Long story short, I know this guy that worries about the wrong things. Latest example was tonight as we were walking to the bar and we passed a direct TV dish and he made a wide arc around it claiming he “didn’t want to exposed to the waves coming from it.”
Ok, never mind that the dish is just the receiver, and never mind those frequencies aren’t harmful. How powerful are the satellite transmismitters and what kind of power is bathing us all on the ground at northern Arkansas latitudes? Also, what kind of gain do direct TV dishes have/what kind of power would you be subjected to if you put your hand at the focus?
The fact that they need a dish to capture the signal is an indication of how weak the signal is.
The gain on those dishes is around 33 db, or over 1,000 times a regular dipole antenna. So, assuming the receiver is about as sensitive as a cell phone, the TV signal is many hundreds of times weaker.
Speaking of cel phones, what kind of power are they transmitting/recieving these days, inches from your crotch? A couple watts? Even that seems high to me.
From a Ham radio discussion board:
“Maximum possible power output of a handheld cellular phone is 0.6 watts.
Like others have posted, the system controls the actual output of the phone and it is typicially much less than that, usually less than 100 milliwatts.”
Also, the signal being received by the satellite dish isn’t just there at that spot. It’s literally everywhere, so making a wide arc around the satellite dish isn’t somehow protecting the worried friend.
Of course, if it is a satellite internet dish, it is transmitting. When I hit “Post Quick Reply”, this message will be transmitted to a receiver around 2,800 miles to the southwest and 22,000 miles to the up of me. (Don’t tell me that I’m not living in the future!)
Yeah, I told him that first. His reply is that sunlight is natural and humans evolved with it. :smack: the fact that sunlight has been shown to increase your cancer risk doesn’t bother him for some reason.
Yeaaaaaah. As Dewey Finn noted, we’re continously getting “bombarded” by radio waves from hundreds of communications satellites; the satellites are not specficially pointed only at the satellite dishes (it’s the reverse, in fact). The guy has no bloody clue what he’s talking about.
I used the word bathed rather than bombarded, but yeah. He’s generally a bright guy and funny. Just isn’t technical at all and has weird health quirks.
It sounds like he’s worried that the dish is concentrating the signal. Which it is, but only at the focal point, and even there the signal is so weak it needs to be amplified by a co-located preamp called a low noise block amplifier (LNB) just so it can make it through the cable into the receiver in the house. The reason for the dish, IOW, is to raise an extremely weak signal above the limits of detectability. Your friend is a nut!