ezstream>
    <url>http://localhost:8000/tim273/edina</url>
    <sourcepassword>your_password</sourcepassword>
    <format>MP3</format>
    <filename>stdin</filename>
    <stream_once>1</stream_once>
    <!--
      The following settings are used to describe your stream to the server.
      It's up to you to make sure that the bitrate/samplerate/channels
      information matches up with your input stream files. Note that
      <svrinfoquality /> only applies to Ogg Vorbis streams.
     -->
    <svrinfoname>Minneapolis, Minnesota Weather Radio</svrinfoname>
    <svrinfourl>http://www.wunderground.com</svrinfourl>
    <svrinfogenre>Weather</svrinfogenre>
    <svrinfodescription>NOAA Weather Radio KEC65 162.55Mhz</svrinfodescription>
    <svrinfobitrate>64</svrinfobitrate>
    <svrinfochannels>2</svrinfochannels>
    <svrinfosamplerate>48000</svrinfosamplerate>
    <!--
      Prohibit the server to advertise the stream on a public YP directory:
     -->
    <svrinfopublic>0</svrinfopublic>
</ezstream>

Next create a shell script to do the streaming that looks like this:

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#!/bin/sh

sleep 10

rtl_fm -f 162.55M -s 48000 | lame -s 48000 --lowpass 3500 --abr 64 --scale 9 -r -m m - - | ezstream -c ezstream.xml

Feel free to adjust the parameters, -s is for sample rate, --abr 64 uses an average bit rate of 64 --scale -9 boosts the volume, --lowpass helps filter out the high pitched noise.

Add this script to /etc/rc.local right before exit 0 so it starts on boot:

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#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi

screen -d -m  /home/pi/weather-radio.sh
exit 0

This starts the script in screen, when you ssh into the Pi, you can type:

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sudo screen -r

This attaches to the screen that was created, and then Ctrl+A, D to detach from it.  Don't type Ctrl+C as that will kill it.  Using screen is an alternative to using a service, but if you're good with service scripts, feel free to write one of those.  I had to add the sleep in there to give all the other services time to start up.

If all goes well you'll see this when you go into screen:

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Found 1 device(s):
ezstream: Connected to http://localhost:8000/tim273/edina
ezstream: Streaming from standard input
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Tuner gain set to automatic.
Tuned to 162802000 Hz.
Oversampling input by: 21x.
Oversampling output by: 1x.
Buffer size: 8.13ms
Exact sample rate is: 1008000.009613 Hz
Sampling at 1008000 S/s.
Output at 48000 Hz.

Lastly, add a new file called /etc/udev/rules.d/20.rtlsdr.rules and add this to it:

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SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", GROUP="adm", MODE="0666", SYMLINK+="rtl_sdr"

If you type lsusb, it will give a list of what's on your USB system, look for Realtek:

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Bus 001 Device 006: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

And then substitute the device ID of the RTL SDR dongle (obviously plug it into the USB port) for the ATTRS{idVendor} (0bda in this case) value and then the model in the ATTRS{idProduct} part (2838 in this case).  In terms of order, this one should probably be done before installing everything.  You'll need to reboot for it to take effect.

I'm using a Raspberry Pi 3 and the utilization is pretty good.

 [ You are not allowed to view attachments ]

If all works well, you should see this:

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I think that's it, let me know if you have any problems.

Thanks,
Tim

[satcop]

Thanks Tim;

I will give this a shot myself this weekend.  I think I have everything I need at this point.  I hope to get another feed up in addition to Manassas this weekend, Hagarstown MD using the SDR comes through quite nicely when properly filtered.

Bob

[vreihen]

I have a question regarding the standardization of stream names.  At least in these parts, each NWS office operates more than one transmitter within their service area...and each transmitter sends alerts for only its service area (and sometimes also relays them for neighboring NWS offices).

http://www.nws.noaa.gov/nwr/resources/NWR_poster.pdf

For example, NWS Albany operates 7 different "satellite" transmitters outside of their main Albany one - three in NY, one in western CT, two in western MA, and one in southern VT.  The one nearest to me (WXL37/Highland NY) also relays alerts from NWS NYC for my county, which doesn't have direct radio coverage from the NYC office.  Obviously, the transmitter location is important in the stream name.  If someone in southern VT put up an "Albany" stream, I would never hear the local alerts!

Currently, it appears that the streams are named in the format: State, City, Frequency.  I propose that the stream names be standardized as: State, NWS Forecast Office City, Transmitter City, Callsign, Frequency.  That should clarify what transmitter the stream is coming from, to clear up any ambiguities.

https://www.weather.gov/nwr/sites?site=KWO35

Also, I don't know if anyone has ever seen this resource, but it may be a great data source to hyperlink stream callsigns to so that listeners can see the exact areas/counties being covered.....

