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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.

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).

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.

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.

Curious about what you can hear on shortwave ham radio? This video is a brief survey of the diverse world of communications on the shortwave spectrum. Expand your radio horizons and enhance your emergency communication preparedness by tuning in to the world of shortwave ham radio.

If you’ve started delving into radio communications beyond local stations and channels, like VHF and UHF, you’re in for a treat. Shortwave radio opens up a whole new realm of signals to explore, including emergency communications vital during natural disasters.

[embedyt] https://www.youtube.com/watch?v=pIVesUzNP2U[/embedyt]

Shortwave radio covers a range of radio frequencies from 3 kHz to 30 MHz. This spectrum is home to a diverse array of radio signals that cater to various communication needs, making it a hub of activity and connectivity.

Within these high frequencies, you can tune in to a multitude of transmissions, from transoceanic air traffic control communications to the chatter of ships navigating the vast seas. Imagine hearing the voices of fishermen, much like those on your favorite reality TV shows about high-seas fishing adventures, along with military communications and the vibrant world of amateur radio enthusiasts.

One of the remarkable features of high-frequency (HF) radio is its ability to propagate signals over long distances, transcending line-of-sight limitations. This means that HF radio enables communication between different regions and even continents, fostering connectivity across vast distances.

During times of crisis and natural disasters, shortwave frequencies become invaluable for emergency communications. When local infrastructure falters or is disrupted, shortwave radio serves as a vital lifeline, facilitating critical two-way communications in and out of disaster-stricken areas.

Explore the fascinating realm of shortwave radio, where distant voices blend with essential information, bridging gaps and connecting communities in times of need. Uncover the power of HF radio to transcend boundaries and provide lifelines when they are needed most.

In this video, I give you a glimpse of the voice and data transmissions I pick up on my high-frequency amateur radio transceiver (in this video, an Icom IC-7000). In later videos, I will dive deeper into specific types of HF communications, such as aeronautical trans-oceanic signals.

Turning back time to virtually witness a critical historic method of shortwave communication using the fundamental mode of continuous wave modulation. This is a film from 1944, teaching the basics of Morse code, for military comms.

What is the proper (and most efficient) technique for creating Morse code by hand, using a manual Morse code key? Ham radio operators find Morse code (and the ‘CW’ mode, or ‘Continuous Wave’ keying mode) very useful, even though Morse code is no longer required as part of the licensing process. Morse code is highly effective in weak-signal radio work. And, preppers love Morse code because it is the most efficient way to communicate when there is a major disaster that could wipe out the communications infrastructure.

[embedyt] https://www.youtube.com/watch?v=qmg1MlstxWM[/embedyt]

While this military film is antique, the vintage information is timeless, as the material is applicable to Morse code, even today.

Credits: National Archives and Records Administration

Department of Defense. Department of the Army. Office of the Chief Signal Officer. (09/18/1947 – 02/28/1964)

ARC Identifier 36813 / Local Identifier 111-TF-3697. PRINCIPLES AND BASIC TECHNIQUE FOR GOOD, RHYTHMIC SENDING 0F MORSE CODE BY OPERATING THE HAND KEY.

Made possible by a donation from Mary Neff.

Before modern radio broadcasting, the trails were being blazed both in public broadcast, but also critical links out of the local area. Here’s a side-look back in time…. in this 1939 Film: New Zealand Shortwave Communications; Morse code (CW)

The romance of the radiotelegraph service (in this video, the service in New Zealand) is a fascinating aspect of communication history. The use of shortwave, longwave, and medium frequency spectrum for communication, particularly through Morse code, played a significant role in connecting people across vast distances. This service utilized the high-frequency spectrum known as “shortwave” (from 3 MHz up to 30 MHz) as well as the longwave (30 kHz to 300 kHz) and medium frequency spectrum (300 kHz to 3 MHz).

This short film is from 1939, and captures the essence of communication at that time in history, to and from New Zealand using shortwaves and Morse code. It showcases the importance of the radiotelegraph service in enabling long-distance communication during that era. The transition from Morse code via spark-gap communications to continuous wave (CW) modulation marked a significant advancement in the technology and efficiency of radio communication.

It’s incredible to see how technology has evolved over the years, transforming the way we communicate and connect with each other globally. Films like these provide a glimpse into the past and remind us of the ingenuity and dedication of those who worked in the radiotelegraph service to ensure effective communication across the seas.

[embedyt] https://www.youtube.com/watch?v=H-KUat5WEkU[/embedyt]

This film is a 1939 Government film scanned to 2K from a 16mm combined B/W reduction print.

If you have not yet explored ham radio repeaters, this might be interesting to you.

What is an amateur radio repeater and how do they work?

In this video, with a non-amateur-radio viewer in mind, I chat about the very basic concepts of a repeater.

It is filmed in a relaxed, “ride along with me,” format.

Want to learn more about ham radio (amateur radio)?
Visit: http://nw7us.us/arrl

[embedyt] https://www.youtube.com/watch?v=R_a5Pxh931U[/embedyt]

I had so many plans for my Hamvention 2023 visit on Friday and Saturday, May 19-20, 2023.  For example, I planned on many interviews including one with N3ZN, maker of great Morse code keys.  I also needed to visit the Card Checker Service of the ARRL DXCC program.  I had a handful of DX cards I was submitting toward DXCC credits.

