# Mystery HAM radio signal! Any guesses? **URL:** \ **Category:** Factual Questions\ **Created:** [September 16, 2004, 8:15pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727 "2004-09-16T20:15:50Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [September 17, 2004, 12:56am UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/1 "2004-09-17T00:56:55Z")
[http://www.arrl.org/news/stories/2004/09/09/103/?nc=1](http://www.arrl.org/news/stories/2004/09/09/103/?nc=1) > [@](#): > > An unidentified signal that’s been showing up on the 40-meter phone band on or about 7238 kHz has mystified amateurs in the western US and Canada, where it’s been heard frequently for the past few weeks. Although it resembles a steady carrier, a closer inspection suggests that the intruding signal actually is a series of closely spaced signals. > > … > > While no one’s sure what it is, the FCC HF Direction Finding Facility has been able to determine that it’s coming from somewhere north of Prescott, Arizona, and west of Interstate 17. FCC monitoring indicates the “buzz” is centered on 7238.1 kHz with a bandwidth of about 1 kHz and spikes spaced at about 90 Hz apart. > > Reports to the International Amateur Radio Union Region 2 Monitoring System indicate the signal has been heard from about 1700 to 2130 UTC, although Moman reported hearing it at around 0300 UTC and said the signal even went off the air for a few seconds while he was listening to it. Neat. Any guesses as to what it is? Secret govt. tests? Those hippies in Sedona channelling some other-dimensional being? Everyone in Arizona using their microwaves to make lunch at the same time? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [September 16, 2004, 8:15pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/2 "2004-09-16T20:15:50Z")
Who makes lunch at five o’clock? 🙂 ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [September 16, 2004, 8:17pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/3 "2004-09-16T20:17:40Z")
Wow, my lame joke was so funny it seems to have gone back in time. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [September 16, 2004, 8:55pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/4 "2004-09-16T20:55:05Z")
Sorry–your lame joke also sent me several hours into the future, so that I temporarily couldn’t respond. Anyway, isn’t 1700-2130 UTC actually 10AM-2:30PM Arizona time? ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [September 17, 2004, 2:39am UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/5 "2004-09-17T02:39:29Z")
Seems to me that it wouldn’t be too hard for the military to triangulate in on the source of the signal and track down the folks responsible. Considering the paranoia people have of another terrorist attack, I’d say that if it were a threat, the military would have already shut it down. Which means, of course, that it’s a military project we’re not supposed to know anything about. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [September 17, 2004, 4:33am UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/6 "2004-09-17T04:33:45Z")
… in which case, by publishing the truth, you have sealed your fate. ---
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [September 18, 2004, 2:15pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/7 "2004-09-18T14:15:34Z")
> [@Tuckerfan](#): > > Seems to me that it wouldn’t be too hard for the military to triangulate in on the source of the signal and track down the folks responsible. Considering the paranoia people have of another terrorist attack, I’d say that if it were a threat, the military would have already shut it down. Which means, of course, that it’s a military project we’re not supposed to know anything about. Well, or it could just be some interference that’s annoying only to HAM operators, and not to the military. Not a threat, but an annoyance. And frankly, I think everyone’s trust that our military’s all-seeing eye knows everything that’s going on–or, even more to the point, that anyone in the military gives a rat’s ass about anything outside of their narrow job descriptions–is woefully mistaken. “Some buzz on that channel? Why should I care? Tell the HAMs to change channels.” ---
**Author:** ![dogbutler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dogbutler/32/428_2.png) [@dogbutler](https://boards.straightdope.com/u/dogbutler)\ **Post date:** [September 18, 2004, 5:43pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/8 "2004-09-18T17:43:20Z")
[tinfoilhat] 1920’s style mind control rays? [/tinfoilhat] ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 18, 2004, 6:07pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/9 "2004-09-18T18:07:38Z")
The signal has [stopped](http://www.arrl.org/news/stories/2004/09/17/3/?nc=1). There is a spectrogram of the signal on this page as well, for those curious about such things. It definitely does look like one or more subcarriers impressed on the main carrier. I wonder if anyone’s done a Fourier analysis on it? ---
**Author:** ![KP](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KP](https://boards.straightdope.com/u/KP)\ **Post date:** [September 18, 2004, 6:54pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/10 "2004-09-18T18:54:19Z")
Isn’t a spectrogram (power plotted in the prequency domain) a kind of Fourier Analysis? Excuse me if I’m being dense. I may have my foil cap on crooked. ---
**Author:** ![Tripler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripler/32/21807_2.png) [@Tripler](https://boards.straightdope.com/u/Tripler)\ **Post date:** [September 18, 2004, 7:01pm UTC](https://boards.straightdope.com/t/mystery-ham-radio-signal-any-guesses/264727/11 "2004-09-18T19:01:09Z")
I am a proud alumnus of the [Prescott, AZ](http://www.erau.edu/pr/index.html) area, and am darn familiar with the area: Mingus Mountains, Camp Verde, Cottonwood, Sedona, etc. Now, put your tinfoil hats on for this one: “East of Prescott, AZ and I-17” puts you in the neighborhood of Camp Verde/Pine area. I have a weak, sneaky suspicion that one of the side harmonics from a _normal_ signal may be bouncing off a mountain in just the right way to cause this. Theres the Drake VOR up north of town, multiple radio antennae on local mountains themselves, etc. The clincher for me: the area is known for gold and copper in the mountains, and gold follows black, iron oxide sand. My point? Iron and copper in the rock _may_ be the perfect ground plane/reflector for signals. The geograpgy in the area may be perfect enough that it scatters everything to the stratosphere where everyone gets a piece of the pie. I know it’s weak, but it’s my gut reaction. I left a lot of my theory books at work, so I’ll have to do a little digging and geeking out on Monday to substantiate it, but I present my thoughts for your opinion. Tripler But, I am totally open to your thoughts, guys! I’m just a local resource.