Section 4.4: Connectors #
Ever tried to plug your phone charger into a USB-C port, only to realize it’s micro-USB? That’s the world of connectors in a nutshell. In ham radio, getting the right connection is crucial—it’s the handshake between your radio and antenna.
Let’s take a look at the connectors you’re most likely to encounter as a new Technician, especially if you’re working with handheld radios:
SMA (SubMiniature version A) #
This little connector is like the smartphone of radio connectors—small, sleek, and everywhere these days. Most modern handheld radios use them, but here’s where it can get a bit tricky:
- Major brands like Icom, Yaesu, and Kenwood typically put an SMA-F (female) connector on the radio, which means you need an SMA-M (male) antenna.
- However, many newer brands, especially from China like Baofeng, do the opposite. They use an SMA-M connector on the radio, so you’ll need an SMA-F antenna.
Confused yet? Don’t worry, you’ll get the hang of it. Just remember: whatever connector is on your radio, you need the opposite on your antenna.
BNC (Bayonet Neill–Concelman) #
Think of BNC as the quick-change artist of connectors. It’s got a nifty twist-and-lock mechanism that makes connecting and disconnecting antennas a breeze. You’ll see these on some handhelds and a lot of test equipment. Many hams use adapters on their radios so they can easily switch between BNC antennas, no matter what connector the radio originally came with.
PL-259/SO-239 (UHF Connector) #
Despite its name, the “UHF connector” is a bit of a misnomer. It’s commonly used at HF and VHF frequencies, but it’s not ideal for true UHF work. Think of it as that friend who got a nickname as a kid and never shook it off. You’ll find these workhorses on a lot of HF and VHF mobile and base station gear. They’re rugged, easy to solder, and can handle decent power levels. The PL-259 is the male PLug, while the SO-239 is the female SOcket. These connectors are great for frequencies up to about 150 MHz, but above that, you might want to consider connectors like Type-N for better performance.
Type-N #
Meet the heavyweight champion of RF connectors. Type N connectors are like the armored tanks of the radio world. They’re designed for high performance at frequencies above 400 MHz—UHF and beyond. While they’re a bit bulkier than SMA or BNC, they make up for it with excellent RF shielding and low signal loss. You’ll often see these on serious VHF/UHF gear, microwave equipment, and anywhere precision and low loss are crucial. If you’re working with frequencies above 400 MHz and want the best performance, Type N is your go-to connector.
Understanding Connector Gender #
Here’s a curveball: in the coax world, gender isn’t about threads or outer shells—it’s all about the center pin:
- If the center is a pin, it’s male.
- If the center is a socket (hole), it’s female.
So an SMA-M has outside threads but a protruding pin. This detail confuses many hams and often results in a lot of exchanges with antenna manufacturers!
When matching connectors, here’s the golden rule: match the opposites. If your radio has a male pin, you need a female socket on whatever connects to it. That could be a SMA-F to BNC-F adapter, an SMA-F antenna, or even a SMA-F to SMA-F barrel! (or countless other variations which we will not be enumerating here – you’re welcome)
The Trend Toward BNC #
Since around 2020, there’s been a trend toward using BNC connectors for handhelds with adapters. Why? Because BNC connectors are quick to connect, tough as nails, and versatile. Some hams swear by always using an adapter on their radio to save wear and tear on the radio’s connector.
But, adapters aren’t for everyone. They add a bit of bulk and a tiny amount of signal loss. If you’re not switching antennas often, sticking with what fits your radio directly is totally fine.
Pro Tips for Using Connectors #
- Keep connectors clean and dry: They’re the gatekeepers of your signal, so treat them well.
- Don’t over-tighten: Hand-tight is usually just right for handhelds.
- Be gentle with SMA connectors: They’re tough, but not indestructible.
- Stick to one connector type in your shack: It’ll save you from adapter headaches down the road.
Remember, while adapters can be lifesavers, they’re not ideal for permanent setups. Each connection is a potential point of signal loss or failure. When you can, go for antennas and gear that match your radio’s connector directly.
Understanding connectors might not be the most glamorous part of ham radio, but it’s crucial. It’s the difference between chatting with a friend across town and hearing nothing but static. So next time you’re connecting your antenna, take a moment to appreciate these unsung heroes of the radio world. After all, they’re the ones making sure your carefully crafted signal actually makes it out to the airwaves!