Saturday, December 1, 2012

Sending a text via ham repeater

Back in February I blogged about Voice Recognition for FM Repeaters.  This to my surprise made the July QST magazine.

I took this a bit further.  Now you can speak a spoken message over the repeater, and it will be converted to text and sent to the corresponding number that you entered on your DTMF microphone.

I made a very cheesy video, as video often explains it easier.  (I beeped out part of my number for some privacy, and you can hear my cellphone talking to the cell tower overloading my cheap microphone)

I am not going to give full details on how to do this here, as the point of this blog posting is:
1.) To show you that you can still implement cool stuff with ham radio..
2.) To encourage you think out side the box and mess with things till you stumble into a quick project such as this.

But to point you in the right direction, I will tell you that I created this using a combination of existing things that I have played with prior:

The repeater already has an IRLP board/connection.  This decodes the DTMF and invokes commands on the Linux computer that it is connected to.

Spoken message is converted using the Google Chrome speech input API that I explained in my prior post.

To actually send the text, I am using my Asterisk PBX coupled with a free Google Voice number capable of sending/receiving voice calls and text messages.  But you could just use a email / SMS gateway.

Special thanks to QST editor Steve Ford, WB8IMY for picking up my prior blog and putting it in print.

Friday, August 24, 2012

HSMM-MESH™ firmware ports

As announced by the QEX Magazine editor back in 2010, there are some groups of amateurs in Texas working together to implement a mesh network of HSMM nodes.

Think of this as similar to the D-Star network, but operating at a much higher data rate. The groups in Austin include ARES, Roadrunner Microwave Group, Texas Emergency Management, and Red Cross. There is also a fair amount of work being done in Dallas and Plano. Glenn Currie, KD5MFW, gave a presentation to a standing room only group at the Austin Summerfest this past Saturday, so interest is growing significantly.

The group doing the heavy lifting of developing software and hardware has been very busy over the past couple years. And there has been a large following.

Their custom ham radio HSMM-MESH™ firmware has been limited thus far to the Linksys WRT54G series of hardware.

There have been many requests to expand support for Ubiquiti devices and other hardware platforms. The WRT54G series isn't really in production anymore. But one can usually find them at thrift stores relatively cheap.

The Ubiquiti Bullet, Nanostation and other devices are readily available for about $75 each. Ubiquiti products use the Atheros chipset, where as Linksys WRTs, use Broadcom. Custom ham only channels and channel widths are possible with the Atheros chipset, but not currently available for Broadcom.

Fortunately Brian, KY9K of Yelm, Washington has come up with some development grade HSMM-MESH firmware that will support other devices:

HSMM-Mesh: Development Firmware with OLSRd v0.6.3
Mon Jul 30

I've uploaded my development HSMM-Mesh firmware to my server:

This is identical to the official HSMM-Mesh v0.4.3 release with two exceptions:

1) Integrates OLSRd v0.6.3 - fixes byte ordering in the secure module.

2) Domain changed from "" to just "us.mesh".

Since the new version of OLSRd fixes a byte-ordering bug that affects the WRT54G/GS units, this version will not interoperate with the official HSMM-Mesh release. The changes are all hidden under the hood and don't change the user operation.

The huge upside is that this version will talk to hardware from other vendors. I've got it talking to a Ubiquiti Bullet an a pair of D-Link DIR-825s on the bench right now.

If you've got time and some curiosity to spare, give it a whirl. Works great for every test I've done, but I'd like to get some extra eyeballs on it.


I fully expect this will become the default firmware image hams will gravitate to as they upgrade existing nodes.

In a related note. The Network World website has a recent entry titled "Home Wi-Fi routers could operate as emergency network, say scientists."

Friday, July 27, 2012

IPv6 & Ham Radio

Back in 1998, Naoto Shimazaki, 7L4FEP described an idea for use of IPv6 over the amateur radio in a document he presented to a TAPR Digital Communication Conference.

"IPv6 has huge address space and it supports real-time traffic. IPv6 realize new applications. For example, managing IPv4 address is not easy. It is possible to encode our "call sign" into IPv6 address. It enables us to managing IP address much easier."

You can read the whole thing here.

A few members from the Mesa Amateur Radio Club of Arizona took this to code.

