Archive for the ‘Uncategorized’ Category

Amateur Radio Weekly – Issue 427

Amateur Radio Weekly

This weekend is Field Day
Field Day is Ham Radio’s open house.
ARRL

Field Day site locator
Find a Field Day event near you.
ARRL

LinHT Rev B status
What works, what broke, and why Rev C is next.
Zero Retries

Testing the new Tufteln Reel Antenna
The antenna is built directly into the reel itself.
QRPer

CQ Magazine archives
From its first issue in January 1945 up to present.
HamCall.net

World’s cheapest QRP antenna “tuner”?
A 6dB attenuator guarantees that the worst case SWR seen by the transmitter is no more than 1.67:1.
WB4SON

The contrast between old and new ways to communicate
A Mac Mini meets a Morse Code key.
Andrew Woodward

How to run AllStar on the Arduino UNO Q
The Arduino UNO Q is a compact, Qualcomm-powered single-board computer running full Debian Linux.
EtherHam

RFI found and removed
I noticed an offending signal on the Icom IC-7610 waterfall. The noise repeated approximately every 15 kHz.
VE9KK

OTA updates by drone
OTA updating hard to reach nRF52 based repeaters with a drone.
Meshcore.io

Video

Bringing 2m CW to the Quansheng
Enabling amazingly good Morse Code on affordable VHF/UHF radios.
SOTA+ and Brian Maybe Media

The final transmission of CHU shortwave radio
CHU shortwave went off the air on June 22, 2026 at 14:10 UTC.
Shortwave Listener

Testing antennas with NanoFarField Portable Antenna Lab
It took a bit of fiddling to set the thing up, and we had to find a big open field to use it, but this was a neat way to visualize antenna performance.
saveitforparts

Gangster 2m VHF antenna roof installation
Antenna installation how-to.
N7KOM

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Coast Guard Cutter Chelan: Biggest, Costliest Coast Guard Vessel of its Era

Take a step back in time to November 26, 1928, and take a look at what was then described as the biggest and costliest Coast Guard vessel of its era. The photograph shows the state of the art radio room aboard the U.S. Coast Guard Cutter Chelan. At the time this photo was taken, she was the newest cutter in the service, proudly anchored at the Navy Yard in Washington D.C.

Coast Guard Cutter Chelan

Constructed at a staggering cost of approximately $1,000,000 (1928 Dollars), the Chelan proved her incredible value right out of the gate. On her maiden trip, she picked up a desperate SOS signal and successfully towed a disabled schooner 1,500 miles to safety. This remarkable feat stood as a record tow for the service.

Chelan was laid down by Bethlehem Shipbuilding Corporation at Quincy, Massachusetts, on 14 November 1927 and launched on 19 May 1928. She was commissioned into U.S. Coast Guard service as USCGC Chelan on 5 November 1928.

Turbo-electric cutter, Lake-class (250-footers), built by Bethlehem Shipbuilding Corporation, Quincy, MA, at cost of $900,000 (hull & machinery), launched 19 May 1928, commissioned 5 September 1928, 2,075 tons displacement, 250ft long x 42ft beam x 12ft 11in draft, 17.5kts, armed with 1-5in/1-3in/2-6pdr (1929), 97 crew (1940).

Turbo-electric cutter, Lake-class (250-footers), built by Bethlehem Shipbuilding Corporation, Quincy, MA, at cost of $900,000 (hull & machinery), launched 19 May 1928, commissioned 5 September 1928, 2,075 tons displacement, 250ft long x 42ft beam x 12ft 11in draft, 17.5kts, armed with 1-5in/1-3in/2-6pdr (1929), 97 crew (1940).

The USCGC Chelan (WPG-45) was a 250-foot Lake-class cutter belonging to the United States Coast Guard, launched in 1928. Best known for its extensive operations in Alaska and a dramatic 1937 North Atlantic rescue, the ship was transferred to Great Britain during World War II.

Sitting at the operator station is Ensign Leslie B. Tollaksen. Tollaksen would go on to have a highly decorated military career, eventually serving as a Lieutenant Commander in World War II where he commanded a naval frigate, the USS Moberly, that helped sink a German submarine in the final days of the Atlantic naval war.

