Foundations of Amateur Radio
The question that new amateurs most often ask after "What radio should I buy?" is "How do I get the best antenna?"
In a household where you're the only antenna affected aficionado the question is likely more along the lines of: "Why do you need another antenna?"
The answer is pretty much the same, an antenna is fit for purpose, generally only one purpose.
Going from A to B without walking might involve a car. If it's just you, one seat is enough, if your local cricket team is coming too, you might need more seats. If the road is rough, you might need a good suspension and if it's the middle of summer in Australia, air-conditioning isn't a luxury but a necessity.
Each of those different requirements varies depending on circumstance and need. There are plenty more variables, fuel, distance, cost, and the deeper you dig, the more choices.
Antennas are no different.
While cars have an element of fashion, colour, styling etc. antennas are more utilitarian, radio amateurs rarely care about the colour of their contraption, but they do care about cost, construction and performance.
Those three variables alone would make for plenty of choice, but we've not yet talked about some other variables that come into play.
If you're a licensed amateur, picking the frequency you want to use is obvious and a major factor in the choice of antenna, but if you're not an amateur, that's not something obvious, but you have seen it before.
Without going into the physics of how and why, imagine all the antennas you've seen in your life. There's a TV antenna on the roof, the antenna on a transistor radio, an antenna on a car, the antenna on your Wi-Fi modem, a mobile phone antenna, satellite dishes, you might have seen antennas near train lines, on top of traffic lights, on a GPS and on a satellite phone. You might not be familiar with all of them, but enough to know that there is a huge range of different types of antennas. The more you look, the more variation you find.
You might think that each of those different antennas was chosen at the whim of the person spending the money, but actually, each of those antennas was chosen for a specific job. Each of those antennas works on at least one frequency, sometimes more and does so taking into account its purpose. Is the antenna for sending, or receiving, or both? Is it supposed to work regardless of where it's installed, or how high off the ground it is? Does it need to take into account interference from a particular direction? Is it meant for strong or weak signals, does it need to have a defined lifespan, deal with a particular wind strength, etc. etc.
Answering each of those questions determines the choices made to select an antenna from the infinite variety available.
As an amateur, my licence allows me to operate in six different frequency ranges or bands. Technically that means at least six different antennas, just so I can use the frequencies I'm licensed for.
Of course I'm only scratching the surface here, since I've already explained that antennas come in many different shapes and sizes, each with different characteristics and trade-offs.
So next time you wonder why so many different antennas, that's why.
If you've been wondering when I'll answer the bit about the best antenna, you should already have a clue by now, but the real answer is unsurprisingly: "That depends."
"On what?" you ask.
On which ever variables you care about and to which degree. The best antenna depends on the questions you ask. Ask better questions, get a better antenna.
I'm Onno VK6FLAB
To listen to the podcast, visit the website: http://podcasts.vk6flab.com/. You can also use your podcast tool of choice and search for my callsign, VK6FLAB. Full instructions on how to listen are here: https://podcasts.vk6flab.com/about/help
All podcast transcripts are collated and edited in an annual volume which you can find by searching for my callsign on your local Amazon store, or visit my author page: http://amazon.com/author/owh. Volume 7 is out now.
Feel free to get in touch directly via email: firstname.lastname@example.org, follow on twitter: @vk6flab (http://twitter.com/vk6flab/) or check the website for more: http://vk6flab.com/
If you'd like to join a weekly net for new and returning amateurs, check out the details at http://ftroop.vk6flab.com/, the net runs every week on Saturday, from 00:00 to 01:00 UTC on Echolink, IRLP, AllStar Link and 2m FM via various repeaters.