"Club Members Jacques N1ZZH and Vinnie N1LQJ have developed a method of embedding a 2x5 (7 Character) callsign plus up to 185 nodes, plus 1 universal bit and three reserved bits in the 2nd octet, and a 16 bit amateur radio identifer at bit 24 of an IPv6 /64 Subnet address."

They announced;

"Tools for encoding and decoding amateur radio callsigns, up to 2x4 & 185 nodes, from IPv6 /64 subnets with Universal bit support and Amateur Radio Flag at the 24bit. Experimental RFC to IETF is being submitted for this proposed amateur standard."


IPv6 For Amateur Radio - EA4GPZ/M0HXM


Tuesday, June 12, 2012


Bob Witte, K0NR wrote an interesting column for CQ-VHF's Spring 2012 magazine issue.

It's titled "TRBO Hits the Amateur Bands."

Its about Digital Mobile Radio (DMR) sometimes called MOTOTRBO.

He points out that its a new digital standard that is gaining traction on the VHF and UHF amateur radio bands. He reports there are over 90 DMR repeaters up and running in the U.S with more planned.

DMR originated as a European Telecommunications Standards Institute (ETSI) standard.

The DMR Association is the industry body promoting adoption of the standard and includes these companies as members: Harris, Hytcra, Icom, JVC, Kenwood, Motorola, Tait Communications, Vertex Standard, and Zetron.

DMR takes a novel approach to spectral efficiency. The bandwidth of the radio signal is nominally 12.5 kHz with two signals sharing the channel via Time Division Multiple Access (TDMA). Simply put, two mobiles working through a DMR repeater share the channel by cycling their transmitters on and off in a synchronized manner. This is similar to how some cellular-phone systems handle multiple phones operating on the same channel. The cellular-phone base station controls the synchronization of the various phones so they do not interfere with each other. Similarly, with DMR the repeater has to synchronize the two mobiles using the same 12.5-kHz wide channel.

"A DMR installation looks a lot like a normal repeater system but with the benefit of two channels built in."

For those totally unfamiliar with TDMA, I recommending checking out my older blog titled "Understanding Digital," where I reference some Hak5 videos on Pulse Code Modulation. And the following week, Time Division Multiplexing (TDMA).

These sort videos give a good tutorial on how this works.

But if you really need the nitty-gritty, the TDMA time slots are 30 msec in duration.
In the 30 msec slot, the transmitter is required to ramp up to full power in 1.5 msec, send data for 27 msec, then power down in 1.5 msec.

For further good reading and information, I suggest reading K0NR's article. I believe this is the first printed ham article on DMR.

Sunday, May 20, 2012

Yaesu Digital?

Back in September 2011 at the Tokyo Ham Fair Yaesu presented a new line of digital ham radios. Then a short time later in late 2011, a new page on the Yaesu website titled "The Dawn of Digital Communications in the Amateur Radio World" appeared.

So here it is, a FT-1DR:

Their PDF talked a lot about C4FM. So many hoped they'd use IMBE and let it work with P25 gear.

They also talked about DMR (compatible with MotoTRBO), and we know the Vertex Standard branch does have DMR radios like the VXD-720 DMR HT.

However, there are 3 tiers in the DMR standard (described in ETSI technical standard TS102 361):

DMR Tier I products are for license-free use in the 446MHz band.

Under Tier I, ETSI has also defined two Tier-1 protocols:

DMR Tier-1 protocol utilizes 12.5kHz FDMA <---- br=""> dPMR protocol utilizes 6.25kHz FDMA

Both protocols provide for consumer applications and low-power commercial applications, using a maximum of 0.5 watt RF power. With a limited number of channels and no use of repeaters, no use of telephone interconnects, and fixed/integrated antennas, Tier-1 DMR/dPMR devices are best suited for personal use, recreation, small retail and other settings that don’t require wide area coverage and advanced features.

DMR Tier II covers hand portables, mobiles and base stations operating in the VHF and UHF allocations for PMR.

The ETSI DMR Tier-2 standard is targeted to those users who need spectral efficiency, advanced voice features and integrated IP data services in licensed bands for high-power communications. ETSI DMR Tier-2 calls for two slot TDMA in 12.5 kHz channels.

