Weak Signal Propagation Reporter (WSPR)

Adrian Motamedi, K3ADM

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

Weak Signal Propagation Reporter (WSPR) is an HF digital communication mode used for weak-signal HF radio communication between amateur radio operators. It achieves reliable communication by using low data rate and strong forward error correction coding (FEC).

WSPR was originally designed and implemented by Joe Taylor, K1JT, for probing potential propagation paths with low-power transmissions. The protocol is nicely implemented in a computer program.

So what is WSPR good for? WSPR can give insight into station performance without test equipment. Questions like… Despite having good SWR, does an antenna work well? What does its radiation pattern look like?

Talking to other hams, you might hear that a band is open, but then wonder how well your antenna works on that band. How do you know when exactly from your specific location, the band is open to your exotic DX destination and its vicinity?

While HF propagation software tools like VOACAP and Proplab-Pro give predictions, a WSPR beacon reveals what is happening now! You can see seasonal, day/night, and hourly propagation, and also monitor reported paths to different receivers – all nicely displayed on a map. WSPR software can even alert you at the best time for a QSO with your favorite destination. It can help you to adjust your antenna’s pattern or direction, or gather statistics about your beacon.

Adrian Motamedi, K3ADM, explains the WSPR protocol, then explain how he set up a Raspberry Pi computer as an ultra-low power (10mW) and low cost WSPR beacon. He explains how he designed, simulated, and measured a harmonic filter for the output. He tells how he time synchronized a standalone, Internet independent, WSPR beacon for less than $35.

Adrian’s presentation is available on-line.

FARS Winter Banquet - Coastal station KPH – its history, restoration, and modern operations

Richard Dillman, W6AWO via Zoom

This month’s meeting is scheduled to convene as an in person only meeting (NO Zoom Access) at the Blue Pheasant in Cupertino. Reservations are required to attend.

Parks on the Air

Clay Couger, N5YJZ and Scott Nacey, KK6IK

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

Clay Couger, N5YJZ, gives an overview of Parks on the Air activities, events, and mechanics.

Scott Nacey, KK6IK, talks about his recent experience, equipment, and lessons learned as he traveled to and activated numerous parks around the Bay Area.

Easy Home-Brew Yagi Design

John Portune, W6NBC

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

John Portune, W6NBC, speaks about designing and building Yagi antennas. Yagi antennas are parasitic array antennas made from an array of dipoles in which one element is driven and the others are parasitic i.e. present in the near field but disconnected from the feedpoint. These extra elements serve to shape the array’s beam pattern and result in a directional beam pattern.

John describes three simple “easy-to-remember” rules that let you create Yagi antennas that are at least 95% the equal of those that an expert antenna engineer can design or that on-line calculators can create. Low-cost home-brew examples are given.

SWR! Who Cares?

Kristen McIntyre, K6WX

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

Kristen, K6WX, talks about the meaning of standing wave ratio (SWR). Standing wave ratio has long been a boogieman in ham radio. Some make it the defining parameter of their station efficiency and performance. But why do we care? Does it have a role in designing our stations?

Kristen explores in some depth what SWR is and what it tells us and whether it really defines our station.

Digital Signal Processing (DSP) in Amateur Radio

Jeff Kabel AA6XA

This program was originally scheduled for May.

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

This meeting is one week earlier than usual. It has been scheduled for the 3rd Friday instead of the usual 4th Friday of the month due to Field Day. Be sure to put the correct date on the calendar.

Digital Signal Processing (DSP) is everywhere in modern communications systems. Jeff, AA6XA, gives a qualitative introduction to DSP. He covers basic DSP concepts (sampling and quantization) and give some simple examples. DSP can be math heavy but is presented here to not to require any difficult math. He gives you a feel for how DSP works and some of the ways it is important to wireless communications.

Antennas for Drone Applications

Keith Snyder, KI6BDR via Zoom

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom. Our speaker is presenting via Zoom this month.

Keith Snyder, KI6BDR, talks about the different antennas used for drones in the commercial world and a little about antennas for drone mitigation. Various antennas are used to fly hobby drones such as the DJI series drones. Basic coverages are around 2.4 GHz, 5.8 GHz, 1200 MHz, and 1600 MHz. The antennas on the drone and in the controller must work together seamlessly.

