When the Weather Forecast Predicts Great VHF Conditions
21/07/26 10:39
By Greg Lewis, N5XO
Last week, every weather forecast across Texas and much of the South was talking about one thing—a massive heat dome settling over the region.
As soon as I saw those forecasts, I posted several messages on Facebook and in our HAMster Weak Signal Group telling everyone to get ready. I explained that this week had all the ingredients for outstanding VHF and UHF propagation, and that operators should expect enhanced simplex and weak-signal conditions.
Yesterday and today, those predictions proved to be right on the money.
Not only have I personally been making contacts right and left, but many of my fellow HAMsters have been doing exactly the same thing. We've been working stations on both 2-meter FM simplex and 2-meter SSB into Louisiana, Arkansas, and hundreds of miles across Texas—contacts that simply aren't possible under average band conditions.
Stations that normally struggle to hear one another have suddenly been exchanging strong signals. Operators who are accustomed to local coverage have found themselves working entirely new areas with ease.
Since then, I've received numerous emails and text messages asking the same question:
"Greg...how did you know this was going to happen?"
The answer is actually pretty simple.
It Wasn't a Guess
This wasn't luck.
It wasn't wishful thinking.
And it certainly wasn't a crystal ball.
It was simply understanding how weather affects radio propagation.
Whenever meteorologists begin talking about a large, persistent high-pressure system or "heat dome" during the summer, my attention immediately shifts from the weather forecast to the propagation forecast.
Over the years, I've learned that when the atmosphere begins setting up in a certain way, the VHF bands often respond in spectacular fashion.
What Is a Heat Dome?
A heat dome is a massive area of high atmospheric pressure.
Instead of allowing warm air to rise and mix with cooler air above it, the high-pressure system compresses the atmosphere and traps the hot air near the surface.
That creates:
- Very hot temperatures
- Light winds
- Stable atmospheric conditions
- Little vertical mixing of the air
- Clear skies for days at a time
Weak-signal operators hear something entirely different.
We hear...
Potential tropospheric enhancement.
The Atmosphere Becomes Layered
Normally, the atmosphere is constantly mixing.
Warm air rises.
Cool air sinks.
Humidity changes.
Everything is fairly turbulent.
Under a strong heat dome, however, the atmosphere becomes extremely stable.
Layers of air with different temperatures and humidity begin stacking on top of one another.
These layers change the way radio waves travel through the atmosphere by altering its refractive index.
Instead of traveling straight into space, VHF and UHF signals begin bending slightly, allowing them to follow the Earth's curvature much farther than they normally would.
Temperature Inversions
One of the biggest contributors is something called a temperature inversion.
Normally, temperatures decrease as altitude increases.
During an inversion, warmer air sits above cooler air near the ground.
That boundary acts almost like an invisible waveguide for VHF and UHF signals.
Instead of escaping upward, signals become trapped between atmospheric layers and can travel hundreds of miles.
This phenomenon is known as tropospheric ducting, and while this week's conditions haven't necessarily been full-blown ducting everywhere, they have certainly produced excellent tropospheric enhancement across much of Texas and neighboring states.
What We've Been Experiencing
The past two days have been a perfect example of why understanding weather patterns is so valuable to VHF operators.
Across the HAMster group we've been hearing reports of:
- Outstanding 2-meter FM simplex contacts.
- Long-distance 2-meter SSB QSOs.
- Stations working into Louisiana and Arkansas.
- Hundreds of miles of coverage across Texas.
- Signals that sound more like local contacts than distant stations.
- Strong, stable copy that lasts for extended periods.
Why Weather Forecasts Matter
Many amateur operators watch solar reports or DX clusters.
Weak-signal VHF operators should also become students of the weather.
Whenever forecasts begin mentioning:
- Heat Domes
- Strong High Pressure
- Persistent Upper-Level Ridges
- Calm Winds
- Clear Skies
- High Humidity
Those weather patterns frequently create the stable atmosphere needed for enhanced VHF and UHF propagation.
Learn to Read More Than the Radio
One of the best propagation tools available isn't expensive software or a fancy receiver.
It's your local weather forecast.
After years of chasing weak signals, you begin recognizing atmospheric patterns that repeatedly produce enhanced propagation.
The atmosphere leaves clues.
Meteorologists simply describe them.
Once you know what to look for, you can often predict outstanding operating conditions several days before they arrive.
That's exactly what happened this week.
The Takeaway
This week's excellent conditions weren't a surprise.
