Chris Warren at Off Grid Ham has written an off grid radio guide for those who are beginners to working their radios without mainline power. There are a bunch of useful links at the end of his article, too.
The demand and desire to take amateur radio off grid is absolutely there. The problem is that information about off grid radio is sprinkled around. It’s hard to find straight answers. Many radio and survival blogs occasionally address the issue, but to my knowledge, Off Grid Ham and OH8STN are the only two outlets that deal with off grid radio radio exclusively.
For readers who are not off the grid, or seek to expand off grid capabilities, I’ve put together this “off grid radio guide” for beginners that will answer the most common questions in one compact package. This is not a comprehensive guide; we’re just going to summarize main points. At the end of this article there will be links to additional information on the topics covered here.
Have a purpose!
I’ve beaten this drum so much it may seem tiresome, but it cannot be overstated that having clearly defined goals is an absolute must. If you do not have a specific purpose in mind, then you’re just going to trip around randomly trying different things with no meaningful result. If you have the time and money to spend on dead-end projects, then by all means don’t bother with a roadmap; you’ll eventually find your way and probably have a great time doing it. Off grid radio guide
But for those of us who do not have the means to live like plans don’t matter, the first chapter in our off grid radio guide is to have a purpose. Your stated goal does not have to be complicated or lengthy. Here are a few examples:
- Operate for a weekend or so while camping.
- Helping kids/scouts/youth group with an educational project.
- Involvement with contests and SOTA/POTA activities.
- Energy independence/operate off grid full time from a home station.
- Survivalist/prepper communications for when SHTF.
- Curiosity/self improvement. Off grid radio guide
Your goals may change over time. I originally got into off grid ham radio just to experiment and fool around with solar panels. That lead to a large home station, several portable power setups, and this blog! Regardless of what your motivations are, make sure you can define them.
How much power will you need? Off grid radio guide
Answering this question is a major component of defining your purposes and goals.. After all, it doesn’t make sense to plan a power system without knowing how much power you’ll need.
If your plans include an engine-driven mechanical generator, choose one that will run at 33-50% of its maximum capacity while powering your equipment. This is the window where generators are the most efficient. You don’t want to push a generator close to its limit for extended periods, nor do you want a generator that is way oversized for the load it powers. Either of these two extremes are a bad idea.
Matching power needs to batteries is a very tricky dance because a battery’s performance can change with age, temperature, previous use, and physical condition. A handy rule to follow is that whatever number you come up with for your needed battery capacity, increase it by 50%. This will give you plenty of wiggle room for inherent factors that degrade battery capability.
When determining battery size, carefully consider the expected duty cycle you’ll be demanding of your equipment. Duty cycle is a ratio, expressed as a percentage, of transmit time to receive time. The more you transmit, the higher the duty cycle and the more battery you’ll need. At a minimum, figure a duty cycle of 25% and up to 80% if you run a lot of data.
Solar panel calculation.
No off grid radio guide would be worthwhile without discussing solar panels. The biggest variable is the sun itself. On a cloudy day, you may realize only 10% of your panel’s capacity. A solar panel will never hit its rated maximum power due to the varying levels of sunlight and the inefficiency of the system. Like batteries, include generous headroom in the form of more solar wattage capacity to make up for the losses…
The Medic Shack: The Powergrid. Is it as screwed up as we think it is?
The Smart Survivalist: Off-Grid Batteries and Power Systems
The Smart Survivalist: How Much Does it Cost to Live Off Grid?