We see Tollacksen in the photo above as a fresh ensign aboard USCGC Chelan. From a genealogy page:

Tollaksen “attended the University of Washington for two years before going and graduating from the US Coast Guard Academy in New London, Connecticut. He graduated from The USCG Academy in the Class of 1927, a year early to man the ships chasing down rum runners.

As a young Lieutenant, he was assigned to the US Coast Guard HQ in Washington, DC. He helped establish “Radio Washington” the telegraph station on Telegraph Road in Washington, DC, and also served as Aid to the Secretary of the Treasury, Henry Morgenthau, Jr. (At that time, his sister worked in the typing pool for President Franklin D. Roosevelt’s White House).

Leslie Bliss Tollaksen (1903 – 1973), Also nown as,”Tolley”
Birthdate: April 13, 1903, Port Townsend, Jefferson County, Washington, United States. Death:1973 (69-70), Fort Lauderdale, Broward, Florida, United States

Leslie, about 1937 was the first US Coast Guard Officer selected for Post Graduate School at MIT.

Leslie, during WWII, and in command of the USS Moberly, sank the LAST German U-Boat U-853. U-8533 was a Type IXC/40 U-Boat, and lays on the bottom off Block Island…”

For history and technology buffs, the equipment in this radio room is absolutely fascinating. In 1928, maritime communication was undergoing a major technological revolution. Global maritime operations were beginning to phase out the older, notoriously noisy spark gap transmitters. Instead, the Chelan was outfitted with modern continuous wave vacuum tube technology. This room housed three powerful transmitters and three highly sensitive receiving sets.

If you look closely at the right side of the image, you can see the large glass vacuum tubes safely housed behind protective metal mesh doors. These power tubes allowed operators to transmit signals on specific, sharply tuned frequencies, reaching much further out to sea without causing interference for other ships. The tall black panels are also loaded with large rheostat dials for tuning, as well as precise ammeters and voltmeters to monitor the high voltages running through the system.

Meanwhile, Ensign Tollaksen has his hand positioned near a traditional straight telegraph key to send out Morse code. The receiver units he operated likely utilized regenerative or early superheterodyne circuits, giving operators the incredible sensitivity needed to hear faint SOS calls through heavy atmospheric static. It was exactly this kind of cutting edge machinery that allowed the crew to hear the distress call that led to their record breaking rescue!

USCGC Chelan was a Lake-class cutter belonging to the United States Coast Guard launched on 19 May 1928 and commissioned on 5 September 1928. After 13 years of service to the Coast Guard, she was transferred to the Royal Navy as part of the Lend-Lease Act, and named HMS Lulworth (Y60). During the war Lulworth served in a convoy Escort Group for Western Approaches Command. She returned to the U.S. Coast Guard after World War II.

USCGC Chelan was a Lake-class cutter belonging to the United States Coast Guard launched on 19 May 1928 and commissioned on 5 September 1928. After 13 years of service to the Coast Guard, she was transferred to the Royal Navy as part of the Lend-Lease Act, and named HMS Lulworth (Y60). During the war Lulworth served in a convoy Escort Group for Western Approaches Command. She returned to the U.S. Coast Guard after World War II.

Read more about this vessel: https://en.wikipedia.org/wiki/USCGC_Chelan.

GERMANY: USAGM Shortwave Operations Return to Lampertheim

Following the recent suspension of Voice of America (VOA) shortwave and medium-wave (AM) transmitters, the U.S. Agency for Global Media (USAGM) is orchestrating a gradual return to the airwaves.

Starting next week, USAGM will begin testing shortwave transmissions from the historic Lampertheim site in Hesse, Germany, which formerly served as a primary broadcasting node for Radio Free Europe and Radio Liberty (RFE/RL). This reactivation indicates that USAGM is working to restore its global broadcast capacity after surviving a period of severe operational cuts and the near-abandonment of its legacy transmission centers.

