09 Aug

BBHN NoVa Mesh



Broadband-Hamnet (BBHN) is a peer-to-peer mesh network that ham radio operators are trying to build out across the country. We need help in the northern VA to install mesh nodes accross the region. 




There are many motivations for why hams do what we do.  My motivation for helping out with this effort is fairly simple: why not, seems fun.  Turns out the first 6 channels (1-6) fall under the ham radio allocation. This means hams can use this equipment under Part 97 rules that allow higher gain antennas & power levels. 


I have installed a UBNT BulletM2-Ti and a TP-Link TL-ANT2412D 12dBi vertical antenna on the roof at about 75feet. This set-up cost me just over $100. Many hams are using old Linksys APs with home made antennas to keep the costs down. Check out the supported hardware list as well as firmware you can use to flash the hardware & get started right away. 


At the moment we have three nodes: 




Equipment I purchased for this project. I've been wanting to by UBNT gear for some time now anyways. :)




The UBNT Bullet M2 can be connected directly under the vertical antenna. I'd recommend some effort in water-proofing this interface.




NoVa mesh node installed installed in Chantily, VA operating 24/7.





If you are interested in learning more check out these two sites:


Amateur Radio computer compatible Networks


Call for Help

If you are in the northern Virginia area and would like to help out or learn more, contact me via email at KE4HGN @ that email service gmail likes to run.  We are looking for people who can install mesh nodes or might have roof-top access to facilities in the region.  If you can provide access to a high altitude roof-top, we'll provide the hardware & help to get it installed.  


I learned last week that Oshpark does not sell gift cards. I think it was fitting to design our own.


I've tried many different methods for storing components for projects @ home. In the past I didn't have the space or dollars for a huge set of Lista cabinets. I've tried small drawer cabinets, envelopes, tiny SMD snap boxes, & modified tool boxes. Today my favorite method is simple notebooks with plastic currency collector sleeves. Not bad for $0.17 per page.



#EEnotebook concept




Works great for passives!




Works OK for ICs and large components. If you look close you'll see electrical tape holding the sleeve opening down. I found it simpler to lock loose components like transistors in place by putting them on electrical tape.




Rather than printing or writing labels for the components, these sleeves have a slot that are perfect for the Digikey or Mouser inventory label. (scissors required) :)




In a few months I'll know if this is a great idea or another annoying component storage concept. I'll update this post as soon as I decide.


I've been using the rtl-sdr for many months now. It's a great capability for the cost!


I use it as as a general purpose spectrum analyzer, ham radio receiver, scanner, & RF capture tool to record captures into Matlab.


The USB flash drive form factor didn't work for me & I wanted something a bit more durable. I've been using Mammoth Electronics die cast aluminum enclosures lately because they are well priced & come in many fun colors.


The electronics fit quite nicely in a 1590A enclosure. 



I think it looks pretty good on my bench with a whip.



I've been getting used to placing the rtl-sdr close to the antenna & using a USB extension cable to get out to it. In the image it is hiding behind my DIY Bluetooth speaker on my barbecue grill.




Placing the rtl-sdr has certainly helped with interference getting into the (lack of) RF front end.


To take this project to the next level you could make it water proof or add a ferrite bead on the noisy 5V coming from the USB to clean things up even further.



Last year I built a few Build Buttons for my firmware team. If you are going to build/debug all week you might as well have fun doing it.


I used a Teensy as USB HID to send F7 when the B0 signal was shorted. I then configured Eclipse to Build All & Run Debug on a F7 key entry.


This is a simple fun project & I'm getting used to slamming the Build Button while I'm hacking up some FW.


If you want to take this project to the next level... consider adding a battery & Bluetooth module to cut the cord! 


Merry Christmas 2013






Merry Christmas!  


Rachel & Apolo, I hope you two enjoy the gift! - Mom, Victor, & Sarah 


Note: The gift is for three months since I'm told it snows in Pitt through March. Crazy right?



Edwin H. Armstrong born on this date in 1890. His inventions include the regenerative circuit, superheterodyne and FM. Ham radio call: GS (yes, that’s what he assigned himself on SPARK)


“Anyone who has had actual contact with the making of the inventions that built the radio art, knows that these inventions have been the product of experiment and work based on physical reasoning, rather than on the mathematicians' calculations and formulae. Precisely the opposite impression is obtained from many of our present day text books and publications”- Major Edwin Howard Armstrong.


Last week I was curious about the signaling used by my garage door opener to its wired remote.  My garage door opener has a wired remote panel with three functions:

  1. light on/off
  2. open/close door
  3. lock.

Below are scome oscilloscope shots with my comments of how the signalling works in case someone else out there is also interested.  The motor control units sends an inverted periodic pulse train. The multiple functions are controlled via modulating the pulse width.  


This data might be interesting if you wanted to add an RFID keypad, improved & more satisfying wired panel, or BLE keypad. Find me on Twitter @roteno if you build something & found this useful.   



IDLE STATE - normal state of the system while unlocked & not being operated by a user 

Garage Door Signaling - IDLE STATE

Period: 12mS Vmax: 24V pulse width: 190uS 


IDLE LOCK STATE - puts the system into a idle locked state that disables the wireless keypad open/close door functionality. Wired door open/close functionality continues to work. 

Garage Door Signaling - IDLE LOCK STATE

Period: 200mS Vmax: 24V pulse width: 100mS (idle state 12mS period & 190uS pulse width are pressent as well) 


LIGHT ON / OFF - toggles the internal light on & off

Garage Door Signaling - LIGHT ON / OFF COMMAND

Period: 12mS Vmax: 24V pulse width: 2.6mS 


LOCK ON / OFF - toggles the lock state on & off

Garage Door Signaling - LOCK COMMAND

Period: 99mS Vmax: 24V pulse width: 24mS 


DOOR OPEN / STOP / CLOSE - toggles system between open garage door, stop door movement, close door   


Short the two wires.  Pulse width > 200mS. 



07 Jul

Victor 86D




After some time using needle nose pliers to change the setting on my old general purpose digital multimeter (DMM) I decided I needed a new one.

The one I decided to go with is the Victor86D with USB logging features. 



Fluke 287 vs Victor 86D


Fluke 287 vs Victor 86D


Fluke 287 vs Victor 86D

07 Jul

Bearcat 8 Update



I found an old radio I used as a kid in the attic: an 8 channel crystal controlled Bearcat 8 scanner. It was a museum piece when I got it but I loved how simple it was to use (if you had the requisite crystals).


I loved how the LEDs scroll in scan mode & remember how crisp the audio was. I'm curious if there is any interest for a modern day equivalent? 10 channels, slow scan rate, good audio, much smaller, & super simple control.


If there is enough interest perhaps I'll build & sell them. Let me know what you think on Twitter (@roteno).