DMR Tier III products will support trunking operation.

Most savvy hams are familiar with Tier-2. This is what the above mentioned Vertex/Standard VXD-720 uses, as well as MotoTRBO.

According to a Yeasu FT1D sales flier picked up at Dayton :

C4FM 12.5 KHz FDMA.

Peak data transfer rate 9.6 kbps.

It can send a 320x240 pixel picture using a camera speaker mic. (as eluded to on the universal radio page)

It takes 20 seconds to send the picture over the air at 320x240, and 4 seconds at 160x120.

Because of display limitations, it can only save it in JPEG format to the Micro SD card slot on the camera. It can't display it on the radio itself.

What is interesting is the radio has a USB connector. This is for accessing the camera speaker mic as a webcam, and for firmware updates.

So in effect it's not really compatible with anything other than the cheesy radios designed for the license free PMR 446 band in Europe. But never fear, keep your anticipating eyes open for the Yaesu radio that will be compatible with Tier-2 DMR:

---From Page 14 of the Yaesu PDF---
At this point in time, Vertex Standard believes the C4FM (4-level FSK) FDMA or TDMA are the most suitable selections for Amateur radio applications. In early 2012, we will release a C4FM (4-level FSK) FDMA Handy-Talky and a Mobile transceiver into the Amateur radio market.

After our initial introduction, we plan to introduce a C4FM (4-level FSK) TDMA (2 slots) or TDMA Handy and Mobile transceiver into the Amateur market.

This is from page 15 of the Yaesu pdf.   The receiver audio output is the same as the IC-92.  And that is my biggest grumble with the IC-92.  In digital mode you better be in a quiet room, close to your radio.  In analog, however the audio out is okay.

Friday, May 18, 2012

UDR56K-4 Universal Digital Radio

UDR56K-4 New Product Release
Posted on May 18, 2012

For Immediate Release

NorthWest Digital Radio Announces New Universal Digital Radio at Hamvention® 2012

Dayton, OH – NW Digital Radio introduced the UDR56K-4 Universal Digital Radio at the annual gathering of Amateur (Ham) Radio enthusiasts. The radio, which has been designed to support digital data and digital voice needs of both amateur radio emergency service teams and digital radio experimenters The radio will support data rates from 4800-56K+ bps with selectable modulation methods including GMSK, FSK, and 4FSK. The UDR56K will operate in the 70cm band (420-450 mHz.) at up to 25 watts.

Bryan Hoyer (KG6GEU), President of NW Digital Radio said, “The UDR56K is a radical departure from legacy commercial radio offerings and brings a new, open platform, to the Amateur Radio community by providing a stable, integrated, software managed radio for digital communications combined with a tightly integrated Linux based computing platform in a compact package.”

The radio, which measures 4×6 inches and is topped with an eye-catching red colored heat sink, has none of the usual switched, knobs, dials, buttons, or switches. It has one Ethernet jack, four host USB ports, power, and antenna connections. All radio functions are controlled by software, using either a web browser interface or custom application.

NW Digital Radio has already integrated the Radio Messaging System (RMS) and D-STARi gateway and controller software. They are also in talks with noted software developers to provide additional digital radio protocols and applications on the UDR56K platform. Common Linux applications are easily installed using package management tools or may be compiled for the radio. Some applications of interest to the amateur radio community have already been tested, such as AX.25 networking, gpsd, Xwindows, bluetooth integration, wireless 3G/4G broadband, USB sound, and others.

“As we have talked to amateur radio operators, who are interested in digital communication for emergency communication or the development of new protocols, vocoders, and networks, there has been universal excitement fot the UDR56K,” according to John Hays (K7VE), Director of Marketing. Mr. Hays further noted that “Many have said, ‘can we pay now, to be at the front of the line?’”

Mr. Hoyer added, “We think we have a winner in this design, and anticipate a series of new products from our company. We want to build on the resurgence of ‘do it yourself’ activity. We will put the Amateur back in Amateur Radio!”

This device is not offered for sale, pending certification and approval by the FCC.

The UDR56K-4 has an anticipated release in the 4th Quarter of this year, with a target MSRP of $395.

