HD-RADAR

On Sun, 01 Jul 2007 15:21:40 -0400, Del Mibbler [email protected] wrote:

Sam Spade wrote (in part):

The NEXRAD radar I pull off www.nws.noaa.gov vary from 5 to 15 minutes,
depending upon the site.

I wonder why a television station would be concerned about that delay?

As others noted, sometimes a few minutes delay can make a
life-or-death difference. But I think stations want their own radar
for much the same reason they want their own meteorologists reporting
the weather. I remember when a station's weatherman was just a guy
who read the NOAA forecast, often dressed in a uniform advertising
Texaco or whatever company sponsored that segment. Then one station
hired a meteorologist (who emphasized, "MY forecast is . . .") and
suddenly they alll had to have one.

One station in my area ran ads promoting their Doppler radar showing
people carrying models of the radar tower around with them at work, on
picnics, etc. The tag line was something like, "We bought Doppler
radar so you don't have to."

Another station put a continuous feed of their radar on a digital
subchannel; local cable also carries it. But due to unexpected
consequences of ill-conceived FCC regs, they've decided to keep the
OTA viewers from seeing it. It's still broadcast so that cable can
get it (cable gets a direct feed of the same signal sent to the
transmitter) but it's marked "hidden" in the digital bitstream. My
computer-based tuners can still get it because they already knew how.
If I do a rescan I'll lose it.


Our local (WJRT 12-2) still has it on digital SD with 24 hour
forecasting included. (Bay City, Saginaw, flint MI) Normally they run
the RADAR interspersed with forecasting.

That radar is quite handy and seems to be real-time. I check it
before going for a walk, and I work with satellite equipment that's
affected by rain, so it's good to know when we'll get hit and when it
will let up.

Del Mibbler

On Sun, 1 Jul 2007 03:13:46 -0400, "Captain Midnight"
wrote:

wrote in message
...
On Fri, 29 Jun 2007 20:09:41 -0400 Captain Midnight
wrote:

| Local CBS affiliate, WHIO-DT(Dayton,OH), just gave a sneak peek of their
new
| HD Doppler radar. The stations news only went 16:9 a month or so ago,
IIRC.
| According to them they'll be the first in the nation to use the new
radar.
| The very brief preview looked like Doppler radar meets Google Earth.
That's
| all I know about it so can't answer questions. Looked really good but
have
| no idea how much more useful it will be.

So they make the radar look "cool" by adding a bunch of "ground clutter"?
I'd prefer a solid background and radar system that displays all
combinations
of attenuation, vector velocity, as well as cloud top heights. All of
that
combined can be rather intense and using some sort of topology as the
background would really just end up being more intrusive. I always turn
topo off for radar I get online (I get it where it can be turned off).


You have an opinion about something you've never seen? I turn off topo on

I run the terraine and find it useful Then again I'm usually talking
to a number of people out there trying to stay out of trouble.

On Mon, 2 Jul 2007 21:45:15 -0500, "David Moran"
wrote:


"Roger (K8RI)" wrote in message
.. .
On 1 Jul 2007 02:36:40 GMT, wrote:

On Sat, 30 Jun 2007 19:07:33 -0500 David Moran
wrote:
|
| wrote in message
| ...
| On Sat, 30 Jun 2007 10:26:12 -0500 David Moran
| wrote:
| |
| | "Sam Spade" wrote in message
| | ...
| |I can't believe any of these television stations are actually
erecting
| |doppler radar sites. Those things cost a fortune to buy, erect, and
| |maintain. And, the government runs a whole bunch of them called
NEXRAD
| and
| |offer the feeds to all of us gratis.
| |
| | As a meteorologist myself, the thing is that by the time the NEXRAD
data
| can
| | get to everyone, it can be 10-15 minutes old. Most stations buy their
| own
| | radar because they get faster updates.
|
| They can get their own raw feed from the NOAA NEXRAD directly and
process
| it themselves into video. I would think that is cheaper. It's real
time
| since the raw feed is the serialized reflection data in the direction
the
| radar is currently pointing.
|
| While I am not a television meteorologist, I'm only telling you what my
| television counterparts tell me. They've mainly complained that by the
time
| they get NEXRAD data, it's 10-15 minutes old.

They must be getting it from a second source supplier which calls it
NEXRAD data (because it probably is NEXRAD data).

The best you can hope for in true NEXRAD is about 5 minutes.
I can't remember if this has been mentioned, but NEXRAD is the name of the
network of radars, not the individual radars themselves.

Although it is a network of individual stations that can present a
mosaic of the national scope the NEXt generation RADar (NEXRAD) is
also capable of each site generating a fully independent image for the
area it covers ( OTOH it might be more correct to say an image can be
generated for each individual site.) so the acronym is used
interchangeably to describe the RADAR site (WSR-88D) as well as the
system.



Dave

On Mon, 2 Jul 2007 22:56:07 -0400, "Captain Midnight"
wrote:

"ValveJob" wrote in message
.. .
On Sun, 1 Jul 2007 03:40:31 -0400, "Captain Midnight"
wrote:

"jiml" wrote in message
.. .
On Fri, 29 Jun 2007 20:09:41 -0400, "Captain Midnight"
wrote:

Our CBS station in Houston does all the news and weather in HD. From
my vantage point, I see the doppler in HD, so don't really care
whether it comes off the radar box that way.


