Radar data via digital, over-the-air free TV

sebenste

EF1
Joined
Dec 17, 2005
Messages
71
Location
Chicago, IL
Hey gang,

There is something you should know...many TV stations in the Plains
will be broadcasting high-resolution radar data for free! 24/7/365.
You see them late at night when you crash at hotels and see local doppler,
satellite, etc. Well, you can get it for free while on the road!

Some people have TV's in their cars to monitor local stations coverage.
Some have TV tuners via a TV tuner card in their laptop. Here's the deal...
If all goes well, in February 2009, your tuner card and analog TV will show nothing but snow. The FCC has mandated that all TV stations transition from analog to digital. That's been under way for several years, but by July 1 of this year, ALL digital TV stations have to be at full power unless they show hardship (serious tower, construction or land permit issues).

If you have an analog TV hooked up to an antenna, you will only see snow on a channel showing a digital broadcast. But if you have a digital tuner card on a PC, or a set-top box, or a TV that has a built-in digital tuner, you will see crystal-clear broadcasts of what they are showing on their analog station (IE, what you see on satellite or cable, or a regular TV hooked up to an antenna).

BUT, the beauty of digital TV is that you can do something known as "multicast". Each digital TV station has 19.3 megabits/sec of data they can use to show a TV program. But the latest technology lets you break that digital stream into multiple channels! In Oklahoma City, 3 stations have a main channel. But the NBC affiliate has a "subchannel", as they are called, showing NBC Weather Plus 24 hours a day. And, the FOX TV station has a channel showing nothing but radar, satellite and current conditions 24 hours a day! You don't need to have an HDTV to view these....just a digital tuner:

http://ruel.net/pc/tv.tuner.links.htm#hdtvcards

A lineup of Oklahoma stations is here:

http://www.hdtvok.org/mod.php?mod=userpage&page_id=3

and at http://www.hdtvok.org for the rest of the state.

Notice on the above Web site that KOCO-DT has weather on channel "5.2". When your tuner
locks on to a station, the station "remaps" the channel number.
Even though they broadcast physically on channel 7, data in the digital stream changes the output on-screen to show channels 5-1 or 5-2 (read aloud as "five dot two" or "five dash two"). KOKH-DT has it on 25-2, and KFOR-DT has it on 27-2.

In Chicago, WMAQ-DT 5.2 and WLS-DT 7.3 broadcast all weather and live radar almost continuously. In Rockford, IL, radar is found on WREX-DT 13.2. Milwaukee, 10-4 through 10-6 has it, and soon, 4-2.

Digital TV reception is a bit problematic. The signals do go out further, due to the digital and signal steam design. I am exactly 60 miles west of Chicago's broadcast towers, low in a river valley, and have my antennas in a one-story townhome. I can easily get all but one channel; the latter is
at low power. But, when driving, the picture can break up, especially if you are farther away from the tower. If you have a good tuner with a signal amplifier from the car roof antenna, you can get full-power stations 60 miles or more out in the Plains.

All you need to buy is:

An antenna for your car roof (or keep it inside, but get poorer reception)

Cable to go down to your tuner

A digital tuner card in your PC or a separate set-top box for your existing TV

Maybe a signal amplifier (good idea)

And then scan for channels until you find one with weather!

The primary channel used for the major networks broadcasts in HD during largely primetime hours and major sports events, but even if you don't have an HDTV, you can watch the show in "letterboxed" format, with black bars at the top and bottom of the screen as the image is shrunk so you can see everything. Regardless, once you get the tuner card, antenna and lead-in cable to your tuner, you are done. When you scan for stations, look for "-2" and "-3" channels, and at least one or two will show all weather. No subscription fees, period. A cheap and good
option if you are on the road this year.
 
I have heard of this anolog to digital switch, and with this also happening to cellphones. Does anyone know when we won't get an analog signal with our cell phones? I'm not looking forward to that day because allot of remote areas are still not cover with digital when analog does.
 
Originally posted by Robert Edmonds
I have heard of this anolog to digital switch, and with this also happening to cellphones. Does anyone know when we won't get an analog signal with our cell phones? I'm not looking forward to that day because allot of remote areas are still not cover with digital when analog does.

Yeppers. Every tower has to be digital on or by January 1, 2009.
A month before the analog TV shutdown happens.

In many major cities, though, it's all digital already, of course.
On January 1 2006, you can't buy an analog or even dual-analog/digital cell phone in northern Illinois. All our towers are digital.
 
Yeah, I know that here in Minnesota, KARE 11 broadcasts live radar 24-7 on I think 11-2. You'll need an HD tuner but the radar image should be in HD which will make it more like a computer image then a fairly low-quality TV radar image. I think KELOLAND in South Dakota does similar.
 
Digital PCMCIA Tuner cards

Has anyone been able to find a digital/HDTV PCMCIA card?

