I just watched a storm develop from just light rain to nasty boomer on
the radar (and pass over my house) in seven minutes, which leads me to
wonder whether, had I been relying on Nexrad for strategic weather
avoidance, I might have flown right into it, and whether sferics would
have given me a better heads-up.

Given a choice, and noting that you usually can get a radar loop before
takeoff, which would you prefer installed in your simgle-engine IFR
bugsmasher? (The choice is between sferics and downloaded Nexrad images)
I wonder if sferics is still the better choice, given it's real time,
no subscription, and lightning is reported to precede rain by
significant time.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Sferics would have definitely been better, had you been in an airplane.
Sferics are real-time...when there is a discharge, you see it immediately.
NEXRAD, as available today, has a built-in delay of from 4 to 11 minutes.
The folks at the NWS sites can see the results of each antenna rotation
incrementally, but the "whole picture" is made up of many rotations, at
different elevations, and must be massaged before being transmitted to user
ports.

Bob Gardner

"Jose" > wrote in message
m...
>I just watched a storm develop from just light rain to nasty boomer on the
>radar (and pass over my house) in seven minutes, which leads me to wonder
>whether, had I been relying on Nexrad for strategic weather avoidance, I
>might have flown right into it, and whether sferics would have given me a
>better heads-up.
>
> Given a choice, and noting that you usually can get a radar loop before
> takeoff, which would you prefer installed in your simgle-engine IFR
> bugsmasher? (The choice is between sferics and downloaded Nexrad images) I
> wonder if sferics is still the better choice, given it's real time, no
> subscription, and lightning is reported to precede rain by significant
> time.
>
> Jose
> --
> The monkey turns the crank and thinks he's making the music.
> for Email, make the obvious change in the address.

Viperdoc wrote:
> I have both, along with active radar. The Nexrad gives a better all around
> picture, while sferics requires some interpretation. For the money, Nexrad
> download is a better choice.

Agree. I have sferics and XM nexrad. If I had to choose, I'd take the nexrad,
for the same reasons Viperdoc mentions. I concede the real-time nature of the
sferics vs. delayed nexrad, but nexrad is still the better tradeoff. Both is best.

"Jose" wrote:

>I just watched a storm develop from just light rain to nasty boomer on the
>radar (and pass over my house) in seven minutes, which leads me to wonder
>whether, had I been relying on Nexrad for strategic weather avoidance, I
>might have flown right into it, and whether sferics would have given me a
>better heads-up.
>
> Given a choice, and noting that you usually can get a radar loop before
> takeoff, which would you prefer installed in your simgle-engine IFR
> bugsmasher? (The choice is between sferics and downloaded Nexrad images)

I just returned from a 2-day trip to s. Texas, during which I used NEXRAD to
weave in and out among air mass CBs. I would NOT have wanted to do this
with spherics alone, as it simply does not give a clear enough "big picture"
for me to be comfortable with such tactics. Would I like to have a
Stormscope as well? Sure. Have to choose one? NEXRAD, hands down.

> I wonder if sferics is still the better choice, given it's real time, no
> subscription, and lightning is reported to precede rain by significant
> time.

Nice to have, but inferior *overall* to NEXRAD link, IMO. The
no-subscription feature is a real point in its favor, though.

--
Dan
C172RG at BFM

In article >,
"Dan Luke" > wrote:
> > I wonder if sferics is still the better choice, given it's real time, no
> > subscription, and lightning is reported to precede rain by significant
> > time.
>
> Nice to have, but inferior *overall* to NEXRAD link, IMO. The
> no-subscription feature is a real point in its favor, though.


It depends on what information you desire. I have a StrikeFinder and
XM. The StrikeFinder is infinitely better at identifying lightning.
The StrikeFinder can also help identify serious convective activity, but
then again, so can NEXRAD + Echo Tops. No way would I rely on the XM
products for lightning detection, but I didn't have a StrikeFinder, I
probably wouldn't put one in. Flying with both is optimal, but there is
substantially more information provided via XM.


JKG

> The StrikeFinder can also help identify serious convective activity, but
> then again, so can NEXRAD + Echo Tops.

.... except Nexrad is at least seven minutes old, and sometimes fifteen.
What prompted the question was watching hearing boomers out my window,
and seeing that Nexrad had only light rain showing. On the next update,
seven minutes later, some moderate rain was showing. Meanwhile, it was
thunder and lightning outside my window.

I'd've been unhappy in the air.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Both strike finders and NEXTRAD have strong and weak points. The
strike finder is real time. Even at the weather station the newest
image is about 5 minutes old. The strike finder will not show you the
beginnings of convective activity while the RADAR *may*.

With time you learn to anticipate, or forecast using NEXTRAD but it
takes watching it for a while as well. If you know what it's been
doing, where it's going, and it's history along with moisture, laps
rate, and lifting index you can do well in predicting 5 to 10 minutes
ahead, but don't expect to pinpoint specifically what's going to be
happening where, when.

With study and experience the two together are fantastic and I wish I
had them in the Deb.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"Jose" wrote:

>> The StrikeFinder can also help identify serious convective activity, but
>> then again, so can NEXRAD + Echo Tops.
>
> ... except Nexrad is at least seven minutes old, and sometimes fifteen.
> What prompted the question was watching hearing boomers out my window, and
> seeing that Nexrad had only light rain showing. On the next update, seven
> minutes later, some moderate rain was showing. Meanwhile, it was thunder
> and lightning outside my window.
>
> I'd've been unhappy in the air.

In practice, it doesn't seem to matter much.