Lampertheim joins a growing list of international USAGM transmitting stations seeing renewed activity, including sites in Marathon (Florida), Greenville (North Carolina), Kuwait, the Philippines, Botswana, and Thailand. The permanent commissioning of these shortwave sites will depend heavily on the results of ongoing signal testing. The Lampertheim reactivation may ultimately serve as a temporary measure while USAGM awaits the completion of a major transmitter installation and upgrade project currently underway at the Kuwait Transmitting Station.

Built in the early 1950s during the height of the Cold War, the Lampertheim site was an RF (radio frequency) powerhouse, ruling the airwaves with eight massive 100 kW shortwave transmitters designed to pierce the Iron Curtain. Following the corporate merger of RFE and RL in 1976, the station broadcasted both services simultaneously. In 1995, under the newly formed Broadcasting Board of Governors (BBG–the predecessor to USAGM–the station became a consolidated hub for American international broadcasting.

The fall of the Soviet Union and the subsequent independence of Eastern European satellite states drastically altered the station’s mission. The target areas for Lampertheim’s massive curtain antennas were no longer geopolitical priorities, and direct shortwave programming was shrunk to almost nothing.

Instead, Lampertheim’s primary mission shifted toward technical, administrative, and logistical support. It became a vital satellite uplink and distribution gateway, beaming TV and radio programming to relay stations across Europe, Asia, and the Middle East. It also functioned as the remote-control nerve center for USAGM’s global network of transmitters, which included the medium-wave transmitter in Cape Greco, Cyprus (installed at the former RMC Middle East Transmitter Center), the strategic relay station in Djibouti, the massive 1,000 kW medium-wave transmitter in Orzu, Tajikistan, and, Technical oversight for nearly a hundred USAGM-affiliated FM transmitters globally.

During the wars in Afghanistan and Iraq, Lampertheim saw a brief resurgence in direct broadcasting as antennas were reconfigured to target the Persian Gulf and Southwest Asia, filling coverage gaps left by the Kuwait transmitters.

Today, radio enthusiasts and DXers can track the ongoing progress of USAGM’s shortwave broadcasts by consulting the HFCC A26 (Summer 2026) seasonal schedules here: HFCC A26 Schedule: https://new.hfcc.org/data/schedbybrc.php?seas=A26&broadc=AGM

Amateur Radio Weekly – Issue 426

Amateur Radio Weekly

The Remarkable, but Relatively Unsung Achievement of Integrating FreeDV RADE Into FlexRadio
FreeDV RADE is a voice mode that is more spectrally efficient than Single Sideband (SSB) and it’s more reliable than SSB.
Zero Retries

ITU corporation acquires Ameritron and Mirage RF amplifier
ITU acquires two additional premier Amateur Radio and communications brands from MFJ Enterprises.
Linton News

OscarWatch
OscarWatch shows where AMSAT spacecraft are, predicts passes over your station, works out Doppler-corrected uplink and downlink frequencies, and can drive your rotator and radio during a pass, all from one map-centred window.
MM9SQL

Amateur Radio’s role in my exchange year
I discovered how much I enjoyed traveling for Amateur Radio, learning about other cultures, and forming friendships with other young Hams from around the world.
OnAllBands

M9OMS VLDO V2
a discrete very low dropout (VLDO) linear voltage regulator for QRP radios. It delivers clean, RF-quiet power — selectable 9.0 V / 12.0 V / 13.8 V at up to 2 A — with strict voltage control and no switching noise.
M9OMS

What’s new at Digital Library of Amateur Radio & Communications
We’ve added 26 issues of FM Bulletin, which was a magazine chronicling early amateur FM on VHF/UHF, was published from 1967 to 1969.
Zero Retries

Recapping the 72 hours of E-skip palooza
It was a three-day symphony in the ionosphere over North America.
RadioWorld

Into The Mesh: Part 1
Like many things in Ham Radio, you can try to make a case that anything that doesn’t involve the internet would be good in an emergency.
KC8JC

The card that beat the sun
There are rare DXCC entities. And then there is Peter I Island.
KA3DRR

Meshyface
Meshyface is a chat-first Meshtastic dashboard that runs as a single Python service and serves a single-page web UI over HTTP.
jaronmcd