[Maumelle Weather]

Hi vreihen,

It is a very good question. My NWS office has 11 transmitters scattered around central part pf the state. This does not count the 4 other NWS offices that cover the 4 corners with their repsective transmitters. There are a total of 20 transmitters in my state.

Thank you for the links. I had not seen the .pdf in the first one. Downloaded that.  The second link, I see they finally updated it. I had downloaded all of the maps for Arkansas several years ago.

John

[Cutty Sark Sailor]

RE station names:
First, I'm working on new player which will link back to your website that's providing the stream.
   which I cannot accomplish in the current player, for some reason..
I think it best to use the Station "location" or "Station Name" for that particular transmitter that is being streamed, rather than the 'parent' station... which I'm trying to do...
For example, a 'repeater' goes down, and naming after parent would imply parent was down...

Only have a few stations, and already have one with NOAA giving "name/location" as one thing on their map, and two possibilities for either "location" or "Transmitter Name"...

This is what I'd like to see 'standard', I think... When they identify themselves, the tag it with something like "transmitting from' or 'located at' or something... a few say something like "NWS OFFICE in Louisville, transmitting from a station located in Frankfort..." or something else confusing... the "Frankfort, location Callsign, and Frequency" is what I think we  standardize with...

Whatcha think?
Mike

[tim273]

This is what I'd like to see 'standard', I think... When they identify themselves, the tag it with something like "transmitting from' or 'located at' or something... a few say something like "NWS OFFICE in Louisville, transmitting from a station located in Frankfort..." or something else confusing... the "Frankfort, location Callsign, and Frequency" is what I think we  standardize with...

Whatcha think?
Mike

So I think that's what I have going, if you look at my screenshot above my listed as:

Stream Name: Minneapolis, Minnesota Weather Radio
Stream Description: NOAA Weather Radio KEC65 162.55Mhz

Which is what is on that pdf map listed, does that look good?  Just trying to get some examples.

Thanks,
Tim

[tim273]

Thanks Tim;

I will give this a shot myself this weekend.  I think I have everything I need at this point.  I hope to get another feed up in addition to Manassas this weekend, Hagarstown MD using the SDR comes through quite nicely when properly filtered.

Bob

as an alternative, you could try this:

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rtl_fm -f 162.55M -s 48000 | sox -t raw -r 48000 -b 16 -e signed -c 1 -v 7 - -r 48000 -t .mp3 -c 1 -C 64 - lowpass 2000 | ezstream -c ezstream.xml

it uses sox instead of lame and seems to sound a little better.

[vreihen]

I wound up using the RadioReference command line, with a little bit of tweaking:

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#!/bin/sh

sleep 10
frequency="162.4735M"
##frequency="162.4985M"
lowpass="2200"
bitrate="8"
resample="22.05"

/usr/bin/rtl_fm -M fm -f ${frequency} -p 69 -l 65 -g 50 -s ${bitrate}k | /usr/bin/lame -r -s ${bitrate} --resample ${resample} -m m -b 64 --cbr --lowpass ${lowpass} - - | /usr/bin/ezstream -c /home/noaaradio/ezstream.xml

My test SDR was previously online running dump1090 for a few years, and it has stutters/hiccups from heat and old age.  I'll have to order two new SDR's, since I can pick up NOAA signals from two different transmitters/forecast offices and stream both.  I'm going to leave the stream running, with a disclaimer that it does have occasional dropouts and "Max Headroom" moments.

New York, Highland, NWS Albany, WXL37, 162.475Mhz (c/o hvtraffic.com)

http://nwr.hvtraffic.com:8000/wxl37

[satcop]

Well never worked with a Raspberry Pi before so this is becoming a bit of a learning experience.  Got the op system installed (that was the easy part).  I think I have the rtl fm software installed, although other than saying it is receiving I have no way to verify yet. (I know the dongle works because I had it working on more normal machine and using the windows version of SDR.  Now trying to get either icecast or sox working, but have run out of time today.  Downloaded but have to compile it, and there is no good docs that I can find at this point on the steps one must follow and the proper directories to put the files, so I keep tripping over myself.  I hate to say how long it been that I had to go through a step by step process to compile code,  and things have changed a lot since that time (I didn't have grey hair then among other things).

Anyway will pick this up tomorrow and see if I can't at least get it talking on my internal network.

