Sverre’s cheap VHF receiver: What is the cheapest receiver you can make for VHF? Here is a candidate where all you need to do to modify a small FM headphone receiver is to desolder one end of two capacitors, and connect a short cable with an antenna connector. See the full post on LA3ZA Radio […]
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Yet another Arduino clock
Sverre Holm blogged about his Arduino clock project: Its main features are: Controlled by a GPS module outputting data over an RS232 serial interface, and handled with the TinyGPS++ library Shows raw GPS data such as UTC time and date, position, altitude, and number of satellitess Shows derived GPS data such as 6-digit locator Finds local […]
DIY Powerpole voltage and current meters
Sverre Holm made his own powerpole voltage and current meters: Powerpole voltage and current monitoring is quite nice to have. One can buy commercial meters, but due to the availability of nice and cheap modules, it is very easy to make them oneself. To the right you’ll see my combined voltage and current meter as well as […]
Just good enough 10 MHz reference
Sverre Holm writes: Some time ago I noticed that the Ublox Neo-7M GPS has a 10 MHz output which is locked to the GPS system’s accuracy. Most people kept saying how useless it was due to excessive jitter unless it was cleaned up with a phase locked loop of some sort. But at the same […]
First 475 kHz WSPR decoding
Sverre Holm writes: Tonight I made the first successful decoding of WSPR on the 630 m band. What inspired me was all the talk on the Elecraft reflector on the new synthesizer which in addition to having less phase noise, also allows the K3 to go below 500 kHz. I don’t have that synthesizer, but […]
Low power longwave transmitter experiment
Sverre Holm writes: There are several low power transmitters around that can be purchased, but most of them only cover the mediumwave band and not longwave (153-279 kHz). Further they are quite complicated as the frequency necessarily has to be user settable. I looked for a simpler way to make a single-frequency transmitter and found […]
VHF Aircraft radio communications receiver
Dilshan Jayakody published a new build, a VHF Aircraft radio communications receiver: This is simple radio receiver project which is capable to receive aviation radio voice signals which are transmit between 118MHz to 138MHz in AM (A3E). We got initial idea of this project by reading Sverre Holm’s (LA3ZA) article about “cheap VHF receiver project”. Like […]
Temperature compensation for an Arduino ultrasonic distance sensor
Sverre Holm writes: Ultrasonic distance sensors can find the range out to 2-4 meters and are popular in e.g. robotics. Here I look at how the accuracy can be improved by compensating for the variation of speed of sound with temperature. It actually varies quite a lot in air and around 0 C it is: […]
Single-lever and ultimatic adapter
Sverre Holm writes: Here’s an adapter that emulates both a single-lever paddle mode and the ultimatic mode. It is meant to go between a dual-lever paddle and an iambic keyer. The adapter has been implemented in an AVR Butterfly in C and it is compatible with Morse keyers such as the one in the Elecraft […]
More projects using Altoids tin boxes as enclosures
In response to our “Disposable metal boxes make excellent shielded enclosures” app note post, Sverre shared some of his projects using the same enclosures. They are mostly RF projects, benefiting from the tin enclosure’s EMF protection. Nice post which triggered me to picture some of my own Altoid projects. Via the comments.