They were simply the atmosphere behaving exactly as physics says it should.
Watching fellow HAMsters take advantage of the conditions has been every bit as enjoyable as making the contacts myself. Seeing operators work stations hundreds of miles away on both FM simplex and SSB is a great reminder that VHF is capable of far more than many people realize.
The next time your television meteorologist starts talking about a heat dome settling over Texas...
Don't just think about how hot it's going to be.
Think about turning on the radio.
The atmosphere may be opening a highway across the sky.
73,
Greg Lewis, N5XO Founder, HAMster Weak Signal Group
Simplex Is Not the Problem… It's the Solution
12/07/26 06:16
Why Simplex and Weak Signal Operating Still Matter
By Greg Lewis, N5XO
Over the past several years I've heard the same comment repeated more times than I can count.
"Simplex nets are a bad idea."
Usually that opinion comes from someone who simply cannot participate effectively on simplex because their station, antenna system, or operating location doesn't allow it. The conclusion they reach is that all nets belong on repeatersbecause "that's where everyone can hear everyone."
I respectfully disagree.
In fact, I believe that mindset runs contrary to one of the very foundations upon which Amateur Radio was built.
Let's Define the Difference
Before we go any further, let's make sure we're talking about the same thing.
A Simplex Net
A simplex net operates with every station transmitting and receiving on the same frequency, with no repeater or outside infrastructure involved.
Every signal you hear is traveling directly from one station to another.
Your success depends upon:
Your station.
A Weak Signal Net
A Weak Signal Net is a specialized form of simplex operation.
Instead of simply trying to communicate locally, operators intentionally push the limits of their stations to make contacts at remarkable distances using modes such as:
They're looking for the contact everyone else thinks can't be made.
That's experimentation.
That's engineering.
That's Amateur Radio.
Repeaters Are Wonderful...
Let's be perfectly clear.
I own repeaters.
I appreciate repeaters.
Repeaters serve an incredibly valuable purpose.
They allow handheld operators to communicate over large areas.
They support emergency coordination.
They provide daily conversation and fellowship.
They introduce countless newcomers to our hobby.
Repeaters absolutely have their place.
But...
They should never become a crutch.
What Happens When the Repeater Isn't There?
This is the question every Amateur Radio operator should honestly ask themselves.
What happens when:
If your entire Amateur Radio experience depends upon talking through a repeater...
...your communications capability just disappeared.
The operator who regularly practices simplex doesn't have that problem.
Neither does the Weak Signal operator.
They're already accustomed to communicating directly.
Exactly the way Amateur Radio was originally designed.
Emergency Communications Begins With Direct Communications
One of the stated purposes of Amateur Radio is providing emergency communications.
Notice what it doesn't say.
It doesn't say:
"Emergency communications...provided the repeater is still working."
Infrastructure is wonderful...
until it isn't.
History has shown us repeatedly that hurricanes, tornadoes, floods, ice storms, wildfires, and other disasters don't always leave infrastructure standing.
The operator who has learned how to communicate directly station-to-station possesses a skill that cannot be replaced by a taller tower or a more elaborate repeater system.
Amateur Radio Has Always Been About Pushing Limits
One of my favorite things about this hobby is that hams have spent over a century proving people wrong.
How many times have we heard...
"That band is useless."
"Those frequencies are garbage."
"You'll never communicate very far on that."
We've heard it over...
and over...
and over.
Then hams went out and did exactly that.
Six meters?
Called "The Magic Band."
Two Meter SSB?
Hundreds of miles.
432 MHz?
Hundreds of miles.
1296 MHz?
Hundreds of miles.
Microwave?
Thousands of successful contacts.
Moonbounce?
Signals literally traveling nearly half a million miles.
Every generation of Amateur Radio operators has expanded what people believed was possible.
Not by accepting limitations...
But by challenging them.
Our Nets Are Proving the Point
Here in South Texas, our Simplex and Weak Signal Nets continue demonstrating exactly why these activities matter.
Week after week we hear stations checking in from distances that surprise many operators.
Some are using modest stations.
Others have invested in improving antennas, feedlines, mast height, low-noise preamps, or operating techniques.
Many of those improvements happened because someone listened during a net and thought:
"If they can do it...maybe I can too."
That's exactly the kind of inspiration our hobby needs.
I've watched operators upgrade from:
Each improvement expanded their capabilities.
Each improvement made them a better operator.
No repeater could have taught those lessons.
Don't Lower the Standard...