NW7US, in ICU at the hospital, instead of attending Hamvention 2023.

But, I collapsed about 40 minutes after I got to the Hamvention, on Friday morning! I had just finished getting my DX QSL cards checked at the ARRL booth, then I collapsed. After only being at my first Hamvention for a brief 40-some minutes, I was taken by ambulance to an ER of a Xenia-area hospital.  My blood pressure was difficult to measure at the initial moments of being at the emergency room — it was about 60 over 40, and I had NO radial pulse.

After a CT scan of heart and neck, and blood lab work, I was transported again by ambulance to a hospital near Dayton. There, I was admitted to that hospital’s Intensive Care Unit (ICU) around 5:30 PM on Friday.

I’m writing this on Saturday, from my hospital bed, as I’m still in ICU in Dayton. I hope to be discharged tomorrow (Sunday, 21 May 2023).

The working diagnosis is Acute Kidney Injury (AKI), caused by a combination of issues starting with my parathyroidectomy surgery, a few months back. I had three of my four parathyroid glands removed because they were completely tumorous.  I wrote about that in my previous entry on this website.

Turns out my calcium levels were lower than they should be, causing problems throughout my body, but especially in my heart. Additionally, I was severally dehydrated due to two medications I had been taking because the VA doctors thought I should be on them.  But, these meds were working against me. One of those I don’t even need, but the VA had me taking. That one is FUROSEMIDE. The other is LISINOPRIL.  I don’t have high blood pressure, nor water retention.

At the ICU, I have stopped taking those meds.  I’m on an IV, getting hydrated, and getting calcium supplements.

My kidney function is improving but I’m going to spend another night in ICU until they feel confident I’ve made full recovery.  I hope to be discharged on Sunday, 21 May, 2023.

I hope all of you that were at this year’s Hamvention have enjoyed the fellowship of radio enthusiasts. Maybe I’ll meet many of you, next year!  I will make videos of Hamvention 2024, if all goes well in a year’s time.

If you were at Hamvention 2023, share some highlights in the comments!

UPDATE:  On Sunday, I was released from the ICU, and I am now home recuperating.  Monday is a bit rough, so am not at work, yet.  BP is normal, and I am on new medication for my heart so that I do not get dehydrated by the furosemide and lisinopril.  Here’s hoping for next year’s Hamvention, which I hope to attend.

73 de NW7US
https://nw7us.us
..

The last three years have been, well, challenging.

In 2021, I became ill with Covid.  That was rough, but I bounced back.  That bout with illness caused me to lose my job, though, because I was ill too long.  What is worse is because I was not hospitalized, I did not fall under the protections of “disability,” and had to step down from my employment at that time.  After I recovered, I found employment.

In 2022, I again fell ill to a second Covid.  That illness was significantly worse!  I nearly WAS hospitalized, but I resisted this, and hung on by a thread. I made it through, though the illness lasted a lot longer the second time around. Because I was ill for about five months, I again had to step down from employment.  This second Covid was the worst illness I have ever experienced, physically, emotionally, and financially.  I am thankful for my friends and family that were very supportive.

After I recovered, I found employment in late 2022.  It took a while for my health to stabilize, but the new job leadership has been supportive.  I have been happily working at this new job since late 2022.

But, the challenge to recover was high.  I sought answers.

In December 2022, I was diagnosed with Primary Hyperparathyroidism.  Sure enough, the many tests I endured confirmed that I had more than one tumor in at least two of my four parathyroid glands (we each have four of them, because we’re given redundancy for this critical body part).

We each have four parathyroid glands. They are on the back side of the thyroid. The regulate the body’s calcium. Calcium is critical to all body functions and health.

I had surgery at the end of February 2023 to remove these tumor-riddled glands.  The surgeon, once in my neck, found that THREE of my four glands were tumorous!  He removed the three.  I now have just one parathyroid gland.

Recovery has gone well.  My health is improving nicely.  It is like a switch was flipped, and I no longer have some of the debilitating symptoms like brain fog, extreme fatigue, and an out-of-control metabolism.  I have a stable function of the remaining parathyroid gland, and that is supporting the proper function of the rest of my body.  It is amazing how the whole body relies on these four glands for running correctly!

All of these challenges of the last few years caused enough distraction that my YouTube channel, and my writing, here, as well as other hobby activities, suffered my absence.  Now that I am getting back on my feet with my health, and because my job continues nicely, I am beginning to spend some energy and time on these hobby areas.  I plan on creating and releasing a few series on amateur radio, radio propagation, and space weather, on my YouTube channel.  If you are already a subscriber, you probably saw my latest video where I announce that I am, indeed, back:

[embedyt] https://www.youtube.com/watch?v=vhL8CKbLkZY[/embedyt]

If there are topics that you would like me to cover in the new educational videos I am planning and will create, please let me know with a comment to this post, or, look my email address up on my profile at QRZdotCom.  I will do my best to answer your questions and cover amateur radio and space weather topics in which you are interested.

If you are not yet familiar with my YouTube channel, you can find my channel here:  https://YouTube.com/NW7US — Please subscribe and hit the bell to be notified when I release new video content.

I will also post more often on this site.  I appreciate the opportunity to share with you my love of amateur radio, and the science of propagation and space weather which affects our radio signals.

Best regards,

Tomas, NW7US
https://NW7US.us