For more information contact:

Bryan Hoyer, CEO

John Hays, Director of Marketing

NW Digital Radio Corporation is incorporated in the State of Washington.
Friday Harbor, WA

D-STAR is a protocol of the JARL and is also a trademark of Icom Corporation.

I am glad to see things like this.

Pitty they are limiting themselves with the current FCC data constraints. I wonder if the speed would be upgradable if those change or for foreign markets.

Tuesday, May 8, 2012

5 MHz bandwith support for OpenWRT

A number of you are experimenting with 802.11 OFDM on 70 cm with the Doodle Labs DL-435-30 and/or Xagyl XC420M.

I've been asking around on this, and here is what I've been told:

1) Check out the openwrt code and set up the build environment:

Use this SVN repository: svn://

2) Build the openwrt code and make an image:

3) Install the image:

Patch reset.c as follows, either using this patch or by editing it directly:

4) Rebuild the openwrt code and make another image.

5) Install the image on two APs and it should work!

Sunday, April 8, 2012

Customized D-Star Repeater

I have provided three simple bash example scripts. One says the time, another reports the weather conditions. And yet another will read back who was recently on your d-star repeater.

(I have since improved some of the quirky word concatenation from what is shown in the video.)

Special thanks to Kristoff, ON1ARF for his ambestream voice announcement toolkit.

Also to Scott, KI4LKF for his g2_link program.

To install this, first install ON1ARF's D-Star voice announcement toolkit, and download my premade AMBE library of files. (this also includes the three mentioned scripts)

To process DTMF; I suggest installing KI4LKF's g2_link program. (Alternatively ON1ARF's dtmf-rcq or a number of different DTMF decoding add-on options) Scott's g2_link will also give you the ability to connect to XFR and DCS D-Star reflectors. His g2_link program contains an easy to understand and modify to your liking shell script.

Sunday, February 19, 2012

Voice Recognition for FM Repeaters

Last year Google pushed version 11 of their Chrome browser, and along with it, one really interesting new feature- support for the HTML5 speech input API.

This means that you'll be able to talk to your computer, and Chrome will be able to interpret it. This feature has been available for awhile on Android devices, so many of you will already be used to it, and welcome the new feature.

If you dig around in the source code, you learn how the speech recognition is implemented:

Audio is collected from the mic encoded in FLAC format, and then passed via an HTTPS POST to a Google web service, which responds with a JSON object with the results.

Some Asterisk Telephony enthusiasts have been monkeying with this Google Speech API. This is how I first learned of it.

Interacting with a repeater thus far has been limited to DTMF to query the time, etc.

This API opens a whole new world to craft your own Siri like repeater system. Just set up a series of IF statements to grep/match the text returned.

You ask "What time is it?" It sees "time" and does a time lookup and speaks it back.
You ask "where is KB8ZXE?" it sees where and KB8ZXE and passes a query to and reports back that he was last 2.1 miles NorthEast of Green Bay".... etc

I've been experimenting with this on IRLP node/ repeater (147.075 MHz) here in Green Bay. It's really quite trivial to implement. I bet we are the first ham radio repeater to implement voice recognition.

Here is all you really need to get started:
 echo "1 SoX Sound Exchange - Convert WAV to FLAC with 16000"   
 sox message.wav message.flac rate 16k  
 echo "2 Submit to Google Voice Recognition"  
 wget -q -U "Mozilla/5.0" --post-file message.flac --header="Content-Type: audio/x-flac; rate=16000" -O - "" > message.ret   
 echo "3 SED Extract recognized text"   
 cat message.ret | sed 's/.*utterance":"//' | sed 's/","confidence.*//' > message.txt  
 echo "4 Remove Temporary Files"  
 rm message.flac  
 #rm message.ret  
 echo "5 Show Text "  
 cat message.txt  

Steve Ford, WB8IMY picked up on this blog and published it in the July 2012 issue of QST magazine.

{edit 2014}

This blog entry is over a year old is meant as a starting place for someone who has some Linux experience.  Since that time the Google speech API has changed a bit.  They block queries without a server key.

