Fred C (W6BSD)
Just a quick note for anyone who needs to convert between QRA (Maidenhead) locators and geographic coordinates. We've set up a simple, no-frills web tool at bsdworld.org/QRA-Locator. It's a lightweight page that does exactly what it says in the title: Earth Enter a QRA locator (like CM87VL) See...
Fred C (W6BSD)
Info This article was also posted in French on my club's website F6KOP The objective of a choke balun is to reduce RF current flowing on the outside of the coaxial cable, thereby improving the symmetry of the radiation pattern and suppressing radio-frequency interference (RFI). The target values...
Fred C (W6BSD)
This letter was written by Frank (F4AJQ), and sent to members of the French club F6KOP. The text was originally in French. I translated and posted it here as a reminder of what Ham Radio is about. Good evening, KOPains1 I often browse Facebook and am frequently surprised by what I read about our...
Fred C (W6BSD)
Stop Guessing and Start Whispering! I recently moved to a new house and had to rebuild my antenna setup from scratch. Like most people, I checked the SWR to make sure my radio was working well, but a good SWR only tells part of the story. It doesn’t show where your signal actually goes after it...
Fred C (W6BSD)
Introduction VHF and UHF1 bands form an essential part of the radio spectrum, supporting everything from amateur radio communications to public safety networks. These frequencies offer reliable local coverage and occasional opportunities for impressive distance work when conditions are favorable....
Fred C (W6BSD)
Unlocking the Power of Repeater Networks Amateur radio operators understand the excitement of connecting with others, and repeater networks incredibly enhance that connectivity. I want to share my experiences with several repeater networks: CARLA, N6ICW, WB6ECE, and the WIN System. Each of these...
Fred C (W6BSD)
Voice communication methods such as SSB, AM, and FM are fundamental to the hobby. Digital modes present a captivating and often more efficient way to communicate, particularly when signals are weak or there is interference. These digital modes convert your text or voice into digital signals that...
Fred C (W6BSD)
Most people managing a repeater or using a Pi-Star open-spot at home want to automate the connection to a specific reflector to ensure they don't miss a net. To automate that task, they look online, and the internet tells them to insert a line in the file /etc/crontab to tell the Pi-Star to link...
Fred C (W6BSD)
If you've experimented with HF antennas, you've probably encountered the Half-Wave End-Fed (HWEF) antenna. It's popular for its simplicity, ease of deployment, and ability to resonate on multiple bands. In my previous post, I outlined several significant drawbacks of HWEF antennas, including their...
Fred C (W6BSD)
Half-wave end-fed (HWEF) antennas have gained popularity among amateur radio operators for their simplicity, versatility, and ease of installation. While they have a few notable benefits, they also have many problems that make them less than ideal. Here's why I'm not totally sold on HWEF antennas....
Fred C (W6BSD)
RG-231 Coaxial Cable In my previous article, I've been exploring the details of total losses in transmission lines and the extra losses caused by SWR1. I've created a loss calculator to help users effectively determine their cable losses. This project required meticulous data collection from...
Fred C (W6BSD)
Heliax Coaxial Cable The coaxial cable is critical when setting up a radio communication system. This cable transmits RF signals from the radio to the antenna. We use coax cables because they have a conductive shield surrounding the inner conductor. This shielding minimizes electromagnetic...
Fred C (W6BSD)
In my last article, I explained how to measure the resonant frequency of an LC circuit by simulating a grid dip meter using an antenna analyzer or a NanoVNA. This method is convenient when you only have an antenna analyzer. However, a NanoVNA has two ports, and you can use an S211 measurement to...
Fred C (W6BSD)
Old HEATHKIT Dip Meter In previous years, amateur radio enthusiasts heavily relied on dip meters as an indispensable tool for circuit testing. These meters, also known as grid dip meters, were variable-frequency oscillators with a coil that could be placed near the tested circuit. When the dip...
Fred C (W6BSD)
It's important to keep an eye on space weather for effective communication, especially for a ham radio operator. Solar activity can have a significant impact on how radio waves travel. I'll share some essential graphs to monitor from my website: http://bsdworld.org/. Note The graphs provided on...
Fred C (W6BSD)
I discussed an educational club activity in my previews blog post. The goal was for the club's junior members to build a Delta Loop antenna. I gave them the minimum number of instructions, and they had to figure out all the antenna dimensions and the mechanical structure to support the loop....
