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If the sauce is not too blue

I've always wondered if the Mt. Elden Lookout Tower with all those radio, cell, and TV transmitters clustered so tightly around it was a very healthy place to be hanging out. Well, apparently it's not because yesterday I noticed that this scary looking notice had gone up sometime since my last Elden hike three weeks ago:

The jpeg's a little blurry so here's the text:

CAUTION

RADIO FREQUENCY ENVIRONMENT AREA

Authorized personnel only beyond this point! Radio frequency emissions at this site may exceed the federal occupational controlled exposure limits.

Personnel proceeding beyond this point must obey all posted signs, site guidelines and Federal Regulations for working in radio frequency environments.

Pretty scary stuff. The sign pretty much screams out Stay the Hell Away!

Well, inquiring minds wanted to know more. Some googling quickly turned up the FCC's Office of Engineering and Technology Radio Frequency Safety web site. It's filled with all sorts of interesting rocket science stuff like RF fields, Non-Ionizing Radiation, and Effective Radiating Power (ERP). The most applicable document appears to be Information On Human Exposure To Radiofrequency Fields From Cellular and PCS Radio Transmitters which has information on the maximum allowed microwatts per square centimeter from different transmitter types and powers. It seems to go well out of its way to reassure the reader that the amount of RF radiation you're likely to be exposed to at ground level under the average cellular base station is very low and not dangerous.

The picture changes a bit if you're not at ground level. From the document:

[...] Calculations corresponding to a "worst-case" situation (all transmitters operating simultaneously and continuously at the maximum licensed power) show that in order to be exposed to levels near the FCC's limits for cellular frequencies, an individual would essentially have to remain in the main transmitting beam (at the height of the antenna) and within a few feet from the antenna. [...]

[...] When cellular and PCS antennas are mounted at rooftop locations it is possible that RF levels greater than 1 µW/cm2 could be present on the rooftop itself. This might become an issue if the rooftop were accessible to maintenance personnel or others. However, exposures approaching or exceeding the safety guidelines are only likely to be encountered very close to and directly in front of the antennas. Even if RF levels were to be higher than desirable on a rooftop, appropriate restrictions could be placed on access.

I've emphasized the important pieces. Bottom line: if you're spending a lot of time up there at the same level as the transmitters then you're likely going to be exposed to potentially unsafe levels of RF radiation. This goes a long ways towards explaining why you hardly ever see anyone from the Forest Service manning the Elden Lookout tower and why the entrance is always locked, even when there is someone up there.

Here's a picture of the Elden Lookout complex with the Forest Service lookout tower just visible behind the tallest structure in the center:

The lookout tower isn't directly behind the transmitters but it's close enough. And there are a LOT of transmitters and receivers and who-the-hell-knows-what-all clustered around there.

Will I stop hiking Elden Lookout because of this? No. Will I forgo eating my energy bar on the cement block just down the hill from the transmitters? Probably!

By the way - did anyone get the obscure 80's reference in this post's title? Extra nostalgia points if you didn't have to google for it!

Moon in conjunction with Venus

Someone on Twitter just said I should go outside NOW and see the conjunction of the Moon and Venus. There were some thin clouds over to the west so this was the best picture I could get:

Very cool!

Vending machine for crows

What you're looking at is Jushua Klein's vending machine for crows. He got interested in crow intelligence and how they have adapted to live and thrive in a human dominated environment. If you follow the link there's a ten minute TED video where Joshua explains how and why he built the vending machine. It's very entertaining and fascinating. Be sure to read the comment threads after the video as well. Also, there's a project overview page at Joshua's web site.

While this is cool and all I hope it doesn't encourage other, maybe less science-minded individuals to try to take advantage of these birds.

Waiting for the worms

Ever gotten a song stuck in your head and couldn't get it out? You know, you hear a stupid commercial jingle or a kids' song and then it starts endlessly repeating over and over inside your head. No matter what you do it just keeps going on and on until inexplicably, hours later, it stops. Well, it turns out that those maddening recursive tunes and the phenomena of replaying them endlessly in your head have a name: earworms and there's a research website devoted to them (click image or here to go there):

I'm really glad they don't actually have live examples of earworms on the site. That would probably be a disservice to site visitors because, like the big red button labeled "do not click this button" you know you'd have to listen.

The last time I got it bad was at Disney Land a couple years back with a friend. [Now there's a place for earworms; that place is the freakin' magic kingdom of earworms.] It was the theme song for the big Main Street USA parade and I got it really stuck. It was just a few lines of catchy lyrics and repetitive bass track and afterwards I was spinning that damned thing around and around for hours. It wasn't even the whole song because I couldn't remember the end -- which probably contributed to it getting stuck in the first place. If I'd been able to run the thing through to completion it probably wouldn't have infected me. The little bit that I could remember would run right back to the beginning, making an infinite recursive loop.

In Alfred Bester's SciFi classic The Demolished Man the lead character Ben Reich uses an earworm to defeat telepathic cops. Because the cops can read minds they instantaneously know when you've committed a crime. By purposely infecting himself with an earworm he was able to conceal his thoughts. Great book if you're into SciFi and proto-cyberpunk.

[ found via The Old New Thing blog ]

Slow Motion Lightning

I found this via Mike's Birding and Digiscoping blog:

As Mike said -- too cool not to share!

Mars in solar conjunction

For those not in the know, Mars is in solar conjunction right now. What this means is that between October 18th and 29th Mars will be behind the Sun from our perspective. Here are a couple of Home Planet screen shots that illustrate the move:

The first image is from September 29th and the second from today (October 20th). Unfortunately Home Planet drew Mars in front of the Sun but in reality it is behind it. In fact, Mars is not visible at all right now because the glare from the Sun obscures it. Only through the magic of astronomy software are we able to see what it would look like if the stars/planets were visible during the day.

From our perspective it looks like Mars has moved to the right across the ecliptic. What's really happening is that the Earth, being closer to the Sun and moving faster than Mars, is slowly catching up to the red planet. You can think of it as a couple of race cars moving around a big track with the Sun at the center.

This planetary configuration is especially interesting because while Mars is in conjunction radio communications with our robotic orbiters and surface rovers will be all but impossible! Everything will have to operate completely autonomously until Mars comes back out from behind the Sun!

Designing intelligent robots that can operate for weeks at a time without any guidance from the Earth is really hard. JPL has a great article on their Mars Rover Mission website explaining how they are dealing with the loss of communications. Very cool stuff and definitely worth checking out!

Trinity Site tour this weekend

I am become Death, the destroyer of worlds.

Dammit, I missed it again! I just noticed that this Saturday (10/7/06) the Trinity atomic bomb test site will be open for one of its twice-yearly tours (first Saturdays of April and October). I won't be able to attend but I'm putting the April tour in my calendar so maybe I'll make that one. I think it would make for a fun overnight road trip.

Anyone interested in the trinity site should read Joshua Ellis's 'Dark Miracle'. Hell, read it even if you're not interested in the old nuke tests - it's a great article.

Oh, and while we're talking about nuclear tests, check out these freaky pics of some bomb detonations taken nano-seconds before the mushroom clouds form. According to the article the strange mottled shapes are caused by density variations in the bomb cases and the tower guide wires. Looks like something right out of Hell to me! Truly strange stuff!