Doron Ben Chaim


The Colorado Emergency Reporting Net (CERN) is composed of a group of volunteer Amateur Radio Operators who monitor the various amateur 2 meter radio frequencies of the Colorado Connection Repeater INC. (COLCON) system.

These volunteers monitor the various frequencies of COLCON listening for requests from other Amateur radio operators who are-in-need of some form of assistance. This assistance is an alternative to regular commercial communication methods because the individual making the request does not have a cell phone, their phone is dead, and/or there is no cell coverage available.

The Colorado Connection is a 501(c)3 tax exempt organization that maintains free and open use to licensed amateurs of 15 interconnected VHF repeaters throughout the state of Colorado. Learn more about our repeaters here.

Except for Durango, all the linking is done via amateur radio. There are no phone lines, internet, or other non-ham links (Durango is an exception, using internet). With this combination of linking radios and remote sites that act as clients to other repeaters, there is a one way signal path across the system. In some cases the repeater’s audio is wired to a link radio and communications with another site is via a simplex link frequency or repeater pair. Duplex links are available between some repeaters, but most of the links are in one direction across the system at any given time.

One of the most significant characteristics of this system is the time it takes for transmitters to unkey across the system and return to an idle state, allowing a response in the opposite direction. Consider a conversation between Jim in Colorado Springs and Steve in Grand Junction. When Jim unkeys it takes a small but measurable time for each transmitter along the path to Grand Junction to unkey, drop its carrier, and allow the next link to follow suit. Only after each transmitter has unkeyed is Steve able to respond. When he begins transmitting, it takes more time for his audio to propagate back through each repeater and link transceiver in the chain back to Colorado Springs. If another user keys up on the eastern slope before Steve’s signal gains control from the other end, his response is lost.

What is ElectroSense?

The ElectroSense network is a crowd-sourcing initiative to collect and analyse spectrum data. It uses small radio sensors based on cheap commodity hardware and offers aggregated spectrum information over an open API.

The initiative's goal is to sense the entire spectrum in populated regions of the world and to make the data available in real-time for different kinds of stakeholders which require a deeper knowledge of the actual spectrum usage.

ElectroSense is an open initiative in which everyone can contribute with spectrum measurements and access the collected data. If you want to take part of this initiative, get involved now by setting up a sensor at your place or contact us to see how our data can help your business

A very cool semi-real terminal radar app. Written in Clojurescript targeting Node using shadow-cljs.

The First Responder Network Authority (FirstNet) of the United States was created under the Middle Class Tax Relief and Job Creation Act of 2012 (MCTRJCA) as an independent authority within the National Telecommunications and Information Administration (NTIA).[1] The purpose of FirstNet is to establish, operate, and maintain an interoperable public safety broadband network. To fulfill these objectives, Congress allotted $7 billion and 20 MHz of valuable radio spectrum to build the network.[2]
Several public-safety professionals and jurisdictions, along with commercial carriers, said the FCC should require interoperability between the First Responder Network Authority (FirstNet) and other Long Term Evolution (LTE) carriers and LMR networks, while FirstNet and its contractor AT&T said third-party interoperability is not outlined in the legislation that created FirstNet.

Comments were filed after the FCC last month requested input on petitions for declaratory ruling and rulemaking filed by the Boulder (Colorado) Regional Emergency Telephone Service Authority (BRETSA) in to ensure interoperability with the First Responder Network Authority (FirstNet).

Last year, BRETSA asked the FCC to issue a declaratory ruling and a notice of proposed rulemaking (NPRM) or notice of inquiry (NOI) on the same grounds presented in a request for clarification previously filed by the Colorado Public Safety Broadband Governing Body (CPSBGB).

“We do not believe Congress intended to award frequencies to FirstNet to enable it to become yet another silo leveraging market share on limited interoperability,” BRETSA said in its comments.

The agency said that the longer the commission delays clarifying the interoperability requirements of FirstNet and other public-safety radio systems, overseeing and actual progress toward full interoperability, and providing recourse for service or equipment providers met with refusals by other providers to implement full interoperability, the more full interoperability will be impeded by market incentives for providers to leverage market share through proprietary implementations of services, interfaces and features.
The OpenRepeater Project is the development of a low cost, low power, but a feature rich duplex Linux based amateur radio repeater controller using single board computers (SBCs) like the Raspberry Pi 2/3/3B+/4.
The goal is simple: replace my car battery with a coin cell (plus clever circuitry), and get the car to start at least once using only the energy from the cell.

  • Ted Yapo01/08/2018 at 18:54 4 comments

    I'm going to admit defeat. My last hope to get the car started was charging a NiMH battery of 4 AA cells (previously shorted) with a LiSOCl2 cell of 1.5Ah capacity.

    The NiMH cells read 1.33V after charging, which doesn't mean much.  Figuring that not much charge had found its way into the cells, I decided to start with the capacitor at 11V.  If I could boost this to around 14, start the engine, then show that the capacitor voltage was still above 11V, I'd consider it successful.

    Here's the log of the capacitor voltage:

    The initial almost-linear part was charging with my lab power supply at 11V, current-limited to 1A.  The voltage climbed to 11V and stayed there (it's not quite linear probably due to resistance in the wires).  After about an hour, I disconnected the lab supply, and put the caps on the boost converter driven by the NiMH cells (having been charged from the "coin cell").  I saw that it was working OK, and left to do some other things.

    When I returned, I found that the capacitor voltage had peaked at 12.4V, then started dropping again.  The NiMH cells were depleted.  This means that 1097J had been deposited in the capacitor by the NiMH cells.  Previous measurements had shown that 1500J are required to crank the engine.

    So, it's not going to happen from one cell.

    I have some more NiCd cells that were charged from LiSOCl2 cells and CR2477s, so I'll see if I can get the cap charged using the energy from multiple cells...

Welcome to Hackaday's Coin Cell Challenge. This challenge is all about building something that is powered by single coin cell battery.

Ignite your creativity. Try out low power, whether it is new to you or anyone else. We want to see some amazing power sipping attempts and for you to document it all. Share what worked and what didn't. Extra wrencher points if you share photos of destroyed batteries pushed too far during experimentation.

In short, do something awesome with a coin cell. But we also have special prizes for the examples in three different achievements: Lifetime Award, Supernova Award, and Heavy Lifting Award.

The Winners Have Been Announced!

Congratulations to all of the winners, and honorable mentions!

Awards and Prizes

The top 20 projects will be rewarded with $100 Tindie Credit plus three additional cash prizes of $500 each for the following special achievements:

  • Lifetime Award: Running the longest on a coin cell.

Lifetime Award: Light Level Geolocator

A light level geolocator powered by a CR2032 is the winner of the Lifetime Award with a cash prize of $500.

  • Supernova Award: An exciting display of power -- battery lifetime be damned.

Supernova Award: Coin Cell Powered Railgun

A railgun powered by an LIR2032 cell wins the Supernova Award with a cash prize of $500.

  • Heavy Lifting Award: Disbelief. Think: "you can't do that with a coin cell battery."

Heavy Lifting Award: Coin Cell Powered Screwdriver

Driving screws into a 2×4 using power from a CR2477 wins the Heavy Lifting Award with a cash prize of $500.

W0TX/DRC Tech Committee Meeting Location:

Westminster Room, #1566,+Golden,+CO+80419

Just before Hearing Room #1, turn left at the green "CONFERENCE ROOMS" sign, go to the end of the hallway, turn left at the "1556 thru 1565 Conference Rooms" sign, then immediately turn right at the next hallway, room 1566 will be on the right, lock if the door is locked.