Step 0. Using an existing Google/Gmail account, join the Chrome-Dev Group.
Step 1. Create a new Project here (e.g. Speech Recognition)
Step 2. Click on your newly created project and choose APIs & auth.
Step 3. Turn ON Speech API by clicking on its Status button.
tep 4. Click on Credentials in APIs & auth and choose Create New Key -> Server key. Leave the IP address restriction blank.
Step 5. Write down your new API key or copy it to the clipboard.

Now for version 2 of the API you submit like so (replace with your API key):

 echo "1 SoX Sound Exchange - Convert WAV to FLAC with 16000"  
 sox message.wav message.flac rate 16k  
 echo "2 Submit to Google Voice Recognition"  
 wget -q -U "Mozilla/5.0" --post-file message.flac --header "Content-Type: audio/x-flac; rate=16000" -O - "" > message.ret   
 echo "3 SED Extract recognized text"  
 cat message.ret | sed 's/.*transcript":"//' | awk -F '"}' '{print $1}' | tail -1 > message.txt  
 echo "4 Remove Temporary Files"  
 rm message.flac  
 rm message.ret  
 echo "5 Show Text "  
 cat message.txt  

I have easily added code to existing IRLP and Allstar Linux computers.  IRLP or Allstar has the hooks to catch DTMF strings to invoke this application to record your spoken commands, and submit them for translation.  From there you can code keyword triggers a number of ways.  An easy example is to use grep.

 if grep --quiet time /tmp/message.txt; then  
  TIME=`date "+%l:%M %p"`  
  echo "the time is $TIME" | festival --tts   

Freely Available STTs:
Google STT

I highly recommend the "Building a Virtual Assistant for Raspberry Pi" book by Tanay Pant

{Edit 10/2018}
Chris Lam, KM6VGZ  - “Make amateur radio cool again”, said Mr Artificial Intelligence. - A project on building a speech recognition system for amateur radio communication.

Sunday, January 29, 2012

Doodle Labs DL435-30 Reports

A few hams have bought the Doodle Labs DL-435-30 transceiver.

The radio is capable of about 6 Mbps of data throughput utilizing a 5 MHz wide channel in the under-used 420-440 MHz ATV sub-band.

These were first made available in November 2011, so tests have been somewhat limited. However here are some initial conclusions:

At 20-30 feet using a 6 dBi gain omnidirectional antenna a couple different ham groups have seen 1/2 mile to 3/4 of a mile usable non-line of site mobile coverage using a 1/4 wave mag mount antenna. Both reports were in moderate to heavily mature tree neighborhoods.

Keep in mind at this low of a frequency, the height of the antenna will play a role to clear the large Fresnel zone and improve the performance.

The fact that you are not competing with your next door neighbors WiFi, makes these boards great for HSMM. If you can find a few hams in your area interested in it, there are bunch of possibility's for an OLSR network built on these things. Eliminating internet costs at repeater sites, repeater linking etc.

I'd appreciate hearing from other hams who are experimenting with this board wishing to share their reports.

Here is a short video that Kyle, N0KEW made:

Saturday, January 21, 2012

Minitor IV in the Ham Band

Our club repeater is capable of two-tone paging. It uses a CAT-1000 controller.

Many moons ago in the mid 90's we had some Minitor I's pagers re-crystaled for the repeater.

With narrow-banding affecting all public safety channels there will be scads of Minitor III and IV pagers out there, hopefully for cheap.

The municipalities will likely upgrade to the Minitor V as it's narrow band capable.

While the III and IV are frequency programmable, the ones that will be coming out of service will mostly be the 151-159 MHz subband (B) versions. My model: A03KUS9239BC

Never fear, if you use the engineer login function of the pager programming software (in Minitor4 PPS ver 1.8.1), you can edit the engineering data, and change it to a 143-150 MHz (A) bandsplit.  (the password is "Taipei")

As for the versions 159-167 and 167-174 I don't think these will lock down in the ham band.

This message thread on radioreference gives you good info in making your own Minitor Programmer. It gives you the pinout diagrams for the Minitors III, IV and V.

When I get a chance to test the sensitivity more in-depth I will edit this page with the results, and mods that I may deem necessary to improve the sensitivity.

Sensitivity is good. Near .4 uV

I haven't been able to track down a service manual, but this explains what to do if yours is not locking.

I have had success programming both M3 & M4's for ham freqs.