Military Transmissions On My Television?

[Native Son]

My brother called me to the basement last night to check out our television. It was about midnight. Our television was on channel 4 and it supposed to be on channel 116 for our satellite box. Anyway, we were listening to voices on channel 4...and we were hearing a radio transmission during a firefight. My brother was sure because he's just spent the last six years of life overseas in the airborne infantry fighting. He picked out the muzzle fire of a .50 caliber and other crap.

I thought it was just some other television program over the air we were picking up. But for five minutes we heard no narration, just the same guys operating their radio's during the firefight. Then we lost the transmission.

Radio waves can be reflected off the ionosphere but this would have to be very low frequency for it propagate half way across the world....

Maybe my satellite dish was picking something up, but that doesn't make any sense to me either.

 

[Urwumpe]

I think you should better learn how satellite TV works. Nice idea, but the hoax doesn't work out.

The frequencies of satellite TV are never reflected off the ionosphere, they are in the worst case bend a bit (needing 70 km more to reach you).

Also, satellite TV uses a different media access scheme as modern military short range radio (frequency multiplex vs code multiplex). What ever it received - it was more likely "Band of Brothers" as a real transmission.

 

[Coolhand]

are you saying that it came through the satellite itself, or it was recieved on the tv's internal UHF tuner?

either way though...

I used to have an old stereo that picked up the old style local emergency service 2-ways, that was interesting. not possible these days because they use digital encypted 2 way radios.

 

[n122vu]

Had something similar happen about 10 years ago. Was at a friend's house one night and we picked up a transmission on his scanner. It was definitely military. We had the transmission for about half an hour. Sounded like a training mission, but there was mention of one of the planes having an emergency with a light indicating that a cargo door was open mid-flight. We went outside and there were about 8-10 aircraft that flew just South of his house, heading East at high rates of speed (too close to each other and too low to be commercial aircraft).

 

[Native Son]

I'm sure it wasn't satellite TV...because it wasn't on the channel on my television that recieves the signal from my satellite box.

I asked my brother if the military actually uses unsecure transmissions at times and he said yes and minutely explained it in Army lingo. I have suspicions it was a training exercise somewhere in the country.

99% sure it was the internal UHF tuner. I don't think UHF can be reflected off the ionosphere because of its line of sight properties. So it could have been nearby....but I have no idea if I'm right on that.

Did some research on the channel 4 frequency and the audio carrier operates at 71.75 MHz....kind of low to be military.

 

[Urwumpe]

UHF has a pretty limited range, not further as about 50 km - it requires LOS.

During the last solar maximum, I received a radio station from Madrid on 95.1 MHz, which is VHF. About 2000 km away.

NTSC audio is compatible to VHF radio stations, so you can in theory receive audio transmission from quite some distance during solar active years (which we currently not have).

Also, I don't know about what the US military does, but German military radio equipment, which is NATO compatible, uses a basic frequency hopping encryption in combat regions.

The channels for military radio are also not used by German PAL TV, but US TV channels are assigned in the range - but I don't think, the 25 kHz steps between SINCGARS channels are fitting to the NTSC audio scheme. Have to calculate this.

http://en.wikipedia.org/wiki/SINCGARS

 

[ar81]

As a complete ignorant in this matter I came with some funny ideas...
-TV station is located near war zone.
-You are located near a war zone and you did not even know it (it means that the war is a fake and you see on TV is being filmed near your home)
-Your TV is capable of decoding encrypted communications.
-Due to doppler effect military frequency changed. Lower frequency means that war is travelling away from you. If you find the change in frequency you may estimate relative velocity of the war.
-You listened the enemy on TV (enemy does not use encoded equipment).
-You listened bank robbers.
-You listened an interference, another movie that is being passed in a channel adjacent to that one.
-You are having allucinations...
-It is a glitch in the matrix?
-You dreamed on it
-You are daydreaming
-You imagined it.
-Military made a mistake. They used non encrypted communication and a frequency that bounce back in the ionosphere.

 

[Zatnikitelman]

It is entirely possible to receive any sort of transmission through the TV. Particularly the HF transmissions that can be bounced off the Ionosphere. It's not really the tuner picking them up so much as some wire or something is the right length to resonate and carry the information to the speakers. There are a few other variables, but for the most part it could actually happen.

 

[simonpro]

My old television when I was at uni used to get screwed up every time a plane flew over. The radar transponder was on a frequency that messed with some of the internal electronics, stupid thing.

 

[Bullethead]

I'm not up on how current military radios and satellite TV work. I can say, however, that during in my time in the service (86-94) it WAS possible for military radio and civilian TV to interfere with each other.

In those days, the military's standard radio for ground troops was the PRC-77, which worked between 32 and 75 MHz. The upper end of this range overlapped with the lower end of broadcast analog TV, at least for audio. Thus, military radios could pick up the audio of TV channels 2 through at least 4. I figure this worked both ways, but never tested it.

Us troopies took frequent advantage of this. We'd usually come in from a field exercise about noon on Sunday and would have to spend the rest of the day cleaning and stowing our gear. The local football team's games were broadcast on TV channel 4, so we'd turn one of our radios to whatever frequency its audio came in on (something like 72.35MHz) and listen to the game as we worked.

