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Fred's Blog about Ham Radio, Python, Unix and more...

Mini APRS Weather Station

A year ago, I installed a system based on a Raspberry Pi Zero to manage my backyard lights. Since the system is installed outside in a weatherproof box, I have decided to install a DS1820 temperature sensor, send the data to APRS1, and use the APRS infrastructure to monitor …


Digital Voice Presentation

Every Thursday, the Portland Amateur Radio Club (PARC) organizes a series of conferences called Beginning Ham Radio. These conferences aim to teach new hams all the aspects that ham radio has to offer. This week, the club invited me to talk about the latest and popular Digital Voice modes. The …


Water Recirculation Pump Switch

When we re-did our house plumbing, we asked our contractor to install a water recirculation pump. A water re-circulating pump is used to circulate hot water so that any faucet or shower will provide hot water instantly upon demand. What is a recirculation pump? A typical home can hold between …


Learning CW

The Wordsworth method After watching George Allison's (K1IG) talk on QSO-Today describing his methodology to "head copy" Morse code, I have decided to give another shot to learning Morse code, often called CW in the ham radio word. According to George, high-speed operators who copy in their heads at speeds …


Field Day 2021

The 2021 Field Day was the first time member of the San Mateo Radio Club met in person since the pandemic. It was nice to see friends again after so long, but the most enjoyable part was to be in a group of people working toward the same goal …


80/75/40-meter antenna for Field Day

This year for Field Day, our club decided to build a new multi-band antenna for 80 and 40 meters. The antenna had to have enough bandwidth to use the entire band without using an antenna tuner.


Reflected Power and VSWR

Our main goal as Amateur Radio Operators is to make sure that as much of the power coming out of the radio as possible is radiated by the antenna. The maximum power transfer occurs when the power source, the radio in our case, and the load or the antenna are …


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