When contact is lost a drone will normally fly back using GPS to its original starting location. Improving this link can be done with higher gain antennas. But what if you want to reject a drone. Then you need drone killer antennas. We’ll look at these cases and explore the fun ways to detect and deflect drones. You either love them, or hate them.

Keith’s drone of choice is his DJI Mini 2 which has 4k video and he’s flown using a Yagi-Uda antenna extender on his controller.

Here is a video taken from Keith’s drone in action at Waikiki Beach in beautiful Hawaii: Friday Sailing 05 25 2024 DJI Mini 2 downtown Honolulu (youtube.com).

You can watch a video of Keith’s Zoom presentation on Youtube.

The K4ERO Loss Formula Untangled

Steve Stearns, K6OIK

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

In his talk last year, “Black Box Analysis of Microwave Networks,” Steve presented the riddle of the K4ERO loss formula that was published in QEX 2022 and QST 2023. K4ERO asserted that scattering parameter S21 of a black box 2-port device can be found by using a VNA to measure the input reflection of the device.

In this sequel talk, Steve solves the riddle and proves the published formula. Along the way he shows the method is not general. Certain assumptions are needed, which if violated defeat K4ERO’s method.

A forgotten, but better, method of determining S21 is shown. This method also uses input reflection measurements and a pair of Smith charts. This talk will illuminate “S” parameters and shows how to make and interpret measurements made with a NanoVNA, or any VNA.

FARS Annual Amateur Radio Home Brew Contest

K6YA

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

All presenters for this meeting must be in-person. No Zoom presentations accepted.

A free buffet dinner is served at this meeting. Enjoy a Gourmet Catered Chinese dinner from award winner Tien Fu. Chef and owner John Hwang has promised us an unforgettable meal.

Menu:

• Fried Rice Special
• Chow Mein Special
• Lemon Chicken
• Mongolian Beef
• Egg Plant with Szechwan Sauce
• Various beverages will also be available.

This meeting is about you. Yes you, our members and guests. Our Annual Amateur Radio Homebrew Contest is a opportunity to show off a project that you have worked on in the past year. Each participant has a few minutes to show and explain his project to our audience. No Zoom presentations accepted. Presenters each have a chance to win one of our four prizes:

$40 First prize
$30 Second prize
$20 Third prize
$10 Fourth prize

The Physics of Resonant Wireless Power Transfer

KG4UHM

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Jitsi.

Wireless power has a long history, dating back to Nikola Tesla’s research in the late 1800’s. After a long lull in activity, the field of wireless power has experienced a recent resurgence of interest and innovation. In this talk, we explore the physics of wireless power, the engineering challenges involved, and the new possibilities enabled by this technology.

Slot Antennas

John Portune, W6NBC

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

Back by popular demand, John Portune, W6NBC, talks about slot antennas: What they are. Similarities to and differences from conventional dipoles. Complementarity and reversal of the roles of electric field E and magnetic field H. Slot variations such as skeleton slots, folded slots, and cubical slots.

This talk is based on John’s Pacificon presentation and his Amazon Kindle/e-book “Slot Antennas for Ham Radio: The Forgotten Antenna.”

John’s presentation is available on-line.

Build Your Own DIY Wire Antennas: End-Fed, Off-Center-Fed, Baluns, and Ununs

Bert Henderson W6MSD

This month’s meeting is scheduled to convene at Covington. This meeting is also available on-line via Zoom.

This meeting is one week earlier than usual. It has been scheduled for the 3rd Friday instead of the usual 4th Friday of the month due to Christmas. Be sure to put the correct date on the calendar.

This month’s presenter is Bert Henderson, W6MSD. There are plenty of commercially-made HF antennas that you can buy. But why not save some dollars and build your own? Bert talks about DIY wire antennas that you can make yourself with an emphasis on end-fed and off-center fed antennas, both single band and multiband. He describes the antennas and matching/coupling transformers that he designed and built – how they work (theory of operation), and give a summary of sources for related information. He brings home-built hardware to show, and demonstrates how to do basic measurements using a nanoVNA.

Bert’s presentation is available on-line.