The most expensive piece of plastic… in the world
Repairing my Elecraft KX2 with the most expensive perspex on Earth.
EI3LH

Video

What is 44Net Connect?
Why you want to access this free system.
Ham Radio Crash Course

First Winlink email sent over Mercury on RF
The guys at Rhizomatica just made a better VARA than VARA. Unlike VARA, it’s free, open-source, and runs on Linux & Raspberry Pi.
KM6LYW

Low band HF DX: How it’s done
Discover the secrets behind low band HF antenna systems and how they can be used for DX operations.
TheSmokinApe Ham Radio

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Beyond the Sunspots: Understanding 10 Meter Propagation

I have noticed a common theme regarding propagation on the 10 meter band. There is a wide perception that when the band goes quiet and worldwide DX dries up in June or July, the solar cycle must be diving such that the frequencies become useless. Having written the propagation column in CQ Amateur Radio magazine since 2001, I have done much research into this topic.

The reality is that while the 11 year solar cycle certainly dictates overall band health, the dramatic differences we see between seasons on 10 meters are driven by complex changes in the Earth’s atmospheric chemistry and magnetic field.

The F2 Layer and the Winter Anomaly

During the autumn and spring months, 10 meters comes alive for long range global communication. To understand why this changes with the seasons, we have to look at the F2 layer of the ionosphere.

Complex Propagation Modes

The seasonal shift in thermospheric winds and the resulting chemical changes in the F2 layer are the true drivers of what we experience on the radio. This phenomenon is known in physics as the Winter Anomaly.

  • The Summer Fade: During the summer months, intense solar heating creates upwelling wind patterns in the thermosphere. These winds pull heavier molecular gases, specifically molecular nitrogen (N2) and molecular oxygen (O2), higher into the F2 region. This drastically increases the recombination rate of ions. The extra nitrogen acts like a sponge, rapidly absorbing the free electrons we need to reflect 28 MHz signals. Because the electron loss is so high, the overall electron density drops, and transoceanic skip fades away.

  • The Winter Peak: The opposite happens during the cooler seasons. As we move away from summer, the thermospheric winds shift and the heavy nitrogen settles back down. The F2 layer becomes dominated by atomic oxygen (O). Without the nitrogen there to absorb the electrons, the recombination rate slows down significantly. This allows a highly dense F2 layer to build up, reaching peak electron densities around November and February. This atomic oxygen rich environment creates the perfect reflective environment for global 10 meter communication.

Summer’s Silver Lining: Sporadic E

When summer arrives and the F2 layer thins out, the band brings its own unique conditions with the prevalence of Sporadic E propagation.

These intense, highly localized clouds of ionization form in the lower E layer of the ionosphere. Sporadic E provides incredibly strong short skip contacts. These openings typically range from a few hundred to a couple of thousand miles, temporarily replacing the global propagation we enjoy during the spring and fall. Most folks scrolling through social media just want a basic understanding of why they are suddenly making loud contacts into neighboring states instead of talking across the ocean, and Sporadic E is the answer.

Global Reach: TEP and Chordal Hop

For North American operators looking to communicate with places like Brazil or Australia, different propagation mechanics come into play.

For communication down into South America, you are dipping into a fascinating phenomenon called Transequatorial Propagation (TEP). TEP is deeply tied to the F2 layer conditions, but it is heavily driven by the structure of the Earth’s magnetic field near the equator.

Around the geomagnetic equator, the magnetic field lines run exactly parallel to the surface of the Earth. This causes the free electrons in the F2 layer to be pushed outward and downward, creating two massive, highly dense bands of ionization located about 15 to 20 degrees north and south of the magnetic equator. We call this the equatorial anomaly, and it is the engine for TEP.

When you transmit from North America down toward Brazil, your 10 meter signal hits that northern dense band. Instead of reflecting back down to the ground or ocean, the signal deflects horizontally across the equator high in the ionosphere. It then hits the southern dense band and reflects down into deep South America. Because the signal stays entirely in the upper atmosphere and avoids a lossy bounce off the Earth’s surface in the middle, the signals can be incredibly strong and clear. TEP is most reliable during the spring and autumn equinoxes, usually peaking in the late afternoon and early evening hours.