Fred C (W6BSD)
Now and then, some folks from the San Mateo Radio Club get together at the park to work on a ham radio educational experiment. We cover operating HF, experiments with feed lines, building antennas, or any other ham radio project. These meetings aim to demystify and familiarize beginners and...
Fred C (W6BSD)
On repeaters, in Ham Meetings, or when people talk about electricity in general, I hear the sentence, "It's not the voltage that will kill you, but the current." Zap! The idea that "current, not voltage, kills you" oversimplifies electrocution. While current is crucial, voltage plays a critical...
Fred C (W6BSD)
The Hustler 4BTV antenna is a vertical HF antenna known for its efficiency, durability, and versatility across multiple bands. However, if you want to use that antenna to tap into the 17-meter band, you'll need to modify it by adding a dedicated wire. This blog post describes how to include the...
Fred C (W6BSD)
SMRC Radio Scavenger Hunt The San Mateo Radio Club is organizing a ham radio scavenger hunt. The event will be held in San Mateo on October 7th 2023 at 9 a.m. The scavenger hunt starts at the following place: https://w3w.co/loving.drag.mobile A radio scavenger hunt can be a fun and engaging way to...
Fred C (W6BSD)
A ground-plane antenna, also called a quarter-wave or a monopole antenna, is widely used in radio communication systems. It is relatively simple in design and consists of a vertical conductor, typically a metal rod or wire, mounted above a conducting surface known as the ground-plane. The...
Fred C (W6BSD)
Ham radio repeaters play a crucial role in extending the range and enhancing the clarity of your amateur radio transmissions. They act as relay stations, receiving signals on one frequency and retransmitting them on another, allowing for broader coverage and improved reception. Whether you're a...
Fred C (W6BSD)
Often, ham radio operators who just got their general license are confused about which band to use. Here's an explanation of each HF band's typical usage and characteristics. 160 meters (1.8 - 2.0 MHz): This band is known as the "Top Band" and is suitable for long-distance communication,...
Fred C (W6BSD)
FT8 Commander Because this might be a controversial subject for some, please read the note below before reading the rest of the article. For countries outside of the United States of America, consult your local rules. Note FCC Part 97 about station control. §97.109 Station control. (d) When a...
Fred C (W6BSD)
Radiosonde A radiosonde or weather balloon is an instrument with a series of sensors to measure the atmospheric parameters from ground level up to an altitude of 35,000 meters (100,000 feet). Radiosonde Launch (NOAA) The balloon carrying the radiosonde is made of latex, neoprene, or polyethylene...
Fred C (W6BSD)
A couple of weekends ago, I took my trapped vertical antenna apart to clean it up, ensure every component was in good working condition, and fine-tune it. While working on the antenna, I noticed that the Common Mode Current choke box had a crack due to the hot California summer sun making the ABS1...
Fred C (W6BSD)
The Hustler 4BTV For most of my HF traffic, I use a Hustler 4BTV antenna. The antenna is a vertical trap antenna capable of working the 40, 30, 20, 15, and 10-meter bands without using a tuner. I installed this antenna five years ago, and it has always worked fine, with a reasonable SWR on all the...
Fred C (W6BSD)
I have developed a Telegram bot to help ham radio operators find solar and propagation data. Telegram Screenshot Telegram is an instant messaging application like iMessage, Google Chat, or WhatsApp focusing on security and privacy. I have used Telegram for this bot because Telegram provides a very...
Fred C (W6BSD)
Leslie Moxon, G6XN, invented a two-element in the 1950es, named after him. Less Moxon published an article in a QST magazine issue from 1952 titled Two-Element Driven Arrays describing his antenna. Since then, the Moxon antenna has been referenced several times in the QST magazine.123 The Moxon...
Fred C (W6BSD)
A Double Bazooka Antenna is a broad-banded half-wave Antenna. This antenna can operate efficiently across an entire band without needing an antenna tuner. In the 1940es, the MIT staff designed and developed this antenna as a radar antenna for the military. Like a dipole, the Double Bazooka is a...
Fred C (W6BSD)
It is often helpful to run tests and take measurements without connecting an antenna. Ham radio operators or anyone who builds or experiments with radio transmitters should have a good dummy load. Since I didn't have such a device, I decided to make one. Dummy Load In radio, a dummy load1 is a...