Raise Your Station
If simplex is difficult...
don't give up.
Improve your station.
Raise the antenna.
Replace poor coax.
Experiment with antenna designs.
Learn about feedline loss.
Study propagation.
Try horizontal polarization.
Optimize your equipment.
Ask questions.
Learn from operators who have already traveled that road.
The answer isn't to abandon simplex.
The answer is to become better at simplex.
That journey is where Amateur Radio becomes truly rewarding.
The Culture We Should Encourage
Instead of saying:
"Simplex doesn't work."
Let's ask:
"How can we make it work better?"
Instead of saying:
"You need a repeater."
Let's ask:
"How can we improve your station so you don't?"
That subtle difference changes everything.
One accepts limitations.
The other overcomes them.
The Spirit of Amateur Radio
At its heart, Amateur Radio has never been about taking the easiest path.
It's about learning.
Experimenting.
Building.
Improving.
Teaching.
Mentoring.
Sharing.
Discovering.
If every contact is made through infrastructure built by someone else...
we miss one of the greatest educational opportunities this hobby offers.
Simplex reminds us that our station matters.
Weak Signal reminds us that our imagination matters.
My Challenge
If you've never joined a Simplex Net...
Give it a try.
If you've never operated 2 Meter SSB...
Borrow a radio.
Listen.
Ask questions.
If your station isn't reaching as far as you'd like...
Don't become discouraged.
Become curious.
Every antenna improvement teaches something.
Every foot of added height matters.
Every better connector, every lower-loss feedline, every improved operating technique moves you one step farther down the road.
You may surprise yourself.
And one evening you'll hear a distant station answer your call—a station you never imagined you could work.
That moment is what Amateur Radio is all about.
Not because a repeater connected you.
But because you connected.
That is the spirit of Amateur Radio.
That is why we continue promoting Simplex and Weak Signal operation.
Not because repeaters are unimportant.
But because Amateur Radio has always belonged to those willing to discover what lies just beyond the horizon.
And history has shown, time and time again...
Those horizons are always farther away than we first believed.
73,
Greg Lewis – N5XO Founder, HAMster Weak Signal Group Emergency Coordinator – Bandera County ARES
By Greg Lewis, N5XO
Over the past several years I've heard the same comment repeated more times than I can count.
"Simplex nets are a bad idea."
Usually that opinion comes from someone who simply cannot participate effectively on simplex because their station, antenna system, or operating location doesn't allow it. The conclusion they reach is that all nets belong on repeatersbecause "that's where everyone can hear everyone."
I respectfully disagree.
In fact, I believe that mindset runs contrary to one of the very foundations upon which Amateur Radio was built.
Let's Define the Difference
Before we go any further, let's make sure we're talking about the same thing.
A Simplex Net
A simplex net operates with every station transmitting and receiving on the same frequency, with no repeater or outside infrastructure involved.
Every signal you hear is traveling directly from one station to another.
Your success depends upon:
- Your antenna
- Your feedline
- Your radio
- Your operating technique
- Your location
- Your understanding of propagation
Your station.
A Weak Signal Net
A Weak Signal Net is a specialized form of simplex operation.
Instead of simply trying to communicate locally, operators intentionally push the limits of their stations to make contacts at remarkable distances using modes such as:
- 2 Meter SSB
- 70 cm SSB
- CW
- Digital modes
- Tropospheric enhancement
- Meteor Scatter
- EME (Earth-Moon-Earth)
- Microwave bands
They're looking for the contact everyone else thinks can't be made.
That's experimentation.
That's engineering.
That's Amateur Radio.
Repeaters Are Wonderful...
Let's be perfectly clear.
I own repeaters.
I appreciate repeaters.
Repeaters serve an incredibly valuable purpose.
They allow handheld operators to communicate over large areas.
They support emergency coordination.
They provide daily conversation and fellowship.
They introduce countless newcomers to our hobby.
Repeaters absolutely have their place.
But...
They should never become a crutch.
What Happens When the Repeater Isn't There?
This is the question every Amateur Radio operator should honestly ask themselves.
What happens when:
- Commercial power fails?
- The backup battery dies?
- Lightning destroys the controller?
- The tower collapses?
- Internet linking disappears?
- Fuel for generators runs out?
- Multiple repeaters fail simultaneously?
If your entire Amateur Radio experience depends upon talking through a repeater...
...your communications capability just disappeared.
The operator who regularly practices simplex doesn't have that problem.
Neither does the Weak Signal operator.