Talking to Australia from North America is slightly different because the path does not cross the magnetic equator at the perfect right angle needed for textbook TEP. However, working Australia often relies on a very similar principle called chordal hop propagation. Instead of bouncing between the ionosphere and the ocean all the way across the Pacific, the signal enters the F2 layer and skips along the underside of the ionosphere for thousands of miles. It stays trapped high up where there is very little absorption, eventually dropping down to receivers in Australia with surprising signal strength.

Regional Variances

Radio wave propagation is never a one size fits all experience. Your location on Earth plays a massive role in what you hear on 10 meters.

  • The Coasts versus the Midwest: If you live on the East Coast of the United States, your signals have a relatively unobstructed single hop path over the highly reflective saltwater of the Atlantic Ocean to reach Europe. The West Coast enjoys a similar geographic advantage when working Japan and the Pacific Rim. In the Midwest and central USA, your signals must often make an extra hop over land. Because land absorbs radio waves much more than saltwater does, central USA operators might find global F2 paths a bit more challenging. However, Midwest operators are perfectly positioned to work both coasts simultaneously when intense summer Sporadic E clouds form over the continent.

  • Equatorial Advantage: Operators located closer to the equator experience less of the severe Winter Anomaly shift. Because they sit under the equatorial anomaly, they enjoy much more consistent F2 and TEP openings year round compared to mid-latitude stations.

  • High Latitude Challenges: Operators in high northern or southern latitudes, such as Alaska or northern Europe, must contend with auroral absorption. During periods of high geomagnetic activity, the auroral oval expands and can severely degrade or completely absorb 10 meter signals, shutting down paths that cross the polar regions.

If 10 meters feels like a completely different band right now, do not blame the sunspot numbers. It is simply the natural seasonal shift in atmospheric chemistry and radio wave propagation at work. Enjoy the loud Sporadic E contacts while they last, and get ready for the worldwide skip to return when the seasons change.

Addendum: From the Southern Hemisphere

I was asked how this looks, from the land of Down Under.

Thank you for bringing the Southern Hemisphere perspective into the conversation! You hit the nail on the head regarding the inclination of the Earth’s axis, and it is the perfect starting point to explain why our experiences are mirrored.

Because the Earth is tilted on its axis by 23.5 degrees, the hemispheres take turns leaning toward the Sun as we orbit. Right now, the Northern Hemisphere is tilted toward the Sun, giving us summer. The Southern Hemisphere is tilted away, resulting in your winter. This means the ionospheric effects we experience are exactly reversed on the calendar.

When you mention that the high bands shut down after dark during your current winter, you are experiencing the harsh reality of wintertime solar geometry. During the winter months in the Southern Hemisphere, the Sun is much lower in the sky and the daylight hours are significantly shorter. While the Winter Anomaly we discussed earlier means your daytime F2 layer can actually become quite dense and highly supportive of 10 meter skip during the daylight hours, that ionization is entirely dependent on active sunlight. The moment the Sun sets at 5:30 PM, the source of ionization disappears. Because the winter night is so long, the F2 layer rapidly depletes, shutting the band down until the Sun rises again the next morning.

Conversely, when you head into your summer months of November and December, two major things happen. First, your daylight hours increase dramatically, which keeps the ionosphere charged much later into the evening and extends your operating time. Second, just as the Northern Hemisphere experiences a massive peak in Sporadic E propagation during our summer, the Southern Hemisphere experiences its own Sporadic E season during your summer. This provides those loud, reliable regional contacts. Finally, as you move into mid autumn around March and April, the Earth reaches the equinox. During the equinoxes, the Sun is directly over the equator, providing optimal and balanced F2 layer ionization for both hemispheres. This is why global, long haul propagation is at its absolute peak for everyone at the same time.

Regarding your question about East to West paths: yes, communication between Australia and South America is fundamentally very similar to the path between North America and Europe. Both are mid latitude transoceanic paths that rely on multi hop F2 propagation.

