How Is This Possible???

Flyingcursor · Post by **Flyingcursor** » Fri Dec 17, 2004 10:21 am

When I was a kid our neighbor, a ham radio guy, used to cut in on my Dad's amplifier and say hello now and then.

Sunnywindo · Post by **Sunnywindo** » Fri Dec 17, 2004 1:36 pm

That bounce stuff is so cool! I didn't realize the fun to be had (and this explains why I sometimes get great channels and other times they don't want to come in at all). I wonder though, if my little mystery isn't someones leaky sattellite and not true bounce. Bounce sounded like it's more likely to happen on the lower channels and my station is coming in on channel 58. And the length of time for which it appears to have been (and continues to) happen makes me wonder as well.

Or maybe, it really is a Utah thing! After all, I can't imagine the Crystal People being all that interested in ///*&^%#@/// szzzzz.....

Sara (signing off from the Twilight Zone... AKA "Sara's kitchen")

TomB · Post by **TomB** » Fri Dec 17, 2004 2:12 pm

raindog1970 wrote:Atmospheric disturbances sometimes have amazing effects on radio and television transmissions.
Back in the 1980's I was hooked on sideband radios... I never had a legitimate HAM license, and never knew anyone else who did either!
When sunspot activity was high, or around the time of an equinox, it was always interesting to see how far away you could talk... ah yes, back in the good old days before the Internet!
I also remember one time years ago when I turned on my home stereo and could only pick up Oriental music... even the local stations were drowned out!
It only lasted for a few minutes before everything returned to normal, but it's something that I'll always remember... it's very rare for an incident that powerful to take place.

The reason for this bounce, and it happens with AM radio fairly often, is because of the frequencies and the Ionosphere. This is the layer that when the sun hits it, many of the atoms lose their electrons and turn into ions. As luck would have it, the ionosphere also happens to reflect certain frequencies of radio waves. The ionosphere is different during the day then it is at night, (but then, are most ??). The composition of the ionosphere is different at night because of the absence of the sun. So, as it turns out, during the night certain radio frequencies, particularly AM, will bounce back and forth between the ground and the ionosphere, sometimes for hundreds and hundreds of miles. Then, as the sun comes up, the ionosphere resorts back to its daytime persona, so the radio waves don't get bounced liked at night.

As someone already mentioned, Sunspot activity can play havoc on radio transmissions.

I'm not sure if this is this stuff applies to television though, but since someone mentioned radio, I thought that I would chime in.

All the Best, Tom

Darwin · Post by **Darwin** » Fri Dec 17, 2004 2:39 pm

TomB wrote:[The reason for this bounce, and it happens with AM radio fairly often, is because of the frequencies and the Ionosphere. This is the layer that when the sun hits it, many of the atoms lose their electrons and turn into ions. As luck would have it, the ionosphere also happens to reflect certain frequencies of radio waves. The ionosphere is different during the day then it is at night, (but then, are most ??). The composition of the ionosphere is different at night because of the absence of the sun. So, as it turns out, during the night certain radio frequencies, particularly AM, will bounce back and forth between the ground and the ionosphere, sometimes for hundreds and hundreds of miles. Then, as the sun comes up, the ionosphere resorts back to its daytime persona, so the radio waves don't get bounced liked at night.

As someone already mentioned, Sunspot activity can play havoc on radio transmissions.

I'm not sure if this is this stuff applies to television though, but since someone mentioned radio, I thought that I would chime in.

TV is more in the FM range, isn't it? When I was in the 5th grade, before we got our first TV set (before I'd ever even seen one, in fact), we lived down near the Rio Grande Valley, and I could pick up a TV station on the FM radio.

If I recall correctly from my granddaughter's physics homework, FM frequencies are much shorter than AM. (I recall almost nothing from my own physics homework--or even from the little bit of theory I learned 22 years ago to get my Ham novice license.

)

Regarding picking up radio on odd things, my Mac speakers pick up some (local?) radio station at night. When the computer is on, you can barely hear it, but when I turn the Mac off, it comes in loud and clear for a couple of seconds, like there is a residual charge of some kind in the speakers, then it fades away.

TomB · Post by **TomB** » Fri Dec 17, 2004 2:51 pm

[quote="Darwin[/quote]

TV is more in the FM range, isn't it? When I was in the 5th grade, before we got our first TV set (before I'd ever even seen one, in fact), we lived down near the Rio Grande Valley, and I could pick up a TV station on the FM radio.

If I recall correctly from my granddaughter's physics homework, FM frequencies are much shorter than AM. (I recall almost nothing from my own physics homework--or even from the little bit of theory I learned 22 years ago to get my Ham novice license.

)

Regarding picking up radio on odd things, my Mac speakers pick up some (local?) radio station at night. When the computer is on, you can barely hear it, but when I turn the Mac off, it comes in loud and clear for a couple of seconds, like there is a residual charge of some kind in the speakers, then it fades away.[/quote]

Yes, you are correct. The FM broadcast frequencies are sandwiched between two sets of TV broadcast frequencies. These groups of frequencies are not particularly close to the AM frequency range.

You are also correct when you say that they are shorter. The higher the frequency, the shorter the wave.

All the Best, Tom

Steven · Post by **Steven** » Fri Dec 17, 2004 2:59 pm

Darwin wrote:TV is more in the FM range, isn't it? When I was in the 5th grade, before we got our first TV set (before I'd ever even seen one, in fact), we lived down near the Rio Grande Valley, and I could pick up a TV station on the FM radio.