They're already accustomed to communicating directly.
Exactly the way Amateur Radio was originally designed.
Emergency Communications Begins With Direct Communications
One of the stated purposes of Amateur Radio is providing emergency communications.
Notice what it doesn't say.
It doesn't say:
"Emergency communications...provided the repeater is still working."
Infrastructure is wonderful...
until it isn't.
History has shown us repeatedly that hurricanes, tornadoes, floods, ice storms, wildfires, and other disasters don't always leave infrastructure standing.
The operator who has learned how to communicate directly station-to-station possesses a skill that cannot be replaced by a taller tower or a more elaborate repeater system.
Amateur Radio Has Always Been About Pushing Limits
One of my favorite things about this hobby is that hams have spent over a century proving people wrong.
How many times have we heard...
"That band is useless."
"Those frequencies are garbage."
"You'll never communicate very far on that."
We've heard it over...
and over...
and over.
Then hams went out and did exactly that.
Six meters?
Called "The Magic Band."
Two Meter SSB?
Hundreds of miles.
432 MHz?
Hundreds of miles.
1296 MHz?
Hundreds of miles.
Microwave?
Thousands of successful contacts.
Moonbounce?
Signals literally traveling nearly half a million miles.
Every generation of Amateur Radio operators has expanded what people believed was possible.
Not by accepting limitations...
But by challenging them.
Our Nets Are Proving the Point
Here in South Texas, our Simplex and Weak Signal Nets continue demonstrating exactly why these activities matter.
Week after week we hear stations checking in from distances that surprise many operators.
Some are using modest stations.
Others have invested in improving antennas, feedlines, mast height, low-noise preamps, or operating techniques.
Many of those improvements happened because someone listened during a net and thought:
"If they can do it...maybe I can too."
That's exactly the kind of inspiration our hobby needs.
I've watched operators upgrade from:
- A handheld to a mobile.
- A mobile whip to a quality base antenna.
- Vertical polarization to horizontal polarization for Weak Signal.
- Fifty feet of lossy coax to quality low-loss feedline.
- Simple installations to carefully engineered stations.
Each improvement expanded their capabilities.
Each improvement made them a better operator.
No repeater could have taught those lessons.
Don't Lower the Standard...
Raise Your Station
If simplex is difficult...
don't give up.
Improve your station.
Raise the antenna.
Replace poor coax.
Experiment with antenna designs.
Learn about feedline loss.
Study propagation.
Try horizontal polarization.
Optimize your equipment.
Ask questions.
Learn from operators who have already traveled that road.
The answer isn't to abandon simplex.
The answer is to become better at simplex.
That journey is where Amateur Radio becomes truly rewarding.
The Culture We Should Encourage
Instead of saying:
"Simplex doesn't work."
Let's ask:
"How can we make it work better?"
Instead of saying:
"You need a repeater."
Let's ask:
"How can we improve your station so you don't?"
That subtle difference changes everything.
One accepts limitations.
The other overcomes them.
The Spirit of Amateur Radio
At its heart, Amateur Radio has never been about taking the easiest path.
It's about learning.
Experimenting.
Building.
Improving.
Teaching.
Mentoring.
Sharing.
Discovering.
If every contact is made through infrastructure built by someone else...
we miss one of the greatest educational opportunities this hobby offers.
Simplex reminds us that our station matters.
Weak Signal reminds us that our imagination matters.
My Challenge
If you've never joined a Simplex Net...
Give it a try.
If you've never operated 2 Meter SSB...
Borrow a radio.
Listen.
Ask questions.
If your station isn't reaching as far as you'd like...
Don't become discouraged.
Become curious.
Every antenna improvement teaches something.
Every foot of added height matters.
Every better connector, every lower-loss feedline, every improved operating technique moves you one step farther down the road.
You may surprise yourself.
And one evening you'll hear a distant station answer your call—a station you never imagined you could work.
That moment is what Amateur Radio is all about.
Not because a repeater connected you.
But because you connected.
That is the spirit of Amateur Radio.
That is why we continue promoting Simplex and Weak Signal operation.
Not because repeaters are unimportant.
But because Amateur Radio has always belonged to those willing to discover what lies just beyond the horizon.
And history has shown, time and time again...
Those horizons are always farther away than we first believed.
73,
Greg Lewis – N5XO Founder, HAMster Weak Signal Group Emergency Coordinator – Bandera County ARES
The Next Chapter for the HAMsters Has Begun!
08/07/26 10:17