However, the Southern Hemisphere actually has a distinct geographic advantage for these contacts. Radio waves lose a small amount of energy every time they reflect off the Earth’s surface between ionospheric hops. Saltwater is an excellent, highly efficient reflector of radio waves, while landmasses absorb much more of the signal. Because the path between Australia and South America is almost entirely over the highly reflective saltwater of the Pacific Ocean, your multi hop signals suffer far less ground absorption compared to Northern Hemisphere paths that must often cross large expanses of land. This makes those Southern East to West paths incredibly efficient when the F2 layer is cooperating!

A Pileup? What It Is And How To Work One

Welcome to the chaotic, thrilling world of the HF pileup. Whether you are the one calling CQ from a park in Nebraska or the one hunting a rare DX station, success relies on rhythm, frequency management, and a deep understanding of human behavior.

Here is a proper look at how a pileup appears on a modern display, followed by a complete guide on how to survive it.

Temotu DXpedition (H40RH) pile-up, example waterfall.

A “pileup” on shortwave amateur radio frequencies. The main station is at the low frequency, and stays put. The hunters spread out, above, and call on a single frequency somewhere in the calling window of frequencies (I.e., up five to ten).

Over my decades of working Morse code (CW on amateur radio), I have learned a few critical things about how to navigate the chaotic, thrilling world of the HF pileup. When a rare station or a Parks On The Air (POTA) activator goes on the air, dozens or even hundreds of operators might try to make contact at the exact same time. Working a pileup is an art that takes time to master. Whether you are the one calling CQ from a park in Nebraska or the one hunting a rare DX station, success relies on rhythm, frequency management, and a deep understanding of human behavior.

One of the most important strategies is to determine the operating style of the DX station, specifically discerning how that operator scans the pileup for the next station to work. With modern waterfall displays, that process is MUCH easier. As an example, I worked the Temotu DXpedition (H40RH) that had just started a few hours prior to my attempt. I broke through with only five calls into the pileup, and it took me a mere 60 seconds to call and get an answer. Of course, I first listened and watched the waterfall for about five minutes to get a hang of the operating style of H40RH. This was on 10 Meters where 28.026 MHz was the DX frequency. We callers spread out five to 15 kHz UP in frequency from the DX station because we never want to cover up the DX station with our own signals. Even with a long carrier of intentional interference visible on the waterfall, the visual aid of the SDR made the catch possible. Temotu was a new country for my DXCC, so I am incredibly pleased to have made the contact!

When You Are the Hunted (The Activator)

A Guide To Survive The Pileup

When you are the station that everyone wants in their logbook, you are the conductor of the orchestra. If the pileup senses hesitation, chaos ensues. You must dictate the pace, for both CW and SSB operations.

Controlling the Pileup on CW

Establish a Predictable Rhythm: Your CQ, your exchange, and your QRZ should follow a strict pattern. Consistency allows hunters to time their calls perfectly. If you change your cadence, the pileup gets messy.

Run Split for Large Piles: If the pileup merges into a single continuous drone, go split immediately. You might send “UP 1” to tell callers to transmit one kilohertz above your listening frequency. This spreads the callers out. Send your “UP” frequently enough that the self-appointed pileup police do not take over your transmit frequency. I suggest sending “UP” after each successful logged contact (QSO).

Own the Partials: If you only pull “NW7” out of the noise, send “NW7?”. Do not send “QRZ?” immediately. Stick to that partial call until that specific station finishes the exchange. If they fade out, clearly send “QRZ?” to reset the pile.

Adjust Speed to Control Volume: A slight speed increase (bumping up 3 to 5 WPM) will naturally thin the pileup down to the more experienced operators. Dropping your speed will invite the newer operators back in.

Receiver Management: Back off your RF gain and use a wider filter than you might expect (around 400 to 500 Hz). A filter that is too narrow will cause you to miss the operators who are smartly calling slightly off-frequency.

Controlling the Pileup on SSB

Command with Your Voice: Speak clearly and maintain a steady, authoritative tone. Avoid shouting. Just like in CW, a predictable rhythm helps callers know exactly when to key their microphones.

