HAM radio is one of the most popular amateur radio hobbies in the world and its been around for a long time. Though you have to have a license to transmit, you’re free to listen as much as you want to. If you do obtain a license, you’re part of a family of amateur radio hobbyists for life.
HAM radios don’t have a limitation on their range. If you have a powerful enough antenna and the atmospheric conditions are right, you can transmit clear across the US or even farther. It also depends on frequency, namely UHF, HF, SHF, EHF, and VHF.
A lot depends on your power and the atmospheric conditions at the time. For instance, it will be harder to push a signal through lightning storms than it will across a bright and sunny day. You can expand your range as well, by upgrading your equipment.
Different Frequencies
The frequency you are using makes a huge difference in how much range you have. The two longest wave frequencies are VHF (Very High Frequency) and UHF (Ultra-High Frequency.
UHF and VHF are comparable except for two things: obstacles and open space. For open space, VHF frequencies are great because they can travel a pretty long distance. If you are broadcasting out over open water and your room has a lot of open windows, VHF is fantastic.
However, VHF is a lot like WiFi because it doesn’t play nicely with common indoor obstacles such as wood, concrete, sheetrock, and metal. UHF, on the other hand, is great for indoor use. It fairs much better against thick concrete, wood, metal, glass, sheetrock, and more.
When you want to maximize your reach, it’s a good idea to jump on the frequency that best matches your location.
Antenna
If you’re at least 40 years old, you probably remember the importance of antennas when it comes to picking up signals. The old rabbit ears on top of the cathode ray TV are a prime example. We still use antennas today, even residentially, including for picking up local High Definition channels.
One of the biggest contributing factors to your range is the height of your antenna. The size of your antenna matters as well but getting it set up as high as it will reach is a good start. When it comes to transmission, “line of sight” is important when you get above 2 megahertz.
There is actually a formula for determining your range according to how high your antenna is. Distance = Height x 1.415. Simple enough. All you need to do is determine the height of your antenna in feet.
If your antenna is attached to your chimney, 20 feet up, your distance/range of transmission will be 20 x 1.415, which comes to 28.3 miles. The higher you get your antenna, the higher your line of sight transmission range.
Power
Also known as signal strength, the power behind your transmission capabilities plays a large role in your range as well. A standard, local radio station might broadcast at 75,000 watts, which is exponentially higher than anything you can legally do.
In fact, most HAM radios are limited to between 2 and 5 watts, depending on the brand and its capabilities. You will get a lot more range out of a 5-watt HAM radio than you will out of a 1.5-watt, small HAM radio. Of course, that makes plenty of sense. If you want to maximize your range, you need to maximize your power.
Topography/Obstructions in Your Line of Sight
If you’re broadcasting from a valley, it’s not as easy to get a lot of range through a mountain as it is for someone to transmit out on the plains of Montana or North Dakota. If you’re dealing with a lot of obstructions and you live in an area with mountains and high trees, UHF is your best friend and even then, it will be weakened.
All Things Considered
The typical range for a HAM radio is 18 miles but HAM radios are known for reaching vast distances. Of course, the people that are transmitting across those distances are probably in open areas, with plenty of power, very high antennas, and are taking advantage of line of sight, VHF frequencies.
