" So why Napa? Does every town have them? "

" sprklsunshine

we have a great "look angle" over the Pacific from here. And no; not every town has them. That is so easy to see from way up here... "

" Use of satellites for telephone communication is a common misconception. In fact, very little telephone (or internet, VoIP) communication is passed via satellite. The reason is time and cost. If you consider that the distance from Napa to Sydney (Australia) is roughly 18,000 miles via oceanic cable, and a satellite in geo-stationary orbit sits at about 22,600 miles from the surface, the distance to send that signal from an earth station in Napa, to a centrally positioned satellite, then down to an earth station in Sydney, that signal has traveled 45,200 miles one way. So, a two way conversation via satellite travels 90,400 miles round trip, versus 36,000 terrestrial.

Electrical and microwave signals travel at just shy of the speed of light. So, one might think that a 45,000 mile trip at that speed would be no big deal. However, the next time you are watching your favorite CNN or Fox News anchor in a live conversation with their correspondent in Bagdad, pay attention to the amount of time it take from the end of the question the anchor asks in New York, and when the correspondent begins to answer. You will notice a delay of two or three seconds as the correspondent is listening to the question.

If you have friends or family in Asia or Europe, and make international phone calls to them, you will notice that the delay between your statements and their responses are not as pronounced as those between the anchor and foreign correspondent on T.V. The reason is your phone conversation is terrestrial bound. The exception would be where a key circuit in the trans-oceanic cable is interrupted and the phone company is forced to route through satellite. Satellite time is also expensive. "

" Skip, are you trying to say "Electrical and microwave signals" are different ? Or should people believe that microwave signals are a subset of electrical (or electronic) signals. "

" Reason-ater: I was trying to simplify the discussion for the non-technical, while still making my point about the distance and communication issue. Microwave is used in satellite communication, where trans-oceanic cable has historically been more similar the type of electronic signal found in telephone lines in you house. The point being that microwave is a type of radio signal, where traditional cable transmits/conducts electrical impulses along a wire.

However, much of the trans-oceanic cable has been converted to fiber optic, which uses a form of laser, and actually does travel at the speed of light. Fiber optic also does not require the same level of filtering since there is no electro-magnetic bleed through that the more traditional electrical signal is subject to. "

" Skip, I'm not arguing with you at all. It's just very easy for non-technical people to think microwaves are a kitchen appliance.

But I do have a question about the electo-magnetic bleed in fiber-optic lines you referred to that requires less filtering. I always kinda assumed that traditional electronic signal needed to be filtered because of the harmonics and/or mixing products resulting from the signal generation. I'm guessing that the fiber-optic signal is digital and requires less filterering. But aren't the new 'traditional' communication signals also digital ? Or am I thinking about it the wrong way ? "

" Reason-ater: True, fiber-optic does use a digital signal, but the transmission medium is light, and that is what prevents the bleed through. Any electrical signal is subject to bleed over of adjacent signals. Cross talk is a form of this that one might experience with analog signals, but bleed through is not limited to crosstalk. Signal distortion or corruption is another factor.

Digital signals are resistant to cross talk, but are still subject to distortion. If you computer network cables are run too closely to power lines, you may notice loss or distortion of signal in your network. This is due to the bleed through from the power lines. This same thing can happen in trans-oceanic cables.

Power is sent along communication lines to support amplifiers along the path of the signal. An example of this is the 24 volts AC that is in your phone line. If you touch the two leads of your telephone wire, you will get a little zap. Where there is electron flow, you will have a magnetic field. Where there is a magnetic field, you will have electron flow. This is at the heart of signal bleed. If the signal is digital or analog, it is all electron flow in traditional copper or aluminum wire. "

" man its like a contest here to see who can quote wikipedia on signal transmission the fastest. *pops bag of popcorn* *pulls up comfy chair* I eagerly await more riveting dialogue! "

" Sorry, no wikipedia quotes here. Just 20 years experience in the business. "