Use Standard Phonetics: Stick strictly to the standard NATO phonetic alphabet (Alpha, Bravo, Charlie). Cute or custom phonetics confuse operators who do not speak English as their first language.

Acknowledge and Isolate: When multiple voices blur together, listen for the last phonetic letter you can understand. If you hear “Sierra,” say “The station ending in Sierra, go ahead.” Ignore everyone else until that station completes the contact.

My POTA / Portable HF station (a low-power, or, QRP, station).

My POTA / Portable HF station (a low-power, or, QRP, station).

When You Are the Hunter (The Chaser)

When you are trying to break through a massive wall of sound, raw output power is secondary to timing and sharp observation.

Breaking the Pileup on CW

Listen First, Key Second: Before touching the paddle, listen to three or four complete exchanges. If the activator is working split, figure out their pattern. Are they tuning from the bottom up? Top down? Find where they listened last, and place your transmit frequency just above it.

Use XIT (The Golden Rule): Never perfectly zero-beat the DX station if others are calling. To the activator, three zero-beat stations merge into a single tone. Use your Transmitter Incremental Tuning (XIT) to shift your transmit frequency by 30 to 50 Hz. This slight difference in pitch makes your signal pop out of the receiver passband.

Time the Tail-End: Wait for the massive wall of sound to begin fading, and send your call exactly as the main group finishes. A perfectly timed tail-end call lets your suffix ring out in the clear.

Send Once: When the DX sends “QRZ?”, send your callsign exactly once and listen. Sending your call multiple times just causes interference and slows down the entire operation.

Follow Instructions: If the DX sends “NW7?”, and that is not you, keep your hand off the key. Transmitting over the station they are trying to work only prolongs the pileup for everyone.

Breaking the Pileup on SSB

Study the Cadence: Just like with Morse code, listen to the activator to find the rhythm. Wait for the exact moment the activator stops speaking before you key up.

Drop Your Call and Wait: Say your full callsign once using standard phonetics, then unkey and listen. If you are tail-ending, you might just drop the last two letters of your callsign precisely as the noise floor drops.

Adjust Your Pitch: If you have equalization controls on your radio, boost the mid-to-high frequencies on your microphone audio. A slightly punchy and higher-pitched voice will cut through the bass-heavy rumble of a dozen other stations calling at once.

Working a pileup tests your patience and your ear. Whether you are tapping out Morse code or speaking into a microphone, the operator who listens more than they transmit almost always makes the contact first.

Propagation and the Pile-Up

As many of you know, I was the space weather and radio propagation columnist in CQ Amateur Radio Magazine from 2001 through its demise. I strongly advocate for all HF radio operators to understand the basics of radio wave propagation on shortwave frequencies. There are a lot of myths and frankly, horrific theories on how radio waves propagate.

Understanding how the ionosphere refracts radio waves is a crucial tactical advantage. The behavior of a pile-up changes dramatically based on the frequency band you choose and the current mood of our sun.

The Sun Dictates the Rules

The ionosphere is charged by solar radiation. When solar activity is high, higher frequencies become usable for long distances.

Solar Flux Index: The SFI is a great indicator of overall ionization. A higher SFI means better conditions for the higher HF bands. When the SFI climbs, bands like 15, 12, and 10 meters open up globally.

Geomagnetic Storms: Measured by the K-index, these storms can disrupt communications entirely. A high K-index often absorbs signals crossing the polar regions. This can suddenly mute a massive European pile-up for North American operators.

Fading: The ionosphere is always shifting. Signals will constantly rise and fall in strength, which is known as QSB. A smart chaser listens for the rhythm of this fade and throws their callsign into the pile-up exactly when the band peaks for their specific location.

How Bands Shape the Pile-Up

Every amateur radio band has its own personality. The pile-ups you encounter will reflect these differences perfectly.

10, 12, and 15 Meters: These high bands are daytime frequencies that thrive on high solar activity. When 10 meters opens up, signals can be astonishingly loud with very low atmospheric noise. Pile-ups here can ignite suddenly and stretch very wide across the frequency spectrum.

