How do I find the lack of radio waves?

July 17, 2008 6:06 AM

What town in the United States has the lowest amount of detectable radio waves?

Obviously, there are a lot of places (or used to be, anyway) where you can't get anything to come up on the radio dial. Which of those places would have the absolute least radio? As in, even though there are maybe hundreds of remote locations in the US (and let's say the continental US, because Alaska is probably the winner here anyway) where it's impossible to pick up anything listenable, would there be any place where there wasn't any radio that could even be detected?

Is there even a way to find this out?

Even better, is there any way to find out what the answer would have been in 1970? 1980?

I'm thinking mainly commercial AM/FM radio, and I don't even have a clue how to start looking into this. I figured that if anybody could help me figure it out, it'd be the metafilter crowd. If you need more information about what I'm looking for before you can help, I'd be glad to offer what I can. This is research for a project I'm working on, and although it's not vital it's a detail I'd like to be able to incorporate.

posted by mdbell79 to science & nature (16 comments total)

Radio astronomers will probably know. Maybe check this list of radio telescopes in the US?
posted by aramaic at 6:16 AM on July 17, 2008

Here's a Google Map of radio telescopes and radio quiet zones in the Americas.
posted by steef at 6:18 AM on July 17, 2008

Part of the problem is a question of the quality of radio—a little handheld AM/FM receiver might not get a signal in plenty of places where a car radio (with its big antenna), or a home station with a big wire antenna, would have a signal.

You might be interested in the National Radio Quiet Zone. There also exist similar things in "Puerto Rico, Desecheo, Mona, Vieques, and Culebra" (on account of Arecibo) and the "Table Mountain Radio Receiving Zone, Boulder County, Colorado." (I'd never heard of the latter.)

However, that doesn't mean that there's a total lack of radio signals; it seems probable, in fact, that there still may exist FM transmitters. The linked page says the "National Radio Quiet Zone" went into effect in 1958.

Is this for something like a novel, or is this a scientific research paper? The FCC should have somewhere on their site (apparently not the Wireless page?) a searchable database of every AM/FM transmitter in the country, which you could then plot on a map. This would most likely be painstaking, though. (Although, frankly, an interesting product to see!)
posted by fogster at 6:27 AM on July 17, 2008

In my experiences driving all over the country, only one area didn't have a single bleep on any segment of either band - eastern Utah, south from Hanksville. We literally *manually* tuned in to every spot on both am and fm and got absolutely nothing.

I've read that Natural Bridges NM is the least light-polluted spot in the country, so it would kinda figure that the least radio pollution would be nearby.
posted by notsnot at 6:30 AM on July 17, 2008

Figures, I find the link as soon as I post...

AM Query at the FCC Media Bureau, and FM Query... Though then we run into the problem that there are a ton of radio stations, many of them either incredibly low-power or just plain inactive, which won't be immediately obvious from the listing.
posted by fogster at 6:33 AM on July 17, 2008

Youre asking two very different questions. Places with low radio transmission or places with low AM/FM transmissions. As you can see from this frequency chart FM radio is a very small slice of the pie. You may find a place that doesnt have much commercial radio but is soaking in other UHV, VHF, SHF, and EHF transmissions.
posted by damn dirty ape at 6:38 AM on July 17, 2008

Also, ironically, when youre in the boonies you might find that there's more large transmitters near your head because places without wired infrastructures have a lot more CB, HAM, emergency services, navigation aids, etc via wireless.
posted by damn dirty ape at 6:41 AM on July 17, 2008

Yes, Fogster, this is for a novel. Just started a second draft, and I got curious about maybe moving a character who's obsessed with detecting a certain "radio" transmission to somewhere that would be otherwise completely consumed by static.

The National Radio Quiet Zone might work pretty well, actually-- I'll have to read more about it. Thanks for the link!

Notsnot, Utah would work pretty well for the book, as a large chunk of it takes place in that part of the country anyway.