BTW, it's extremely unlikely that you'd ever hear a long, continuous transmission from any military source. All radio operators are trained to talk in short bursts of only a couple seconds, so as to prevent the enemy's direction finders from locking in on them. Thus, if they have to say a long sentence, they break it up into segments of a couple words each with gaps in between. OTOH, officers are usually ignorant of this, so have been known to drone on and thus get their position shelled. Seen that happen. Moral to the story: never let an officer talk on your radio

 

[Urwumpe]

Moral to the story: never let an officer talk on your radio

Fits to my experience. Radio gear is too important to leave it in the hands of officers.

 

[Bullethead]

Fits to my experience. Radio gear is too important to leave it in the hands of officers.

Never let them have a map or compass, either, unless you enjoy them leading you out into an impact area .

 

[willy88]

That reminds me, a couple years ago, I had these speakers that tended to pick up radio transmissions. I think there was also one time when the picked up a police radio. They would go "BZZZ CRACKLE POP BZZZ", and I would have to turn them off so I wouldn't go deaf. Weird. :blink:

 

[Urwumpe]

Never let them have a map or compass, either, unless you enjoy them leading you out into an impact area .

Thank god, this fate never happened to me. But this lesson in basic training was fun. They give you a compass and a rough set of directions you should walk... and they you look where the soldiers go to. :lol:

You can't believe how hard it must be to move 250m in 3200 mils direction. Only a minority of the recruits reached the intended location.

You should generally never give an officer something, you might need yourself in the next years. Especially, don't lend them your excavation tool. You don't want to even imagine what a officer might do with it. Sure not digging a fox hole.

 

[Andy44]

I have heard citizens' band transmissions (CB radio) through my stereo before, but only when there was a really strong transmitter nearby. There used to be a guy living about a block away from me who had a big honking CB antenna hanging from his tree, and he would blast RF energy around the neighborhood. I could hear him talking through my stereo speakers. It's not there anymore, I presume someone complained and the cops or the FCC made him take it down, as he was certainly violating some rule or other.

 

[Danny Ramone]

It's not really the tuner picking them up so much as some wire or something is the right length to resonate and carry the information to the speakers.

Got it in one, when using un-encrypted analog radio waves the speakers themselves can sometimes translate the RF energy to actual sound. This happens to me all the time when testing radios at work before taking them out somewhere.

BTW HF waves do refract through the ionisphere, however these are becoming more and more redundant in Military communications. Most rear links are now high bandwidth satelite data applications.

In those days, the military's standard radio for ground troops was the PRC-77, which worked between 32 and 75 MHz. The upper end of this range overlapped with the lower end of broadcast analog TV, at least for audio. Thus, military radios could pick up the audio of TV channels 2 through at least 4. I figure this worked both ways, but never tested it.

This is still very similar these days, though the U.S military now mainly use the PRC-117. 32-512 MHZ. I'm guessing for emergency reasons, Military radios are built to TX/RX well outside their allocated range. Most military VHF is from 30-80ish Mhz. It allows allot of freedom and sometimes soldiers can use frequencies that they are not authorized to use.

I asked my brother if the military actually uses unsecure transmissions at times and he said yes and minutely explained it in Army lingo. I have suspicions it was a training exercise somewhere in the country.

It was most likely a training exercise, secure isnt used as often as most people think, as there is a risk of the codes being intercepted and analysed. Most encryption comes from frequency hoping and splitting (the PRR's split the transmission up and broadcast it over multiple frequencies simultaneously, this would mean you are less likely to intercept it with a normal radio)

My two cents anyway, sorry if its all over the place, its late and Im tired.

 

[Bullethead]

This is still very similar these days, though the U.S military now mainly use the PRC-117. 32-512 MHZ. I'm guessing for emergency reasons, Military radios are built to TX/RX well outside their allocated range. Most military VHF is from 30-80ish Mhz. It allows allot of freedom and sometimes soldiers can use frequencies that they are not authorized to use.

I wonder, come 9 Feb 09, whether troops stateside will still be able to receive TV broadcasts. That's when broadcast TV in this country will go 100% digital. Of course, I'm sure today's military radios are digital already. They were going that way when I was getting out of the service, but we were still 99% analog back then.

It's interesting that the new radio goes to such a high frequency. In my day, we thought anything above about 50MHz was useless for field operations. This was because these freqs apparently relied a lot on the ionosphere, which is only there in daylight. So during the day, we could talk 10-15 miles, but a night only like 1 or 2 miles using the direct wave. I was in the artillery where we had units spread out many miles apart, so this was a major problem. Thus, we always wanted to use freqs in the 30-40MHz range.

Problem is, we had no control of what freq we used. Every radio net for every unit in an entire division had a daily assigned frequency in a little book. Some brainiac had drawn this up to make sure all the division's units operating in the same area wouldn't interfere with each other. Problem is, he didn't take into account that some units never had to talk very far, while others did.

But anyway, radio does some strange things. We used to say that FM stood for "fing magic", because even if you knew what you were doing, sometimes the things wouldn't work, or sometimes would work when you knew they shouldn't. It always seemed more art than science. IMHO, there's really no telling where radio signals will end up, due to all the invisible things that affect them in the local environment.

 

[Danny Ramone]

PM sent to avoid going off topic