First long-distance HSMM-MESH link

Last week I was able to find some free time to attempt my first "long distance" MESH link.  The link was from my house to the hill next to Nielson Hall at Kirkwood Community College.  I finished modifying two routers to be Part 97 devices by changing out the reference crystal and mounted them in a couple of surplus Transeo TR-CPQ-19 CPE antenna enclosures.

For the link setup, I placed one of the Transeo enclosures on my front porch, bungeed to keep it stationary as I didn't have a second tripod available for this test. For the location at Nielson Hill, as I nicknamed it, I had a tripod with the other Transeo enclosure attached and did my best to aim the patch in the direction of my house:

To get the best chance of a link, I left both the routers set to +19dBm initial output power (which translates to 6.275W EIRP on both ends).  I haven't come up with a good method of aiming the flat patch antennas yet, so I took my best guess.

Lo and behold, it connected right away, average of 12dB SNR margin, not bad for the first attempt:

I then began to decrease the power level on my end of the link to see how far I down I could go and still maintain the link.  Decreasing in 3dB steps (cutting the power in the power each time).  Here is a screenshot at the 13dBm output level.

Then something unexpected happened, the link completely died.  With no-one watching the other end of the link I'm suspecting that the antenna shifted such that the pattern was no longer lined up with the hill.





This test was mainly to test the distance link before heading out to the Pigman Triathlon race, where we're planning on using this equipment to create a link that will be about 0.75 miles in distance.  I am now comfortable saying as long as we have line of sight the link should work just fine.

Making GPX tracks for APRSIS32

The 2012 Pigman Triathlon long and olympic course race is coming up next month in which I am slated to be a Net Control Station.  We will also be doing an experiment simultaneously where both Net Control locations will have an APRS display infront of them, linked by HSMM-MESH routers, to track the APRS equipped vehicle that will be trailing the last bike rider through the course.

One nice feature of APRSIS32 is that it will import a GPX file and display it on a screen, essentially creating a digital copy of the race map that has APRS posits (positions) in real time.  I have made these GPX files before for a race like this so I thought I'd outline how I make GPX files for importing into APRSIS32.

Software requirements:

• Google Earth
• GPSBabel

Step 1:
Open Google Earth, zoom into route start location

Step 2:
Create a "Path" along the race route by clicking points along the route.  You can get as detailed or as simple as you like.  The more detail, the better the map will look.

Here is Google's tutorial on making paths:
http://support.google.com/earth/bin/answer.py?hl=en&answer=1113936

Make sure to change the name of the path to something useful.

Step 3: 
Save the path as a KML file.

To do this, right click on path name on the left hand pane, Save File As....

or

File > Save > Save File As...

Choose KML format, give it a useful name and save in a spot you'll remember

Step 4:
Convert the KML file to GPX format

I use GPSBabel for this.  It's a popular program that will convert a ton of different formats dealing with GPS data to another format.

http://www.gpsbabel.org/index.html

Step 5:
Import GPX file into APRSIS32

To load a new GPX overlay, go to Configure > Overlays > Import GPX file...

Browse to the location you saved the GPX file to from previous step and play with the color, opacity, width, etc.

Now, is this the only way to create GPX files?  No, it's just the way I prefer and know how to do.  You can do it relatively easily with Google Maps and a tool called GMapToGPX, drive the route with your GPS and export the data or many other ways.

VoIP on HSMM-MESH

Since working on a HSMM-MESH™ installation at Mercy Medical Center here in town has been thrown into neutral for the time being, I've been focusing my attention on playing with VoIP over the mesh.

A while ago I acquired a Polycom IP500 phone to play with and it has been interesting to say the least in getting it working.

First off, the phone requires a FTP or TFTP boot server on the network to pull the application software and configuration files at bootup.  After many trial and error sessions I finally got the phone to boot from a TFTP server on my desktop and can make SIP phone calls directly between my computer and the phone, no SIP server required (after finding out that the sip phone address is SPIP@<ip_address>).

The only logical progression is to move the TFTP server from my computer to the HSMM-MESH™ router that the phone is plugged in to so I don't have to have a computer running to get the phone booted.  Of course, nothing is that simple.  Much consternation ensued again until I stumbled onto a forum post advising that apparently there is a bug in the Kamikaze 7.09 OpenWRT firmware that a dependency package for atftpd, libreadline, is not in the 7.09 repository so you have to install it manually from an earlier repository.  Easily done by executing the following command before installing atftpd:

ipkg install http://downloads.openwrt.org/kamikaze/7.06/brcm47xx-2.6/packages/libreadline_5.1-1_mipsel.ipk

The next goal will be to move the Polycom to a separate mesh node and try to make a call over the mesh.


Relevant links:
http://support.polycom.com/PolycomService/support/us/support/voice/soundpoint_ip/soundpoint_ip500.html

https://forum.openwrt.org/viewtopic.php?id=8495


ToTD: It would probably be a good idea to start keeping copies of any downloaded packages on a flash drive.  Never know when I'll have to do field work on this project without access to the Internet.

Inaugural post

I figure there are many projects that I'm working on that is of interest to others so I thought I might as well start a place to document and share them.  Bear with me on format and how it evolves, it's likely to change a lot.

73 de KC0ALC