I'm striking out looking for these.

brianb
N5ACN
 
Re: Digital PCMCIA Tuner cards

Has anyone been able to find a digital/HDTV PCMCIA card?

I'm striking out looking for these.

brianb
N5ACN

I have a Sharp Aquos with a PC card slot. Is that what that's for....a digital/HD converter?

Also, my understanding was that the range on digital (mobile phones at least) was less than analog. The lower range was offset by the increase in quality.

What about driving around with a digital tv? Unlike analog, there is no such thing as static. You either get all the information or you don't. It seems like you would need some sort of a buffer. My satellite radio buffers the signal to reduce cut-outs under bridges, etc.
 
Re: Digital PCMCIA Tuner cards

My satellite radio buffers the signal to reduce cut-outs under bridges, etc.

How does it do that? If you lose the signal, you're going to lose the incoming information. Does it provide redundant streams for this kind of thing?

Tim
 
Re: Digital PCMCIA Tuner cards

My satellite radio buffers the signal to reduce cut-outs under bridges, etc.

How does it do that? If you lose the signal, you're going to lose the incoming information. Does it provide redundant streams for this kind of thing?

Tim

I'm guessing the radio buffer works the exact same as a CD player buffer. It delays the broadcast several seconds ahead and when you lose the signal you'll have a few more seconds of audio already in the buffer to play.
 
Re: Digital PCMCIA Tuner cards

My satellite radio buffers the signal to reduce cut-outs under bridges, etc.

How does it do that? If you lose the signal, you're going to lose the incoming information. Does it provide redundant streams for this kind of thing?

Tim

Ok, I'm assuming it does that. My only verification is that when I unplug the antenna I continue to have uninterrupted music for several seconds before it cuts out completely. The only explanation for this is some sort of a buffer, like modern portable cd players have. Hard drive based Ipod's also run a buffer, as well as my cd writer on my laptop.

It makes since, otherwise there would be constant drop-outs in the music. Like I said there is no such thing as static satellite radio. All the digital information has to be there or it wont work.
 
Re: Digital PCMCIA Tuner cards

My satellite radio buffers the signal to reduce cut-outs under bridges, etc.

How does it do that? If you lose the signal, you're going to lose the incoming information. Does it provide redundant streams for this kind of thing?

Tim

If we're talking about XM, there are generally two satellites in different parts of the sky at the same time. Both sats broadcast the full data stream; they're redundant. Each sat is slightly time delayed from the other (around a second, IIRC). The radios listen to both sats at the same time and buffer; generally, the radio uses the two streams to checksum each other. If you go under a bridge and one sat is blocked, the radio continues to play the buffered audio while it gathers data from the other satellite, which is not blocked by the bridge. I suspect WXWORKS works the same way.

There's a neat writeup about the various sat technologies here.
 
"If you go under a bridge and one sat is blocked, the radio continues to play the buffered audio while it gathers data from the other satellite"

There are 10 bridges I pass under on my way to/from work each day... For three of those bridges, I lose the audio about a second after passing under the bridge for maybe a half-second. Whether I'm going east>west or west<east and I can't see any other obstruction around which would block just one of the sats.
 
"If you go under a bridge and one sat is blocked, the radio continues to play the buffered audio while it gathers data from the other satellite"

There are 10 bridges I pass under on my way to/from work each day... For three of those bridges, I lose the audio about a second after passing under the bridge for maybe a half-second. Whether I'm going east>west or west<east and I can't see any other obstruction around which would block just one of the sats.

Beats me. The sats sit on the SE and SW horizons where you are. The further north you are, the farther down on the horizon they are. In Michigan, they should be pretty low, though not horribly so. When you pass under any bridge, both sats will, at some point, be obscured; the only time the "no dropouts" thing works is when at no point both sats are obscured at the exact same time.

If you want to have fun and see the signal strength for each satellite as you drive and you have a Delphi receiver, power down your unit (if you have it on), then press 2 then 0 then 7, then the XM button. It'll turn on. Once it's on and playing music, hit the display button a few times. Eventually you'll get to a bunch of debug menus. The first menu is cool -- the BER is the Bit Error Rate. Anything over 5% means that the signal from that satellite is too weak to be heard. The next menu has C/N, which is signal to noise. This can help you bigtime if you're trying to aim your home antenna. :)
 
Most Oklahoma HD'ers would rather have the weather channels dropped though
http://www.hdtvok.org/mod.php?mod=poll&op=...ts&pid=31&cid=0

Which is NUTS!!

I considered DFW's digital radar and weather feeds to be a valuable tool even before becoming a complete WXNERD.

Katrina proved it, this is just further evidence. Most people don't think about the 'what-ifs' of their existance.

A little better resolution for ER vs. real-time weather/emergency info?

Hmmm....tough choice....NOT!! </RANT>

brianb
N5ACN
 
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