I hadn't built anything in a while. And a friend mentioned the desire to have something to check for proper deviation on various Echolink and repeater setups.
In a prior blog, Are you narrow or wide?, I covered more of the background.
There is a lot out there on this sort of thing.
FM Packet Deviation Meter
So I suggested we build this and hook it to a an old dedicated scanner. And after construction we calibrated it against a club IFR-1200 service monitor.
If you are not found of breadboarding, the above 73 article has an etched board available:
Here is a video that my friend made:
You'll be disappointed to know that Radio Shack doesn't carry the 15 vdc panel mount meter anymore.
Monday, August 29, 2011
Tuesday, August 23, 2011
A interesting Mesh like network was brought to my attention. It's called LifeNet.
More can be read here.
In the wake of major disasters, the failure of existing communications infrastructure and the subsequent lack of an effective communication solution results in increased risk, inefficiencies, damage and casualties. Current options such as satellite communication are expensive and have limited functionality. A robust communication solution should be affordable, easy-to-deploy, require low-to-zero infrastructure, consume little power and facilitate Internet access.
LifeNet is a WiFi-based data communication solution designed for post-disaster scenarios. It is open-source software and designed to run on consumer devices such as laptops, smart-phones and wireless routers. LifeNet is an ad hoc networking platform over which critical software applications including chat, voice messaging, MIS systems, etc. can be easily deployed. LifeNet can grow incrementally, is robust to node failures and enables Internet sharing. A novel multi-path ad-hoc routing protocol present at its core, enables LifeNet to achieve these features.
LifeNet exploits multihop communication to provide coverage over comparable areas with minimal infrastructure. Every device functions both as a host and as a router. Two devices close to each other communicate with each other directly, whereas communication between two far off devices can be relayed by low-power intermediate nodes in a multihop fashion.
More can be read here.