The 30th Four Days In May (FDIM) 2026 Symposium - The Biggest and Best QRP Event in the World!

Online registration is now open through Sunday, April 26th: FDIM 2026 Registration

For those who are new to the club or have never made the Four Days In May event, it is the annual gathering of the QRP Amateur Radio Club International. It is held in the Fairborn Ohio DoubleTree Hotel May 14 - 17 2026, beginning the day before the opening of the Dayton/Xenia Hamvention, and has events that take place during the evening of the Hamvention weekend. Hams who come to Dayton for the Hamfest can come one day early, and enjoy all that both events have to offer.

A discount block of rooms will be available at the DoubleTree for FDIM attendees. Upon registering, you will be emailed a link for reservation of these rooms.

At Four Days In May you are likely to run into your favorite QRP Quarterly writers, designers of the QRP equipment you enjoy, and friends you have worked on the air. You will see the new kits and rigs from QRP vendors, and have a chance to check out some amazing homebrew projects. And you will have the opportunity to converge on Saturday evening for our annual Awards Banquet, and celebrate the successes and honors of the QRP community.

We have a great roster of speakers lined up for our Thursday Symposium beginning at 8:00 AM. See the list posted below:

Ashhar Farhan, inventor of the BiTX radio, and proprietor of HFSignals, will be bringing along samples of a new kit which he will be giving away to attendees of the Thursday Symposium. He will then be giving a presentation Thursday evening at 7:00 PM in the DoubleTree Amphitheater to describe this new kit and other innovations from the past year.

Thursday evening is our Vendor Night beginning at 8:00 PM, where you will have the opportunity to see and purchase new kit offerings from our QRP community.

We will once again be hosting Rex Harper W1REX and his FDIM Buildathon beginning Friday afternoon. Details are still being sorted out, so check the QRPARCI.org website in the weeks ahead. 

On Friday May 15 at 7:00 PM, Hans Summer will be presenting a technical topic in the DoubleTree Amphitheater on a subject yet to be announced, but be assured, you will not want to miss it!

Friday evening at 8:00 PM will be Club Night where our QRP clubs will have representatives present to answer your questions about their activities and offerings. Later that evening we will have our 2026 FDIM Transmitter Efficiency challenge - see the rules elsewhere in this issue. Be sure also to bring your latest homebrew projects to enter in our Homebrew Contest.

On Saturday May 16, our event culminates in our annual Awards Banquet. Please join us as we recognize the best of our QRP hobby.

The goal of Four Days in May is to pack as much QRP fun as possible into a brief four day weekend. The one thing that would make it even more fun would be to have YOU attend, too! If you have never been to FDIM before, make this the year to do so!

David W. Cripe, NM0S

 

Online registration is now open through Sunday, April 26: FDIM 2026 Registration

FDIM is being held at the same physical location as last year but the property has a new name:

 
DoubleTree Fairborn (formerly Holiday Inn)
2800 Presidential Dr.
Fairborn, OH 45324

 

NOTE: Because of the extremely high demand for a limited number of rooms, we will email the DoubleTree registration link after receiving and processing your QRP Store transaction for a symposium or banquet reservation.

Below is the pricing for 2026 FDIM: 

  • Symposium with Proceedings Book  - $40.00 per person  (Includes Lunch)
  • Banquet - $45.00 per person
  • Proceedings Book - $15.00 per book
  • Zoom Only Link - $12.00 per person - Zoom Link will be emailed to you a few days before FDIM

Using the QRP ARCI Store will be the preferred method of reserving your spot at the conference and/or the banquet, including receiving the hotel block registration code.

FDIM 2026 Tentative Speaker Lineup Announced

Harold Smith A Homebrewer's Journey -- How I got to where I am.

