Why am I hearing Letterman on 49.66125MHz?

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KD7HGK

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I'm hearing the Letterman TV show here in Knoxville. I've got a GRE PSR 500 scanner with a Radioshack 36 inch mag mount antenna. The signal starts to show up on 49.65 and peaks in clarity and strength on 49.66125MHz where I can understand if perfectly with only a little bit of static. Is this an image? or does somebody have a 49MHz baby monitor in the area that's picking up the show in their house and is rebroadcasting it? I can tune this frequency in the morning and hear nothing. Oh, and the scanner seems to think the signal has a CTCSS tone of 118.8 but when I apply that tone, it mutes the audio. I have to run no tone to hear anything.
 

kruser

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I'm hearing the Letterman TV show here in Knoxville. I've got a GRE PSR 500 scanner with a Radioshack 36 inch mag mount antenna. The signal starts to show up on 49.65 and peaks in clarity and strength on 49.66125MHz where I can understand if perfectly with only a little bit of static. Is this an image? or does somebody have a 49MHz baby monitor in the area that's picking up the show in their house and is rebroadcasting it? I can tune this frequency in the morning and hear nothing. Oh, and the scanner seems to think the signal has a CTCSS tone of 118.8 but when I apply that tone, it mutes the audio. I have to run no tone to hear anything.

Figuring most TV is now digital (especially the stations that broadcast Letterman) should rule out an image from the station itself. It could be an image from your local cable system though as they still convert back to analog in most areas.

I think the idea of a baby monitor is the likely reason.
 

kruser

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It is a baby monitor...how close are your neighbors?

Did they even make baby monitors that used the channels added after the initial 5 channels were authorized? The originals were 49.830, 845, 860, 875 and 890. For some reason I thought baby monitors were never allowed outside the original set of five 49 MHz frequencies.

I do still agree on a baby monitor regardless.
 

Gator596

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One of the many models of wireless headphones that were marketed and sold for watching TV without disturbing a bedmate could be another explanation.
 

kruser

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One of the many models of wireless headphones that were marketed and sold for watching TV without disturbing a bedmate could be another explanation.

Now that you mention that, the kid that lived behind me played computer games a lot. He had an amplifier with a powered subwoofer that shook the whole building at 3 AM even though he did not have the overall volume set very loud at all. Just a tad bit much on the bass!

After the people below him called the police once too many times, he bought some kind of device that did broadcast his game or movie audio over a wireless device of some type.
That broadcast was around the same freq as the OP mentioned.
Anotherwords, it was below the original five cordless phone frequencies that most baby monitors used.
I found it one night when doing a scan with a spectrum analyzer.
It pegged the analyzer and the signal was wideband FM plus the center frequency was centered above a normal freguency just like the OP's Letterman show frequency was listed.
I never did ask the kid who made the thing but then he stopped using it. I wish he still used it though as he does get carried away some nights when he does his gaming. Lucky for me, his subwoofer is on the floor aiming down but I can still feel the vibrations sometimes.

I bet you are correct and this is what the OP is hearing!
 

krokus

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In addition to the post-Letterman, what do you hear pre-Letterman?
 

KD7HGK

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In addition to the post-Letterman, what do you hear pre-Letterman?

I didn't have my scanner on before I heard Letterman. I also don't hear anything right now on that frequency except a constant carrier, sounds like static and is full strength.
 

KD7HGK

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Did they even make baby monitors that used the channels added after the initial 5 channels were authorized? The originals were 49.830, 845, 860, 875 and 890. For some reason I thought baby monitors were never allowed outside the original set of five 49 MHz frequencies.

I do still agree on a baby monitor regardless.

I tuned those frequencies and actually managed to pick up a full strength carrier on 49.830MHz. I can hear a very low volume woman's voice talking but I can't quite make out what she's saying.
 

jfhtm350

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44mhz home cordless phones operate from 48.600 to 49.990. Those are the first cordless phones to come out I believe and there are not very many left around I would say. There are many other devices that use these same frequencies. It is pretty much a free for all for alot of wireless devices such as remote control cars and probably that earpiece you can hear tv with and not disturb your wife. Now they just need to make a button to go over her mouth to mute her. Hehe.
 
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