Bob

[tim273]

Well never worked with a Raspberry Pi before so this is becoming a bit of a learning experience.  Got the op system installed (that was the easy part).  I think I have the rtl fm software installed, although other than saying it is receiving I have no way to verify yet. (I know the dongle works because I had it working on more normal machine and using the windows version of SDR.  Now trying to get either icecast or sox working, but have run out of time today.  Downloaded but have to compile it, and there is no good docs that I can find at this point on the steps one must follow and the proper directories to put the files, so I keep tripping over myself.  I hate to say how long it been that I had to go through a step by step process to compile code,  and things have changed a lot since that time (I didn't have grey hair then among other things).

Anyway will pick this up tomorrow and see if I can't at least get it talking on my internal network.

Bob

Hi Bob,

Actually you shouldn't have to compile anything, everything you need should be in the repository.

What you can do is type sox and it should tell you something like 'sox not found, type sudo apt-get install sox'  so whatever it is it should be in the repository.

[tim273]

as an alternative, you could try this:

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rtl_fm -f 162.55M -s 48000 | sox -t raw -r 48000 -b 16 -e signed -c 1 -v 7 - -r 48000 -t .mp3 -c 1 -C 64 - lowpass 2000 | ezstream -c ezstream.xml

it uses sox instead of lame and seems to sound a little better.

Ok, I substituted this:

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rtl_fm -f 162.55M -s 48000 | sox -t raw -r 48000 -b 16 -e signed -c 1 -v 6 - -r 48000 -t .mp3 -c 1 -C 64 - sinc -3.5k | ezstream -c ezstream.xml

The difference is I'm using sinc rather than lowpass, it's a more sharp cutoff.  More info here: http://sox.sourceforge.net/sox.html

[vreihen]

Now trying to get either icecast or sox working, but have run out of time today.  Downloaded but have to compile it, and there is no good docs that I can find at this point on the steps one must follow and the proper directories to put the files, so I keep tripping over myself.

As Tim wrote, all of the software is already built/packaged in the Raspbian package repository!  These three lines will install it all:

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install screen vim htop icecast2 lame libmp3lame-dev ezstream rtl-sdr sox

[satcop]

Thanks folks, I didn't see that they were already there in any of the docs, so as usual went off and made things a lot harder than I had to.  Now lets see if I managed to mess it all up because of trying to work things from scratch.  When you put together your script be sure to cover the unfamiliarity issue with the hardware.

Bob

[tim273]

Thanks folks, I didn't see that they were already there in any of the docs, so as usual went off and made things a lot harder than I had to.  Now lets see if I managed to mess it all up because of trying to work things from scratch.  When you put together your script be sure to cover the unfamiliarity issue with the hardware.

Bob

The beauty of the Raspberry Pi is you mess things up, just wipe your your SD card (or get another one) and start over.  I've done that many times.

[Cutty Sark Sailor]

For those not familiar PI, SDR, etc 
It can be done "simpler" if your mind is as stiff as mine is ... I got into this stuff 20 years too late, and have a severe brain dietary restriction on PI, raspberry or otherwise.

[vreihen]

It can be done "simpler" if your mind is as stiff as mine is ... I got into this stuff 20 years too late, and have a severe brain dietary restriction on PI, raspberry or otherwise.

This old dog has been working in the IT field for 31 years now, and he intends to make a bootable Raspberry Pi SD card image that will only require you to enter your wifi network password, pick a frequency, and enter a stream name.....

[Cutty Sark Sailor]

  darn... all I've got is a radio, weather pc, broadwave and an audio cable... but I did enough of that other stuff in my 35 year electronics career... if it's smaller than a 25 watt resistor I can no longer see it.  . Took 2 Star Wars films before I figured out Obi Wan wasn't a prototype OB2 regulator , which did resemble a light sabre prototype when fired up...  ...tried a couple of em stacked to run Blitzortung, but made too much noise... 

Gotta version 2 stream player about to go online... think got111 streams available now...

[vreihen]

... if it's smaller than a 25 watt resistor I can no longer see it.  .

I just had to use a magnifying glass to read a half watt resistor, and even then the colors of the bands were hard to distinguish.....

[tim273]

Now trying to get either icecast or sox working, but have run out of time today.  Downloaded but have to compile it, and there is no good docs that I can find at this point on the steps one must follow and the proper directories to put the files, so I keep tripping over myself.

As Tim wrote, all of the software is already built/packaged in the Raspbian package repository!  These three lines will install it all:

sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install screen vim htop icecast2 lame libmp3lame-dev ezstream rtl-sdr sox

Sorry I just remembered, if you are going to use sox to stream mp3, you'll need this too:

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apt-get install libsox-fmt-mp3