I know the news in HD isn't all that new. I'm talking about the RADAR.
Does
the RADAR you see look like Google Earth?

http://www.whiotv.com/weather/13580217/detail.html

Unfortunately no pics or video of the output.


All Radar, by definition, is extremely low def. Seeing it in HD
adds little, if any. Instead, they should focus on improving the
studio cameras that better portray the cute little ass on the weather
girl.


Could be but haven't seen any weather on it so can't comment. The map on the
other hand is better. If you've used mapping software you no that higher
resolution and bigger screen means you can show a bigger area with more
detail. If nothing else they can show more detail at a farther distance. It
has a 200 mile range. Kind of impressive just watching it sweep across a
little bit of Lake Michigan and a good bit more of Lake Erie. Showing where
the weathers at Should also be more accurate.

Well, I'm a sucker for anything HD. I'll swith local news coverage
again in a heartbeat if the doppler hd is as good as you say.

On Mon, 02 Jul 2007 22:54:26 -0400 "Roger (K8RI)" wrote:

| As to "Real Time" when it pertains to NEXRAD the typical *processed*
| image contains data from sweeps that are near current to around 5
| minutes old. The "next generation" NEXRAD should cut that time
| substantially.

All these delays are inherint in the processing to produce an image AND
the distribution of that image. It can still be made much faster simply
by applying good design practices with that goal (images no more than 20
seconds old, for example). If you connect to the _raw_ feed and do your
own processing, you can get images a lot faster.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
|------------------------------------/-------------------------------------|

On 4 Jul 2007 05:22:14 GMT, wrote:

On Mon, 02 Jul 2007 22:54:26 -0400 "Roger (K8RI)" wrote:

| As to "Real Time" when it pertains to NEXRAD the typical *processed*
| image contains data from sweeps that are near current to around 5
| minutes old. The "next generation" NEXRAD should cut that time
| substantially.

All these delays are inherint in the processing to produce an image AND

No, all of the delays are not inherent in the processing. It takes
many sweeps combined to get that NEXRAD image. If you don't combine
all the sweeps and the information therein you can process it much
faster as could the NWS. You really need to combine the Doppler
information as well with a lot of other information and that is what
takes the time.

the distribution of that image. It can still be made much faster simply
by applying good design practices with that goal (images no more than 20
seconds old, for example). If you connect to the _raw_ feed and do your
own processing, you can get images a lot faster.

Yes, but don't confuse that with a NEXRAD image. You get the results
of a single scan converted into an image like we do with airborne
RADAR that shows reflection intensity based on the "base reflectivity"
which shows only the intensity of the reflection and distance. IOW it
only shows rainfall intensity. I've flown through deep red
reflections in a Beech Debonair/Bonanza and just washed the bugs off
the plane. It was a nice smooth ride. The reflections looked just like
the ones associated with severe thunder storms if taken out of
context. I've also watched the RADAR as we threaded our way through a
line of severe thunderstorms in a Kingair and that was not a smooth
ride. The reflections looked much the same in both cases and required
a pretty good background to interpret.

On Wed, 04 Jul 2007 19:36:27 -0400 "Roger (K8RI)" wrote:
| On 4 Jul 2007 05:22:14 GMT, wrote:
|
|On Mon, 02 Jul 2007 22:54:26 -0400 "Roger (K8RI)" wrote:
|
|| As to "Real Time" when it pertains to NEXRAD the typical *processed*
|| image contains data from sweeps that are near current to around 5
|| minutes old. The "next generation" NEXRAD should cut that time
|| substantially.
|
|All these delays are inherint in the processing to produce an image AND
|
| No, all of the delays are not inherent in the processing. It takes
| many sweeps combined to get that NEXRAD image. If you don't combine
| all the sweeps and the information therein you can process it much
| faster as could the NWS. You really need to combine the Doppler
| information as well with a lot of other information and that is what
| takes the time.

Those sweeps can be done a lot faster than five minutes. And if all
you want is reflection (attenuation) then one sweeps gives it to you.
Still, they can always be releasing updated info with each sweep based
on it and all the previous. It would be a group of sliding windows to
program it. It seems they don't do this.


|the distribution of that image. It can still be made much faster simply
|by applying good design practices with that goal (images no more than 20
|seconds old, for example). If you connect to the _raw_ feed and do your
|own processing, you can get images a lot faster.
|
| Yes, but don't confuse that with a NEXRAD image. You get the results
| of a single scan converted into an image like we do with airborne
| RADAR that shows reflection intensity based on the "base reflectivity"
| which shows only the intensity of the reflection and distance. IOW it
| only shows rainfall intensity. I've flown through deep red
| reflections in a Beech Debonair/Bonanza and just washed the bugs off
| the plane. It was a nice smooth ride. The reflections looked just like
| the ones associated with severe thunder storms if taken out of
| context. I've also watched the RADAR as we threaded our way through a
| line of severe thunderstorms in a Kingair and that was not a smooth
| ride. The reflections looked much the same in both cases and required
| a pretty good background to interpret.

There are several frequencies that can be used to get water and vapor
reflections. Do the bugs (and other flying things) always reflect at all
the same frequencies? Why not use multiple frequencies to verify it is
water?

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / |
|------------------------------------/-------------------------------------|