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Chetiya Sahabandu

Identifying Communication Frequency-Band Allocations

August 20, 2010 —
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This week BBC News ran a story on how taxi drivers in Japan are hearing the unexpected sounds of cooing babies on their CB radios. The cause: U.S.-purchased baby monitors from nearby U.S. military bases that are interfering with communication frequencies. Why would this happen? It’s likely that the baby monitors were manufactured to work on region two communication frequencies, and while being used in Japan, they’re interfering with communication frequencies allocated to region one.

The International Telecommunication Union (ITU) divides the world into three regions. Each region has its own frequency-band allocations; that is, in each region, each frequency band is allocated to a specific use. Sometimes a local authority like the Federal Communications Commission (FCC) in the United States regulates the use of frequency bands.

Say you want to find out how a specific frequency like 2GHz is allocated. Type “frequency allocation 2GHz” into Wolfram|Alpha.

Frequency allocations for 2GHz

Here you see FCC allocations for the United States (ITU region two). In the pod at the bottom, you see the allocations for all three ITU regions. You could of course have asked the same question in terms of a wavelength by typing “frequency allocations 15cm“.

Frequency allocations 15cm

You can also find the allocations by location, for example, “frequency allocation 2GHz Japan“.
Frequency allocation 2GHz Japan

Or you may give a more local location such as “frequency allocation 5GHz Lake Titicaca“.

Frequency allocation 2GHz Japan

Wolfram|Alpha understands latitude and longitude values. So you can do “frequency allocation 15GHz 75W 40N“.

Frequency allocation 15GHz 75W 40N

The next time you are setting up your own transmission device, you can be aware of what frequencies are available without encroaching on frequency bands.


Obviously, W|A has a huge database of this data, but unfortunately can’t understand some queries that might be of interest to the readers of this article.

For instance, don’t you think that before publishing this article, you could have checked Wolfram|Alpha’s response to “What is the frequency of CB radios in japan?” –the query is totally misinterpreted and I couldn’t find a way to make W|A understand it.

Same for baby monitors in the us. ๐Ÿ™

I don’t mean to nitpick, but this just underscores the problem W|A is supposed to solve–too much data and not enough understanding.

Posted by reg.doug August 20, 2010 at 8:49 pm

The link to the BBC story doesn’t work.

Posted by wk August 20, 2010 at 11:00 pm

I tried “frequency allocation 802.11b” but no luck. That would be cool too — i.e. showing frequencies used by various IEEE specs, esp. around the world diffs.

Posted by David Sutherland August 23, 2010 at 10:02 pm

It would be helpful if we could have access tolfram Mathem ‘Help’ menu. It looks for instance as if the ‘Function Menu’ help would enable us to give input in a form guaranteed to be understood by WA.
Brian Gilbert, Volunteer Curator.

Posted by Brian Gilbert August 25, 2010 at 4:28 am

Typo in above comment – I was referring to ‘Wolfram Mathematica’ help menu.

Posted by Brian Gilbert August 25, 2010 at 4:30 am