Damn dirty ape, I'm sort of aware of that, but I think what I need "story-wise" is an empty radio dial from one end to the other, and if I can have it drastically so, then great, but if I just have to pick somewhere in the boonies that's fine too.

Thanks for all the early help, guys! There are a lot of places to start looking that you've suggested that I never would have thought of. It's much appreciated.
posted by mdbell79 at 6:54 AM on July 17, 2008

Speaking of the National Radio Free Zones, there was an article in Wired about the West Virginia zone. I've spent some time in the zone and while it can suck (very little cell coverage from only a few providers and only while on top of the tallest mountain in the area), it certainly isn't radio free as the article points out. Lots of stuff bleeds into the zone from outside of the zone and of course there is all the unlicensed RF that by definition the powers that be are unable to police.

As for places that are completely radio silent, I would look for geographic features that block radio waves like being underground or somewhere like the Zion Narrows.
posted by mmascolino at 6:57 AM on July 17, 2008 [1 favorite has favorites]

Green bank, West Virginia. We're in the center of the NRQZ. As you will probably read in the article, we have staff members who actively hunt down radio transmissions and stop them.

The funny thing is that even though there are no radio stations for a normal radio to pick up here, we can see radio stations in every slot in the FM band (and likely AM and TV too) with even a moderately large telescope and off the shelf spectrum analyzer. On the GBT, we could listen to every TV channel in the country. That is, if they weren't all piled on top of each other in the spectrum.

If you want more information on the NRQZ or the National Radio Astronomy Observatory, send me a message. I do work here, after all.
posted by kiltedtaco at 7:15 AM on July 17, 2008 [5 favorites has favorites]

Lots of places are devoid of local signals. Few places are so radio quiet that commercial AM stations can't be detected after sundown. Under about 10 MHz, you can pick up stations from around the world.

The commercial AM band at night always yields intermittently detectable signals.

FM... not so much. A really good antenna, with a rotator and a sensitive receiver can get you a few hundred miles of line-of-sight listening for a powerful station, in mono.

TV? Has AM and FM components, (and a phase modulated component, too) but the frequency is VHF/UHF and there are propogation issues that vary depending on atmospheric conditions. I've gotten Mexican TV transmission in Western NC before, actually on UHF. Something called tropospheric tunnelling was apparently involved and it was the 1970's. Could have been related to the solar sunspot cycles.

Generally, though, I'd have to go with the truly empty spots and mountainous valley areas, such as the secluded Rockies or Alaska.

( Hell, if it's a novel, why not just invent such a place? )
posted by FauxScot at 8:26 AM on July 17, 2008

Hah, kiltedtaco just inspired me to invent a Radio Hunters TV show, which will be much better than either COPS or The Deadliest Catch.
posted by rhizome at 8:44 AM on July 17, 2008

If you're interested in ad-hoc stories, my dial will spin through the FM spectrum without catching anything just NW of Red Lake, MN.
posted by unixrat at 9:42 AM on July 17, 2008

steef, that map shows several locations in New Mexico where I have had no trouble tuning in commercial FM stations.

mdbell79, I think you might want to read up a bit on radio waves, the US broadcast spectrum, and shortwave radio before you write your story. Here´s a bit on radio bands to get you started. People I´ve met that are obsessed with radio tend to have radios that get more than just AM and FM.

Years ago I drove from Lakeview, OR to Winnemucca, NV and found that I could not tune in any AM or FM stations. I don´t know if that would still be true of that area, or if a better antenna would bring some in. At the time I just wished for a cassette player.
posted by yohko at 2:56 PM on July 17, 2008

Oh, and there are several caves where you won´t be able to get any radio in the conventional sense at all.
posted by yohko at 2:58 PM on July 17, 2008

Although I can't answer your question, I recommend talking to Lisa Parks in the Film and Media department at UC Santa Barbara. I just heard her give a talk on wireless footprints in Mongolia.
posted by billtron at 12:53 PM on August 15, 2008