20 Meters: This is the traditional workhorse band for global communication. Pile-ups on 20 meters are massive, sustained, and densely packed. You will often compete with high-power stations and massive beam antennas on this frequency day or night.

40 and 80 Meters: These low bands come alive at night. They are heavily affected by atmospheric noise and static crashes. Breaking a pile-up here requires an exceptionally well-tuned ear and the ability to pull faint CW tones or muffled voices out of a very high noise floor.

The Skip Zone Effect

The propagation of radio waves.

The propagation of radio waves.

One of the most confusing aspects of a pile-up for a new operator is the skip zone. Radio waves bounce off the ionosphere and return to earth far away, which means they skip right over the geographic areas in between. You might hear the DX station perfectly, but you might not hear the hundreds of other operators calling them because those callers are inside your skip zone. This phenomenon is exactly why you must rely on the DX station’s cadence rather than waiting to hear the pile-up clear.

While raw power is often cited as the key to breaking a pile-up, your antenna system plays a far more decisive role in your overall effectiveness. A directional antenna, like a Yagi or a hexbeam, not only focuses your transmitted energy directly toward the DX station but also actively rejects interfering signals from other directions. However, do not be discouraged if you are running a simple wire antenna. A well-placed dipole or end-fed half-wave can still break monumental pile-ups if you leverage good timing, exploit the skip zone, and listen closely to the DX operator. Ultimately, the best antenna in the world cannot compensate for poor operating habits.

Over to You

Working a pile-up is one of the most rewarding challenges in amateur radio. It tests your patience, refines your ear, and forces you to understand both the science of radio wave propagation and the psychology of your fellow operators. Every massive wall of sound is a puzzle waiting to be solved.

Now, I would love to hear from you. What was your most memorable pile-up experience? Do you have a specific tactic that consistently helps you break through the noise, or perhaps a frustrating moment that taught you a valuable lesson? Drop your stories and questions in the comments below, and let us keep the conversation going.

From my shack to yours, 73 de NW7US.

Amateur Radio Weekly – Issue 425

Amateur Radio Weekly

Hamilton Auto FT8
Hear, call, exchange, complete, log — automatically.
Hamilton

QSO One
Connect to AllStarLink and EchoLink from Windows or Android — no hardware, no soldering, no sysop headaches. More platforms coming soon.
QSO One

The Machine Learns to Listen
The machine was doing something beyond my capability. It wasn’t just assisting me. It wasn’t automating something I could do manually if I had the patience. It was actually exceeding my physical capabilities.
EtherHam

Things On The Air (TOTA)
For TOTA to achieve the vision of being the “last list of things on the air”, it must accommodate an unlimited number of listed things.
K0NR

Amateur Radio magazines
This is a living list of in-production print and digital magazines related to Amateur Radio from around the world.
K3LOE

Powerline QRM monitor
A tool for Ham Radio operators to continuously monitor, log, and publish measurements of powerline interference (QRM).
N6OL

Mirror Yagi – Unconventional reversing
For productive paths that are 180° apart, reversible wire yagis can be very effective.
Pattern and Match

Non announcements from Icom
ID-5200 to come in two models and it’s still awaiting FCC approval.
Andrew Woodward

Ask an Astronaut
Find questions among hundreds of astronaut interviews aboard the ISS. Search for “ham radio.”
ISS In Real Time

1976 U.S. Bicentennial callsigns
In 1976, Amateur Radio operators in the United States were allowed the option of using a special prefix in place of their regular callsign.
The SWLing Post

The empty field that wasn’t
What 12 million GPS special messages reveal about military rekeying on a public channel.
InsideGNSS

Video

M17 on iOS MSEVEN on Mobilinkd TNC4
Transmitting M17 digital voice signals over the air.
A5ME

MeshCore tips FAQ
Everything you need to know to get the most out of your MeshCore network.
The Comms Channel

$2,500 bought us insane coverage
We installed a brand new G2Station MeshCore repeater on top of Short Mountain, the highest point in Middle Tennessee, and the results speak for themselves.
KM4ACK

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  • Matt W1MST, Managing Editor