In something that I wrote recently, I referred to “70 cm repeaters,” meaning, of course repeaters that operate between 420 MHz and 450 MHz (at least here in the United States). One of the reviewers took me to task for my use of this phrase, writing:
Another thing that amateur radio gets wrong is the use of terms like 70 cm. WE old hams know what that means, but there aren’t any radios that display a frequency in cm, so in my opinion, it’s best to spell out frequencies and not wavelengths. To rewrite this, I’d say, “440 MHz repeaters” instead.
While I see his point, I’m not so sure that he’s right about this. Back in the day—and I’m talking the 20th century here—we used to call the 70 cm band, the 440 band (at least here in the Midwest). Note that we’d say “440” and not “420,” because most, if not all, the repeaters were located at the top end of the band.
Now, however, I think it’s becoming more common to hear 70 cm instead of 440 MHz. Why call that band 440 MHz when we refer to all that other bands—at least all those lower in frequency—by their wavelengths? What I suggested is that I re-word “70 cm repeaters” to read “70 cm-band repeaters” or “repeaters for the 70 cm band.”
In his reply to this suggestion he wrote:
To each his own, I guess. In my writing, I’m trying to make amateur radio seem accessible and inclusive to those who aren’t currently hams, but might be interested. I’m not trying to “dumb it down”—my intended audience is techies—but I think that one only understands wavelength measurements once you’re on the inside of amateur radio. To a non-ham it’s cryptic to say 70 cm; non-ham wireless experimenters are used to seeing 433 MHz, 900 MHz, so that’s why I use frequencies, not wavelengths.
I think that perhaps what I’ll do is to continue to refer to the band as the 70 cm band when writing for amateurs, but be more specific when I think that non-amateurs will be part of the audience. For example, I might refer to “repeaters operating in the 70 cm band (420-450 MHz).”
What do you think?
At 40, I still feel like a youngster in this hobby. So I don’t know anything about how things were “back in the day”. What I can say, however, is that wavelength has always felt more intuitive to me when it comes to understanding the science. It’s much more tangible. Sure, even car radios show MHz, so that’s the more familiar system, but once you want to understand what any of the numbers actually mean, I think metres are easier to grasp, and the exact opposite of cryptic. Wavelength was also covered extensively in school, at least in my experience, in relation to light, the ocean, math in general. Hertz, I don’t know, I guess they might have mentioned it!?
My partner is an astronomer, and probably feels some kind of way about this subject, but for most ham radio purposes I think it really comes down to preference. At some point the systems become almost interchangeable–it certainly can’t hurt to provide both and make that point come sooner!
I like the idea that wavelengths make the concept of radio waves more tangible somehow, that Wavelength is something that can be visualized more easily than frequency.
Every area of specialty has their own jargon. It’s not the specialists job to avoid using the jargon (because it’s a common language that facilitates faster communication in the area), but it’s their job to explain what the jargon means when needed (maybe, I don’t know, by writing books about it?). If people are interested in learning about ham radio, then they’ll need to learn the jargon. and flipping frequencies and band wavelengths is about one of the first things I remember learning when I started studying ham. Plus, like you said, we use the wavelength designation for all the other bands.
Bands are often indicated in meters while frequencies are in Hz.
I’m pretty sure that the old hams never called it the 3 MHz band, it’s always been 80 meters.
And that’s why 70cm is quite okay, although I generally call it 440 MHz, but then again Europe uses 430 MHz, so 70cm is a little better when talking to a broader audience.
Dan,
I think I call the two 449mhz repeaters I administer just that: 440 repeaters. I also call them 70 cm repeaters. I’ve NEVER had anyone get confused about the band they’re operating on. Your critic can call them what he chooses but new hams will run into both sets of terms. They are out there and no set of comments will change that.
73s (know what I mean?)
Frank
K4FMH.
I think you’re right in going with whatever is more comfortable to the audience: “70 cm band” for hams and the full spell-out of “70 cm band (420-450 MHz)” or similar for everyone else. What’s more, in casual conversation even saying “band” to most hams can be a little redundant; e.g. “see you over on 70 cm” ought to be enough.
Or we could just go with the really old-school designation: 1.53 cubits!
Dan,
Funny thing, I was just pondering the same issue as I prepare to teach a Technician Class this weekend.
I think this is an issue: it is so easy for us to flip back and forth between frequency and wavelength, without even realizing it. Experienced hams know that 14 MHz is the same as 20m but someone new to the party just doesn’t make that connection very quickly. I’ve caught myself saying things like “a lower band such as 40m might work better than 2m”….what? when did the number 40 become lower than 2?
I think we need to be careful and go slow with new folks on this topic. I am going to avoid flipping back and forth casually between wavelength and frequency. But I don’t think we can shield them from it completely. They will encounter both frequency and wavelength when learning about amateur radio.
Bob K0NR
It is really interesting how things just make sense when you’re used to them; I’ve been a ham for less than two years and I didn’t realize why your 40m vs. 2m quote would be confusing until I read the rest of that paragraph.
73, Sam KJ7RRV
“What do those letters and numbers around your name mean?”
30MHz and below – use meters. Above – use frequency.
The usefulness of meters is the convenience of antenna use for wire antennas. Above 30MHz there’s very little need or use to think about the wavelength – you aren’t creating an antenna in the field from a random roll of wire.
A foolish consistency is the hobgoblin of little minds, it is said. Yes we almost always refer to wavelength when talking about bands from 160 meters to 2 meters, but I hear 136 and 472 kHz more often than 2200 and 630 meters.
The specific problem I have with “440” is that it implies our allocation is only 440-450 MHz. Some business interests would like to take 420-440 away from amateur radio.
I appreciate the reviewer who wrote 70 cm repeaters are 440 MHz repeaters, your response, and all the other comments.
Thank you for this blog and the comments, all very helpful.
In three weeks I will take the exam to get an FCC Technician License. I am a non-ham who has wondered about the various designations used to identify bands.
Here are two questions and answers in the 2022-2026 FCC Technician License exam:
T2A03 (A is FCC answer) What is a common repeater frequency offset in the 70 cm band?
A. Plus or minus 5 MHz
B. Plus or minus 600 kHz
C. Plus or minus 500 kHz
D. Plus or minus 1 MHz
T8B08 (B is FCC answer) What is meant by the statement that a satellite is operating in U/V mode?
A. The satellite uplink is in the 15 meter band and the downlink is in the 10 meter band
B. The satellite uplink is in the 70 centimeter band and the downlink is in the 2 meter band
C. The satellite operates using ultraviolet frequencies
D. The satellite frequencies are usually variable
The wavelengths are approximations. We use them as the names of the bands.
Amateur Radio, like any specialised interest, has many unique cultural practices. One of these is giving names to each of our bands, and those names are, usually their approximate wavelengths. This practice is rooted in the days when it was easier to measure wavelength than frequency.
3.750 MHz is the exact frequency at which 80 metres is the wavelength. 3.703 MHz is 81 metres. 82m is 3.659 MHz. We use the term “80 metres” to describe the band,
Similarly, 70cm is the wavelength of 428.6 MHz. That’s not even an Amateur frequency in most countries, but the term “70cm” is a nice, convenient name for the band.
I do recall one penadtic twit who would call “CQ 42” when operating on 40 metres SSB. This now-departed soul was trying to make a point that no one cared about. He is not missed.
When I first started looking into AR it was confusing. Without the help of a mentor during the Covid lockdown a lot of things made no sense. It was not intuitive for example that the bands increased in number as the frequencies decreased in number. So I guess you really do have to know your target readership audience.