If I recall correctly from my granddaughter's physics homework, FM frequencies are much shorter than AM. (I recall almost nothing from my own physics homework--or even from the little bit of theory I learned 22 years ago to get my Ham novice license. )

TV is actually beyond the FM range, in the VHF (Very High Frequency) and UHF (Ultra High Frequency) range. This is a considerably shorter wavelengh than radio waves, but nowhere near as short as visible light. As I recall, lo these many years since school, radio waves have wavelenths in the range of feet to meters, TV in the range of millimeters to centimeters. The longer radio waves are a lot more likely to bounce off the ionosphere. (By comparison, the wavelengths of visible light are from around 400 to 700 nanometers, where a nanometer is a millionth of a millimeter.)

Or I could be remembering all or part of this completely wrong and just making a complete fool of myself. One or the other.

Steven

RonKiley · Post by **RonKiley** » Fri Dec 17, 2004 5:35 pm

Skip occurs on high frequencies when the sunspot cycle is high. I don't know what part of the cycle we are in now. The distance involved depends on the frequency. You may be at the "perfect" distance for this station. I have talked with people in south america on less than 100 watts of power on a frequency of just above 28 megahertz. When I lived in Rhode Island I used to talk with people in New York on a frequency not far from the channel 58 frequency. There are also other strange phenomena such as tunneling or ducting where a wave will travel between two atmosperic layers to distances far greater than usually possible. Of course we are talking about Utah here strange things are not unusual. My grandchildren in school there report strange things all the time.

Ron

OutOfBreath · Post by **OutOfBreath** » Sat Dec 18, 2004 9:14 pm

susnfx wrote:Maybe it's Utah, Sara. When I was a teenager growing up in southern Utah we couldn't get radio stations from Salt Lake City or even Las Vegas. For years the only rock station we could pick up was KOMA in Oklahoma City. Clear as a bell. Every night (not during the day). Go figure.

Susan

Yep, that was my station in southwestern Colorado, too. One of the reasons you could only pick it up at night is because at night certain AM radio stations are allowed to increase their output power as other stations
go off the air.

In the early 80's I was in the Air Force stationed in Altus Oklahoma and I had a warskil AFSC as a cop so I had to pull cop duty 3 days a month. I always volunteered for the night shift 'cause it was cooler. So one night I'm on gate duty with one of the regular SPs and I said, hey, we should be able to pickup KOMA now! He gave me a funny look but tuned to 1520 (funny how some things stick in your mind) anyway. It was a trucker / country / talk station. I was severly disappointed!

Wombat · Post by **Wombat** » Sun Dec 19, 2004 9:40 am

This stuff also has to do with such banal factors as the power of the transmitter and presence or absence of natural obstacles. Driving around in country Australia, I can often get clear AM signals from 1,000 miles away or further but might not be able to get anything from a nearby station. Driving through mountains, I have to keep changing stations to get the same program. As I round a mountain, the station that I was receiving cuts out and another cuts in. Wollongong is a long thin city built between a mountain range and the sea. There are two TV transmitters in the city. Some people can get both, some one and some neither. Some people can also get Sydney channels. I heard it said in New Zealand that, on a clear night, it is possible to get Sydney television on the west coast. I've never confirmed this for myself.

In the US in the 50s, there were very powerful transmitters just over the border in Mexico that could be picked up clearly in Chicago. I suppose these stations were getting around some law but I'm not sure of the details.

When I lived in England, in one house I could pick up both a local taxi company and, if I remember correctly, the police on my stereo.

pearl grey · Post by **pearl grey** » Sun Dec 19, 2004 10:56 am

Darwin wrote:If I recall correctly from my granddaughter's physics homework...

You have a granddaughter! And a granddaughter old enough to study physics, no less! I always think of you as the young man in your picture, even though I know it's not you.

A few weeks ago, my computer speakers picked up a man talking (on a CB I guess). And no, it wasn't just a popup ad on the computer. And when I turned the volume all the way down on my speakers, he was still coming in loud and clear! It was creepy, so I just turned the speakers OFF.

Now baby monitors, THAT'S the way to pick up all kinds of weird things!

Darwin · Post by **Darwin** » Sun Dec 19, 2004 3:36 pm

Wombat wrote:In the US in the 50s, there were very powerful transmitters just over the border in Mexico that could be picked up clearly in Chicago. I suppose these stations were getting around some law but I'm not sure of the details.

At leat part of the story can be found at http://www.ominous-valve.com/xerf.html.

Darwin · Post by **Darwin** » Sun Dec 19, 2004 3:54 pm

Hmm. Duplicates can't be deleted unless they're the last post?

Darwin · Post by **Darwin** » Sun Dec 19, 2004 3:55 pm

pearl grey wrote:
Darwin wrote:If I recall correctly from my granddaughter's physics homework...
You have a granddaughter! And a granddaughter old enough to study physics, no less! I always think of you as the young man in your picture, even though I know it's not you.

Well, it was me. However, I've reverted to a more up-to-date rendition, just to avoid confusion.

dubhlinn · Post by **dubhlinn** » Sun Dec 19, 2004 3:59 pm

Darwin wrote:
pearl grey wrote:
Darwin wrote:If I recall correctly from my granddaughter's physics homework...
You have a granddaughter! And a granddaughter old enough to study physics, no less! I always think of you as the young man in your picture, even though I know it's not you.
Well, it was me. However, I've reverted to a more up-to-date rendition, just to avoid confusion.

Nice Avatar - if somewhat Spooky!

Slan,
D.

Charlene · Post by **Charlene** » Mon Dec 20, 2004 9:29 am

One of our local Spokane TV stations comes in on FM at the very first FM station you can tune to. They even advertise that. Gives me an appreciation for how frustrating it must be for my blind friend when without the picture there's no way you know what's going on just from the sound.

And sometimes at night, especially if I go west of town and up out of the valley we are in, I can pick up a Vancouver BC radio station - but not Seattle, which is closer.