A blog and web site by K0TFU about amateur radio
Registration for the Zero Retries Digital Conference is now open! The conference will be held on October 16, 2026 at the Roundhouse Conference Center in San Ramon, CA. It’s colocated with, but separate from, the Pacificon conference held the same weekend. 〰〰〰
APRS services, sometimes called bots, provide useful capabilities to operators via APRS messages. I’ve been keeping my own personal list of useful bots and what their commands are. I’m throwing away my list. Craig KM6LYW introduced me to the APRS Service Registry . The registry is much larger than my list, and has the benefit of being a resource for the entire community. 〰〰〰
I have a proposal for a new APRS activity and supporting software called APRS On The Air. It brings the activator-and-chaser game of Parks on the Air and Summits on the Air to APRS. Read the proposal at https://aprsota.org . I’m looking for feedback before I build the software. 〰〰〰
The mad lads working on LinHT have posted a major update on their accomplishments with Rev B. These boards added: power management USB-C battery charging an RF power amplifier RF attenuators in the receive path a GNSS module With Rev B boards they have succesfully transmitted M17 over RF. They are on to Rev C with work on GNSS antenna improvements, audio codec changes, and more. This is amazing…
This elaborate description of what it took to replace the transparent LCD cover on a Elecraft KX2 is the funniest ham radio thing I’ve ever read. 〰〰〰
I just created and released a new piece of open source software called [kiss-tnc-bridge](https://github.com/kotfu/kiss-tnc-bridge). This daemon bridges Bluetooth KISS TNC clients to TCP KISS TNC servers. Here's why I created it, how it works, and how you can use it.
If you don’t have a ham radio license, or if you want to upgrade the license you have, there are many tools and study helps avaialble. I recently saw a new one called MyHamRadioStudy . It’s free and helps you study the questions from the current FCC question pools for the Technician, General, and Extra exams. Here’s some additional free alternatives: HamStudy and HamBook by…
Each spring, the [Salty Lizard](https://utahgravelseries.com/saltylizard) gravel bike race brings hundreds of bikers to Utah's west desert. Most of the course has no cell service, so amateur radio operators provide communication support for the 3 aid stations and drive the SAG vehicles which roam the course. I volunteered to help out at this years event. Here's how it went and what I learned.
Last year Cobra released the Trailblazer series of GMRS radios . Gratefully, they continued to use the same privacy codes as they have previously used. That means the mappings between brands of radios that I describe in my FRS/GMRS Privacy Codes Demystified deep dive work great with the Cobra Trailblazer 250, 450, and 500. 〰〰〰
Update: April 5, 2026: Zero Retries is back on substack at zeroretries.org . Zero Retries has recently moved to a new publishing platform and domain. If you haven’t updated your email subscription or missed the transition, it’s easy to resubscribe to this outstanding free email newsletter. Continuing the momentum from last year, Steve and Tina Stroh are planning the second annual Zero…