A QRP Ham's History. Where I started, how I learned what I learned.  The ups and the downs. Learning from building more stuff that didn't work the way I wanted than stuff that did.
Anthony Luscre Getting On The Air- Life is NOT Too Short for QRP Operating, If You Know a Few Tricks Unlike other areas of Amateur Radio, QRPers often spend a significant amount of time building their own transceivers. Many create wonderful projects, while others assemble kits; however, getting on the air with our creations is often secondary. This session will focus on QRP operating and making contacts. We will examine tips and tricks for success.
Jonathan Kayne KM4CFT The CFT1; the design philosophy and lessons in good user interface Jonathan Kayne is a 2021 graduate of Virginia Tech with a degree in Electrical Engineering, and is an avid POTA and SOTA activator. His presentation recounts the process and thoughts behind his newly popular QRP radio, the CFT1.
Jerry Weisskohl Learn CW like a boss My goal is to provide a proven method for rapid improvement in CW, focusing on a methodology that I have developed and successfully applied to become proficient in CW. The methodology is geared toward any CW operator with a working knowledge of the CW characters, with operating speed not being a critical factor for starting this program.
Thomas Witherspoon When the Grid Fails: A QRPer's Experience Post-Hurricane Helene When Hurricane Helene tore through western North Carolina in the fall of 2024, the damage was swift, unexpected, and widespread. In this photo-rich presentation, Thomas Witherspoon, K4SWL, will share his firsthand account of the storm’s aftermath and how amateur radio played a crucial role in staying connected when everything else failed. He will also offer practical advice for operators—no matter where they live—on how to prepare for natural disasters, build resilient communication setups, and foster stronger local networks. Even if you think you’re “out of harm’s way,” consider this your wake-up call to be ready.
Stewart Bryant Vibe(AI) Coding for the Radio Amateur Software is the new soldering iron and AI enables those less skilled in software to write working code. Examples are given of simple web apps, controlling relays and DDS systems, but at the end I give a few more advanced examples such as GNURadio and 3D modelling.
Jack Purdum Remote Magnetic Loop Antenna Tuner Magnetic loop antennas have numerous advantages in terms of size, but tuning them is tricky because the Q of a mag loop is very high, meaning a very narrow bandwidth. Many loops are tuned by listening to the audio level produced as the variable capacitor is varied. Body capacitance creeps in as you tune, causing some people to do a military crawl to sneak up on the loop as they tune it. This paper builds a remote tuner with SWR readout that takes the guesswork out of tuning. This inexpensive tuner also records the frequency/capacitor count so it can “learn” how to tune faster the more you use it.
Ross Ballantyne The development and construction of automatic antenna tuners for 640m, 2200m and 8900Hz operations Operating on the low bands of 630m, 2200m, Grimeton, 8900Hz and even the Schumann Resonance is quite difficult due to the enormous sizes of the antennas, inductors and capacitors required. This talk is the result of how to achieve the right components and make manual prototypes automated.
 
Additionally, we have scheduled Ashhar Farhan for a special presentation session at 7:00 PM Thursday, and Hans Summers for a special presentation session at 7:00 PM Friday. These evening sessions will be held in the Auditorium across from the Ballroom, and will be included in the Zoom Webinar package. Both Ashhar and Hans will have major announcements to make at these sessions, and you will NOT want to miss these!

FDIM 2026 Transmitter Challenge

 Among the many virtues which are embodied in the QRP radio hobby is that of economy. While the specific definition of QRP is operation at 5 watts or less, there is an unstated aesthetic which prefers the QRP radio do so with a certain minimalism in design, using as few components in its construction as possible, to be as economical as possible, and to operate with the highest efficiency possible.

While we have in past Design Challenges explored designs which have maximized power out from a few inexpensive amplifier devices, for 2026, we turn our attention to operating efficiency. We announce the 2026 FDIM QRP Transmitter Efficiency Challenge!

 1. The transmitter is to be operated from a fixed 12.0v power supply, and must demonstrate delivery of between 4.0 and 6.0 watts RF in the 40M band into a 50 ohm load.

2. The transmitter is to employ a 40M crystal as the frequency source.

3. A regulated 12.0 volt supply, 40M low-pass filter, dummy load, and power meter will be provided at the event.

 4. All circuit power is to be obtained from the 12.0v supply. No other power sources or energy storage may be used. Any cooling fans or other auxiliary circuits are to operate from this same 12v source, and their power consumption factored into overall efficiency.

 5. Output power from the 12.0v power supply will be calculated, and power into the dummy load measured. DC-to-RF efficiency will be calculated as the ratio of these two power numbers. The duration of the operational test will only be long enough to record power readings.

