Going Long-range with Transequatorial Propagation (TEP)

I just sent a radio message that was heard 5622 miles away, in Chile! 

I didn't use an Internet provider; no smartphone, no satellites... I didn't even have a big antenna (though, I want one).  

How did I do it? 

Contact with Chile

Well, I've got a nice HAM radio rig connected to a pretty low-tech antenna. But, what really helped was something called Transequatorial Propagation (TEP). TEP is a phenomenon that allows radio signals to travel much farther than expected when communicating across the equator. 

"Propagation" is the term used to describe how radio signals travel. 

Sometimes propagation is more direct. Signals are radiated from a transmitter and, for a certain distance, they are received clearly, provided there is a line-of-sight between transmitter and receiver. This is similar to how my UHF/VHF rig, and scanner, work. Regardless of the conditions, day or night, I can use my UHF/VHF rig to contact others within about 50 miles in all directions. Radios used by the Police, Fire, and Civil Service in my area do the same thing. They are very reliable within a certain range, but cannot propagate farther than that. 

The great thing about "HAM" radio is that we can experiment. We're not emergency workers or broadcast stations, so we can chat, or call out "CQ" to check if anyone is out there to talk to. In doing so, we can actually use our modest radios and antennas to communicate MUCH FARTHER than a standard commercial radio, by using propagation.

FT8 Contact with Chile

I've written other articles about propagation, but I have yet to really describe Transequatorial Propagation (TEP)... Perhaps because I didn't quite understand it when I was using it. 

But it all makes sense now. I've been able to regularly contact, through both phone/voice and digital messaging, South America -Argentina, Brazil and Chile- with relatively low power. 

It's all because of Transequatorial Propagation! 

Transequatorial Propagation (TEP)

As I have mentioned on The Cublical Ruins before, radio propagation is often assisted by ionization of molecules in the upper atmosphere. Ions in the "F" region of the atmosphere, in the right conditions, will reflect radio waves, and send them cascading over a much larger range than the original transmitter can send on its own. 

Night and day, Winter or Summer, there is always more Ionization near Earth's magnetic equator. It's receives the most sunlight year-round, and creates an equatorial field of ions and charged particles. This field creates a mirror (of sorts). It can amplify, and reflect, radio signals going directly across it! 

So this is why -on an otherwise bad day for radio- I can send a low-power signal, and get a response from Chile or Argentina! I used the Sun, sub-atomic particles, the ionization in the atmosphere and Transequatorial Propagation, to send my signal... 

Science is pretty cool!               

Introducing the HAM Radio Widget

Now you can check in on my HAM radio adventures!

In keeping with the goals of The Cubical Ruins: to write, practice web development and provide readers with some insight into my life and experiences, I added a new widget to the homepage... 

Check out the new "HAM Radio Contacts" widget, on the right-hand navigation menu of the website. Like the "What's Up There" widget above it, you can click and drag the HAM radio widget to see where I've made recent contacts with my radios.

 

HAM Radio: Improving Range with Antenna Design

My new antenna design

I have two "HAM" radio antennas on my house currently. One is very obvious. The other is hardly noticeable. The obvious one (the big white pole out front) is my VHF/UHF antenna for transmissions in the 2 meter and 70 centimeter range- a potion of the HAM radio spectrum similar to AM/FM radio, which most people are more familiar with. 

The not-so-obvious one is a wire-system fixed to the side of the house which is hidden from the street. 

To a lay-person, the capabilities of these antennas may be misleading. 

