- rotor/rotator - one is a part, the other is the whole mechanism
Not really. As posted elsewhere, the two terms have been interchangeable for over 50 years. Alliance Tenna-Rotor, anyone?
- diplexer/duplexer - one splits/joins signals, the other keeps them separate
Nope. Looks like you've run afoul of a version of Muphry's Law (that's not a typo).
A diplexer is a splitter/combiner that is frequency selective so that one band of frequencies goes in/out of one port, and another band goes in/out another port. For example, consider an old analog TV with separate UHF and VHF tuners, connected to a common VHF/UHF antenna. A diplexer would route the VHF signals to the VHF tuner and the UHF signals to the UHF tuner.
A duplexer is a device that permits duplex operation (simultaneous transmit and receive) with one antenna and feedline. The most common example is a repeater duplexer.
- CW/Morse - one is a modulation technique, the other is a way of sending information
In a narrow context, "CW" stands for "continuous wave" - meaning an unmodulated carrier. "Morse", (meaning the code), is the code itself.
But in ham radio for the past 70 years or so they mean the same thing.
Here's how the term "CW" came about:
The first radio transmitters were spark sets. They generated a "damped" (modulated) wave, which could be received on just about any receiver. No BFO needed. You'd hear a buzz, not a pure tone. Various kinds of spark transmitters had different sounds but they were all damped waves, and they took up quite a bit of spectrum because the modulation was rather extreme.
So it wasn't long before radio transmitters were developed which generated an "undamped" (unmodulated, or continuous) wave. Arc converters, high frequency alternators, and finally tube transmitters generated "continuous" waves, which required heterodyne reception. "CW" became the acronym, to differentiate them from spark. Both used Morse Code, so there was no reason to include that part. When spark transmitters disappeared, the term "CW" stuck with all Morse Code transmitters because it's so short and concise.
btw, the modulation technique most often used for Morse Code is on-off keying, abbreviated "OOK". But nobody with any sense uses such a term in amateur radio; "CW" is just fine.
- SO239/PL259 - one is the socket, the other is the plug
Well, yeah, that's why one begins with SO and the other with PL.
Of course we can figure out what is being said. I just thought it would benefit those who don't know to know the actual names of parts.
True, but it's important to get the names right.
What misnomers have you seen creep in to the hobby?
Well there's "balum" instead of balun. The use of all-capitals "HAM" instead of "ham" (it's not an acronym). Don't know where they came from.
There are hams who can't spell "amateur" or "transceiver". Hams who don't know the difference between a key and a keyer.
Pretty minor stuff, really.
Of course there's the usual confusion about spelling, grammar, punctuation, etc., which is common all over - hams don't have a corner on not knowing the difference between:
and many others. Not that big a deal, really.
What IMHO *is* a big deal, and worth discussing, is the all-too-common myths, misunderstandings, urban legends and downright lies which too many believe - and spread.
- the USB/LSB origin myth
- the "antenna tuners protect the transmitter from reflected power by dissipating it as heat" myth
- the "lossy traps" myth
- the resistive-loaded antenna myths
- various grounding myths (my favorite is the coax-with-disk-capacitors one)
- various origin-of-term myths about "ham", "73", etc.
- all sorts of myths about linear amplifiers and tubes, particularly transmitting tubes.
And much more. Some are just dumb, some are costly, some are downright dangerous.
Don't get me started about cathode resistors in Kenwood hybrid rigs....
73 de Jim, N2EY