# Why is the 70cm band commonly referred to as the 432MHz band?

I keep reading and hearing the 70cm band (420-450 MHz depending on local regulation) referred to as the 432 MHz band, particularly by older hams. Why?

• In some countries, the band starts at 432 MHz. It would be interesting if someone could dig up historical band edges of the 70 cm band around the world and see how they changed over time. I know that in some countries, edges below 432 MHz were added later and in some are for secondary use. My personal conjecture is that the band was expanded over time and that older hams still use older frequencies. I'll post an answer, if I dig up some interesting information. – AndrejaKo Jul 2 '15 at 14:20

I assume it's because the national calling frequency is 432.10, and a lot of the signals of interest in the ARRL band plan are around 432. Repeater work is usually higher of course, but there is still plenty of interest around 432.

• This sounds somewhat US-centric to me. In the UK, repeaters are around 433MHz, and the band is only 430-440MHz. (And in some countries, there is no allocation at all.) Check out this web page, too - this from the Radio Society of Great Britain : rsgb.org/main/operating/band-plans/vhf-uhf/432mhz-band – Scott Earle Jul 2 '15 at 10:38

The 2m band is sometimes referred to as the 144MHz band, and the 3rd harmonic of that is 432MHz. I have heard the 23cm band referred to as the 1296MHz band, too - for the same reason (3rd harmonic of 432MHz and 9th harmonic of 144MHz).

A lot of people in the United States refer to the 70 cm band as “440”, because that’s pretty close to where the repeaters in the 70 cm band start.

• Agreed, I'm a new ham but so far I've only heard it called the "440" band by other hams more experienced than I am. Although my Icom ID-5100A shows it as the "430" band (not "432") when you change bands. – Paul Nov 15 '19 at 21:35
• Probably because that's where the frequency band starts, however I'd have to check the band plans to see where the band starts. Feel free to demote my comment if I'm wrong. – lmaverickbna Dec 5 '19 at 19:29
• The band is from 420-450MHz but the repeater section of the band is between (roughly) 440 and 450. arrl.org/band-plan – Paul Dec 5 '19 at 22:07

The reason it is called the 70 cm band is because the approximate wavelength of an RF signal in that band is 70 cm. If you recall, wavelength in m = frequency in MHz / 300. 432/ 300 is about 0.7m or 70 cm.

• The question is asking about the 432 MHz name, not the 70 cm name. – Kevin Reid AG6YO Jul 3 '15 at 0:15
• Well, the equation works in reverse, too. :) I'm an "older ham," and I've always called it the 440 band, almost never 70 cm. – Dan KB6NU Jul 4 '15 at 1:05