 6. There are no restrictions on the type of circuits, quantity or type of components, or class of amplifier that may be used, as long as the 40M crystal is the frequency source.

 7. Entries are to be checked in at the FDIM contest table by 8:30 PM on Friday May 15th during Club Night during the Four Days in May event.

 8. The circuit with the highest calculated DC-to-RF power efficiency will be declared the winner! Winners will be recognized at the FDIM Awards Dinner on May 16th.

 9. A schematic of the design is to be made available for review, and possible publication in QRP Quarterly magazine.

 

Good luck, happy designing, and see you in May!

73/72 Dave Cripe NM0S

 

QRP Hall of Fame - 2025

QRP-ARCI Announces Hall of Fame Induction - 2025

Dale Parfitt W4OP

QRPARCI is pleased to honor Dale Parfitt W4OP, with this induction into the QRP Hall of Fame.  Dale is a long time radio amateur, and the founder and president of PAR Electronics, a manufacturer and distributor of radio filters and antennas. Accepting this award on behalf of Dale was Jan N8CBX. 

Dale Parfitt W4OP - 2025 QRP Hall of Fame Inductee

Dave Cripe
NM0S
President QRP-ARCI

QRP Hall of Fame - 2025

QRP-ARCI Announces Hall of Fame Induction - 2025

Ron Potter AG1P (SK)

 

 

 

 

 

 

 

 

 

 

 

 

The votes have been tabulated, and QRPARCI is pleased to honor Ron Potter AG1P (SK) with this induction into the QRP Hall of Fame.  Ron was a long time QRP Amateur Radio Club International member and volunteer, as well as working with the 4 States QRP Group on many projects.  This award will reside with the Four States QRP Group as a memorial to Ron. 

Ron Potter AG1P - 2025 QRP Hall of Fame 

David Cripe
NM0S
President QRP-ARCI

QRP Amateur Radio Club International

QRP ARCI logo

QRP ARCI is a club for low power enthusiasts worldwide.

We produce a professional quality magazine (QRP Quarterly), organize an annual conference at Dayton ('Four Days In May' or FDIM), and sponsor various QRP contests and awards.

Our aim is to promote QRP and a variety of related activites. Many of our members enjoy home construction, kit building, antenna experimentation, backpacking and portable operation. Minimalist radios built in small tins are very popular but we also enjoy the very latest high performance radios such as the Elecraft KX3, the new SDR rigs, and great kits like the QCX from QRP Labs, kits from 4 States QRP Group, and the uBitx rigs. 

QRP-ARCI is an affiliated Club of the American Radio Relay League

Let us know if we can promote your club, group, kit or product.

New QRPARCI Mail List

qrparci.io

A new Mail List has been started for QRPARCI on the groups.io platform.  This mail list is open to members and non-members alike for the discussion of QRPARCI topics.  QRP-ARCI Staff handles the moderation of the list and you can gain access by sending an email to This email address is being protected from spambots. You need JavaScript enabled to view it. and requesting to be added  to the mail list.  Be sure to add your callsign in the request. You can get your mail in digest form as well if you prefer it that way.   73 de ARCI Staff Moderators

 

QRP Quarterly


 
QRP Quarterly - OCT 2025
 
Table of Contents - And More!  

Beyond the ’612—Jason Milldrum—NT7S

A Very Low Dropout Voltage Regulator—Don Cantrell—ND6T and Scott Schillereff—VE7SNJ

Exploring Common Mode Chokes—Brian R. Page—N4TRB

A Three-Element 20 Meter Vertical Beam—Carl Davis—W8WZ

Ham Sticks, Damn Sticks—Wayne Robertson—K4WK

Fair and Balanced: ATU Output Balance—Jerry Wolczanski—KI4IO

QRP on the Low Bands (Mainly 160M)—Gary Breed—K9AY

Ten Questions About Your QRP Operations—John Leonardelli—VE3IPS

A QRP Adventure in VE8—Jeff Hetherington—VE3CW

Review of the Xiegu G90—John Leonardelli—VE3IPS

SPOOLTENNA Review—John Leonardelli—VE3IPS

Field Day 2025—Jack Purdum—W8TEE

And much much more!

Sample of QRP QuarterlyTry it free !
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January 2015
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