My "big" antenna system; the VHF/UHF transceiver is very useful. However, at its highest power, it can only transmit roughly 60 miles in all directions. Meaning I can talk to northeast Ohio, western Pennsylvania, and maybe West Virginia and Ontario on a good day. Still, there are advantages to the fast-wavelength UHF/VHF bands. Day or night, I can use my ICOM IC-2730 transceiver to connect with people clearly in my region. Neither weather, solar, or atmospheric activity will interfere with my UHF/VHF signal. This is why FM radio stations (and most police and fire departments) communicate on the UHF/VHF bands: Because signal strength is guaranteed within the local region no matter what. In an emergency, I'm happy to have my tried-and-true VHF/UHF rig, because I know I can use it to get in touch with people close enough to my location to help if needed. This is same reason FM radio uses similar wavelengths; because they want their music, news, and programing to be available to everyone within a certain distance, no matter the conditions. 

My existing UHF/VHF antenna

But as an amateur radio enthusiast, I don't simply want to talk to people in the next town over. The fun is contacting people world-wide! (even when it's not an emergency).

So, I set up my "HF" rig with the Yaesu FT-891 and a very simple end-fed antenna that should be able to get my signal farther than Pennsylvania. I wrote about it in this blog! 

In the hands of an experienced radio operator, HF radio waves (which have a lower frequency than VHF/UHF waves) can travel world-wide, if propagation and conditions are right. However, sometimes atmospheric conditions simply aren't conducive for HF signals. And, even if a signal can be heard thousands of miles away, it takes two talented radio operators to send/receive the signal. Interference from weather, solar activity, nearby electronics and genuine randomness, make HF radio a challenge even for the most experienced operator. So, while an HF wave can bounce across the world, it's never as reliable as the UHF/VHF waves we rely on to listen to FM radio, or critical emergency communications. 

However, there are many ways to improve HF propagation and make world-wide amateur radio communication more reliable. One, is antenna design. 

My new HF antenna

My first HF antenna, which I documented here on Cubical Ruins, was about as simple as an antenna can be. In HAM radio, we call it an end-fed "random wire" antenna, because it's basically just that. It's a copper wire strung as high as you can get it. And, it worked! On a good day, when conditions were perfect for global propagation, I actually used that antenna to speak with a gentleman in Southern England from my station in Ohio. I heard him clearly, and he heard me. I was using only 40 percent of the available power on my transceiver. So, it's very easy to make an HF antenna. Basically you just need a metal wire, and a radio! (but, an antenna tuner like the LDG Z-11 Pro and network analyzer like the NanoVNA do help A LOT). 

Eventually it was time to design a new, more permanent, HF antenna. I had a design in mind for a while. I just needed the weather, and time, to set it up. I would go from an end-fed "random wire" antenna, which transmitted from the basement window where my rig was, to as high as I could hang it (about 17 feed up the side of the house), to a horizontally-aligned dipole. 

Unlike the old "random-wire," the dipole would uniformly transmit at a height of about 12 feet above basement window, and from two points at the far sides of the northern end of my house. This means that total the total radiating and receiving portion of the antenna would be both longer, and higher-up, than the previous antenna.  

The result looks like a "T" shape with the radiating antenna crossing horizontally across the house, and the "unbalanced" coaxial line that attaches the antenna to the transceiver making the "stem" of the "T", which terminates at the basement window where my radio is. The entire system, like the UHF/VHF system, is now grounded to reduce electronic interference and to mitigate lighting damage to the home -yet another improvement on my old "random wire." 

At the very least, the new design is more permanent. It's solidly fixed to the house, and has survived two major thunderstorms with significant wind-gusts already. Plus, it now has a lightning arrestor, which definitely makes it a safer long-term antenna than the previous one. 

Contacting Azores with the new antenna

PLUS, it looks like the performance of the the new dipole has improved as well. On the first day I tested the new deign, I made contact with stations in Venezuela and The Azores! And, Los Robles, Argentina, a whopping 5.5 thousand miles away from my location using only 60 of my available 100 watts of power.   

Like any scientific inquiry, it will take a while to truly determine if my new set-up is success. But, transmitting, receiving and collecting data is part of the fun of HAM radio. It's an experiment to see if my new design is an improvement... or if I should go back the drawing board (so-to-speak). 

For now my new antenna works! And it seems to work well.