Fred C (W6BSD)
In my last article, I showed how to measure an inductor using a known capacitor. This method could be used to measure a capacitor using a known inductor. This post will demonstrate a better and more accurate way to measure a capacitor using an oscilloscope. Usually, a capacitor's value is printed...
Fred C (W6BSD)
Resistors, inductors, and capacitors are passive components used in every electronic circuit. Usually, the value is marked on the resistor or capacitor, either as a color code or a number. Often, inductors have no markings, especially those with a ferrite core or an air core. To measure their...
Fred C (W6BSD)
People think that all wires are the same and that any cable should be OK to power their rig. This is far from true, especially when you want to power your radio using a battery. This article focuses on installing a mobile radio or installing a battery backup for your shack, but everything...
Fred C (W6BSD)
I gave a presentation on antenna modeling software to a couple of clubs in California and Oregon. From the physical antenna design to the matching network, we designed the antenna live with the participants. Here is a little more about the talk: During the first part of the talk, we go through...
Fred C (W6BSD)
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 the weather. DS1820...
Fred C (W6BSD)
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...
Fred C (W6BSD)
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...
Fred C (W6BSD)
Field Day 80/40-meter antenna 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. Smith Chart dipole on...
Fred C (W6BSD)
The state of California and San Mateo County have eased COVID restrictions. It is why the San Mateo Amateur Radio Club has decided to have their Field Day operation at the usual location, Beresford Park. Dipole 40-meter branch The club's Field Day committee1 decided to build a new multi-band...
Fred C (W6BSD)
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 a match. When the source and the load...
Fred C (W6BSD)
Is Resonance required? Important This is an extract from the ARRL Antenna book1 Please recognize that an antenna need not to be resonant to be an effective radiator. There is in fact nothing magic about having a resonant antenna, provided of course that you can devise some efficient means to feed...
Fred C (W6BSD)
DUDE-Star is a software developed by Douglas McLain (AD8DP) that connects to D-STAR, Fusion, NXDN, P25, Allstar, and even to the new digital mode designed by and for ham radio operators: M17. DUDE-Star includes a software IMBE and AMBE vocoder for encoding and decoding, but it can also use any...
Fred C (W6BSD)
Many ham radio operators are interested in EMERCOM1. It can be useful to have a reliable source of weather information during an emergency. Some radios come with the NOAA2 frequencies already programmed in the memory. Hams have also programmed the following channels in their radios: NOAA weather...
Fred C (W6BSD)
A few months ago, I wrote a blog post asking the question "Where are all the hams?". For that blog post, I generated heat maps of regions of the world showing WSPR1 activity. A few days ago, I sent an email to Philip Gladstone, from the PSK Reporter's website, to ask him if the archive of all the...
Fred C (W6BSD)
PIRIM Raspberry-Hat My friend JC (W6IPA) and I have created PIRIM, a Raspberry-Pi Hat for Allstar1, Echolink2, or any digital mode. It is a versatile board that can be used in multiple configurations. The primary use for this board is with the SA818 radio module. Before you can use it, the SA818...
Fred C (W6BSD)
Over the years, I have made several Allstar, Echolink, and APRS nodes1. A few months ago, my friend JC (W6IPA) told me he wanted to build an Allstar node. I gave him this piece of advice: if I had to make a new Allstar node, I would create a Raspberry-Pi hat with a radio module like the SA818....
Fred C (W6BSD)
Over the last few months, I have participated in an increasing number of discussions, either on local repeaters or in zoom meetings, about newly licensed hams interested in operating in the HF bands. Two main questions kept coming back: what radio to buy and what antenna to use. It is why I have...
Fred C (W6BSD)
A few months ago, I installed a new 40 and 80-meter dipole. My shack and my antennae are on opposite sides of the house. My feed line goes through narrow spots inside the house and runs underground from the house to the antenna. Installing a new feed line for this new antenna was not an option...
Fred C (W6BSD)
When I build or install a new antenna, I always run a series of tests. Like everyone else, I look at the resonant frequency and SWR. But to see how the antenna is performing, I run WSPR1 for a few days. Then I use the data collected by WSPR Net to draw the graphs that can be seen in my previous...