Now that you've ordered your radio, you're going to need to order an antenna. This section is only focused on VHF/UHF antennas because HF antennas are an entirely different creature.
Also CB ANTENNAS ARE NOT HAM RADIO ANTENNAS. CB's are AM (amplitude modulation) and about 11m wavelength, you're looking at 2m/70cm wavelengths on FM (frequency modulation).
It seems complex but we're going to make it simple.
There are three things to know about the antennas, and then a few different types of mounts.
First - CONNECTORS:
The "PL259" (just memorize that, you'll be using it all the time) is the standard connector for most UHF/VHF radios.
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| PL259 Connector (Male) |
The PL259 goes onto an "SO 239" connector (just memorize it, you'll be using this all the time too).
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| SO 239 (Female) |
This is usually what's on the back of most mobile and larger base-station radios.
There are other types of connectors we use with ham radio, including Type-N, BNC, and SMA. If you bought a Baofeng UV5R you probably noticed an SMA connector from the antenna to the body, other handhelds may have a Type N or BNC adaptor. For mobile radios, we're typically going to find PL259's going onto an SO239.
When you buy an antenna, make sure it has the right connector for your radio on the coaxial cable (coax).
Second - RESISTANCE:
Going to get a bit technical here, most ham radios are set for 50Ω (ohms) resistance - covered in your studies for your Technician license. That means the antenna and the coax also need to be set for 50Ω resistance. If you get something higher (75Ω) or lower, it is not good for your radio, higher resistance creates heat and reduces your signal, lower resistance can also cause the radio to heat up as the radio doesn't have its required resistance, essentially just letting electrical power course through it and that can heat it up and blow your radio as well.
Third - BANDS.
Some antennas are meant for 2meters, some are "dual channel" (2m/70cm, or VHF/UHF), some are just for UHF, some are for HF, some are CB antennas (which is an entirely different creature).
If you got a regular VHF/UHF mobile radio, you're going to need a "dual band" antenna. If you got just a VHF radio, a dual band antenna will work, so will a 2m antenna or VHF antenna.
As for antenna mounts, you have a few choices:
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| Magnetic mount or "mag mount" antenna |
- Magnetic mount - the easiest to install - simply goes on your trunk or on your roof and you run the wire through a crack in the trunk or out your door. You can leave it up all the time or only put it up when you want it. If you're like me, you'll be on the radio a lot when driving so you'll leave it up. Mine just went on the trunk of my Acura and I ran the wire through the lip of the trunk just under the window. Here's the mag-mount I bought for my Acura. The coaxial cable / feed line ("coax") was long enough for me to just run the wire back from the radio through a small gap between the seats in the back into the trunk. Mag mounts can scratch your paint, so make sure you clean under it or wax under it, putting a cloth under it can trap water and dirt and further scratch it, you'll have to experiment and pay attention. This is the closest thing to a plug-and-go.
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| Lip mount |
- Lip mount - a lip mount goes on the lip of the trunk or hood of your vehicle (beware if your lip is angled, unless you make an adjustment for it, the antenna will be angled too and beware how your trunk/hood opens so you don't put your antenna into the glass and shatter a window). Here's one such configuration. Only drawback to a lip mount is the antenna uses your vehicle as part of the "ground plane" or a reflective surface to make your antenna more effective. When you put it to the side (versus in the middle of the trunk or roof) you lose about 1/2 of your ground plane, which you may notice differences in propagation in different directions in theory (results will vary at different times). Mine works just fine with a fender mount on the side (see farther on in post).
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| NMO mount - through roof |
- Through roof/trunk - NMO mount (New Motorola) - this requires you to drill a hole in your vehicle and then put the connector through to the antenna on the top. Pretty much a permanent arrangement. Reportedly the best configuration because of the interaction between the radio waves with the vehicle body as the ground plane and not dealing with a magnet mount underneath the antenna, but I'm not a fan of drilling into my car's body, plus I can't take it off if I need to go through the car wash, and I don't want my vehicle to leak (not a problem if you seal it). My mag mount works extremely well for anything I use it for.
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| Glass Mount Antenna |
- Glass Mount - no you don't have to drill a hole in the glass. You stick one part with an adhesive on the outside, and one part on the inside and the two sides act like a capacitor sending the signal back and forth through the glass. This is great if you don't want to scratch your paint, have a nice-looking car or truck you want to have the antenna accentuate its look. Just beware not to put it on window defrosters and they don't work as well through window tinting (the blue part). Glass mount antennas may come with a Type N, SMA or BNC adaptor, so you'll need to check to make sure that you get feed line with the correct adaptors on both ends, which can be bought or made (easier than it sounds, you'll get good at soldering, cutting and splicing coax if you do this enough, but that's for another post. If you can, just buy what you need and make sure you have the right length).
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| Fender Mount Antenna |
- Fender Mount Antennas - I have one of these on my van. Make sure your mount will fit your vehicle, or be prepared to do a bit of metalsmithing in your garage to make it fit. I ended up putting mine next to the vehicle's stereo antenna because there's no radio interference on that side (the stereo just listens, and they had to put it someplace it wouldn't have interference and I haven't had any problems with my stereo by having it there - results may vary - might suggest not having the car stereo on at the same time you're using your ham radio if you do that arrangement). When it I had it over by the battery, there was so much radio interference from the battery that I couldn't even get a signal out a block's distance. You can also get mounts for your bumper.
- For the fender mounts, make sure they have the right size hole for your antenna. Usually you'll need an "NMO Mount" - nothing like buying a fender mount for a CB antenna and your ham radio has an NMO mount that doesn't fit.
You can also buy a compact NMO antenna, you'll often see these on police vehicles. They are very small, not even a few inches, and you can drill those through the trunk or roof or put them on a fender mount or a lip mount. They have coil inside that makes the antenna "longer" so that it works better than having a 2" antenna. Remember though, police have far more repeaters, work in more predictable areas than hams do. However, if you try this and it doesn't work, you can switch to another antenna that has an NMO mount for 2m/70cm and try that out. Much of what hams do is experimenting.
My opinion? When getting started, go the simple route, a mag mount. You can easily change that later, it has no drilling required, it's the fastest setup.
There's a few different types of antennas, the most common is a "quarter-wave" (meaning 1/4 of 2m) with a coil in the middle of it (the coil allows the antenna to be shorter while still giving the effect of it being longer). You can have straight antennas (whip) or they may have a little segment in the middle. So long as you have the right connectors, right impedance (50Ω), right bands, you should be just fine.
I prefer buying an antenna that has the feed line with the connector already put on for me, I'd recommend getting the same while you're starting out so you don't have to learn to solder and cut or splice coax, it's already matched (meaning the impedance is set to match your radio at 50Ω), just plug and play.
So - all you have to do is look for a dual band antenna, make sure it's 50Ω, pick the mount, make sure the connectors fit and you'll be ready to wire it up.
As always there's more, but this is just a starter. I can't write every variable in a single article and you wouldn't want me to, but this is enough to get you going.
Next up: basic mobile electrical wiring!
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