The lag has not caused any problems for me in two years of regular XM Wx use
in thunderstorm country.

As with all things in flying, judgment and experience make the difference in
using linked NEXRAD safely.

--
Dan
C172RG at BFM

In article >,
Jose > wrote:

> > The StrikeFinder can also help identify serious convective activity, but
> > then again, so can NEXRAD + Echo Tops.
>
> ... except Nexrad is at least seven minutes old, and sometimes fifteen.
> What prompted the question was watching hearing boomers out my window,
> and seeing that Nexrad had only light rain showing. On the next update,
> seven minutes later, some moderate rain was showing. Meanwhile, it was
> thunder and lightning outside my window.


NEXRAD can be a couple minutes old, or up to several minutes old
(assuming you receive the 5 minute updates.) It isn't "at least seven
minutes old." However, you have no idea HOW old it is, so I certainly
wouldn't use it to navigate around thunderstorms unless I was VMC.



JKG

Viperdoc wrote:
> The Nexrad gives a better all around
> picture, while sferics requires some interpretation.

I agree - I've used both. The sferics requires a lot of interpretation
- and few pilots have the skill set to use it to maximum effect. There
is a long learning curve. However, once the learning curve is
complete, the real time nature of the sferics makes it superior for
tactical operations - those where you get within about 25 miles of the
activity. The nexrad is clearly the superior strategic tool. However,
for strategic purposes Fligh****ch makes an acceptable substitute.

> For the money, Nexrad download is a better choice.

For the average pilot, I agree. For someone who will take the time to
really learn how to use the sferics for tactical avoidance (more time
than he will ever save over simply taking longer detours around weather
or occasionally landing to wait it out), and will use Fligh****ch to
make up for the strategic deficiencies of sferics, the sferics is
better.

Of course both is best.

Michael

> The sferics requires a lot of interpretation
> - and few pilots have the skill set to use it to maximum effect.

What are the kinds of things involved in this interpretation? Could you
give me a few examples?

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Jose wrote:
> > The sferics requires a lot of interpretation
> > - and few pilots have the skill set to use it to maximum effect.
>
> What are the kinds of things involved in this interpretation? Could you
> give me a few examples?

I can give you individual examples, but that won't give you a useful
understanding of how to do it.

Example:

The distance to the strikes is very approximate - however, you can
estimate the distance quite accurately by monitoring how long it takes
a radial to spread. For example: You're doing 90 kts, and in 5
minutes the dots go from showing up at your 1 o'clock position to your
1:30 (15 degree shift). That's 3 degrees per minute, and you're doing
1.5 miles per minute, so the distance from you to the cell is actually
30 miles. That can be pretty imprtant if you are expecting a right
turn sometime soon.

Example:

Not all strikes are created equal. The stormscope sees static
discharges, of which lightning is just one flavor. Generally,
lightning strikes will show as more than one dot, all along one radial
line. With time, you get pretty good at separating out real convective
activity from the light turbulence.

Example:

When approaching a line perpendicularly, the point just ahead of you
will look like the weakest spot. This is because that radial takes the
shortest path through the line. When approaching, you need to make
some heading changes to see where the real weak spots are, by comparing
the way the screen populates with dots.

To properly describe all the issues involved would take a book - or at
least a long article.

Michael

> I can give you individual examples

Thanks, they were illustriative.

> To properly describe all the issues involved would take a book - or at
> least a long article.

It would probably be a =very= useful long article. You could post it as
a series. In fact, I wonder if Jay's website might be a good place to
put such things...

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

In article >,
Peter > wrote:
> >NEXRAD can be a couple minutes old, or up to several minutes old
> >(assuming you receive the 5 minute updates.) It isn't "at least seven
> >minutes old." However, you have no idea HOW old it is, so I certainly
> >wouldn't use it to navigate around thunderstorms unless I was VMC.
>
> In that case, why have it at all. In VMC, one doesn't need radar to
> avoid the stuff.


Because you have no idea what's up ahead, and whether or not you need to
divert now, or will be able to complete your flight.


JKG

There are several ways of getting the Nexrad. But the best way is how
Garmin is doing it, using the XMradio satellite radio channel. It is
quite good. Just as in GPS, satellites are a superior way for ground
and airbased vehicles to get their position data and any other data
(highway traffic for cars etc) they need. At any rate the XMradio is a
great solution for this sort of thing.

Peter,

> What is the worldwide coverage like with XM?
>

Nil. There are two geostationary satellites covering the western and
eastern US, aptly named "Rock" and "Roll" (XM does music radio,
primarily). The frequencies used are allocated to military/public
services in much of Europe, for example, so don't hold your breath on
an international expansion.

--
Thomas Borchert (EDDH)

Peter,

> Thomas, are you aware of any service which can be used for airborne
> data - other than the full TCP/IP thing from say Iridium?

Inmarsat offers a service, I think. Connexion by Boeing works with
Inmarsat, too. And Iridium, as you say.

> I believe there is a data service run by Ericsson, on the back of
> their GSM network or something like that.

GSM wouldn't work. The antennas don't receive from higher altitudes
(above, say, 3000 feet).


--
Thomas Borchert (EDDH)

> > Thomas, are you aware of any service which can be used for airborne
> > data - other than the full TCP/IP thing from say Iridium?

> Inmarsat offers a service, I think. Connexion by Boeing works with
> Inmarsat, too. And Iridium, as you say.

Article in todays Wall Street Journal.... Boeing is dumping the
Connexion business.

Boeing to Shutter Connexion
As Web Service Failed to Catch On
By J. LYNN LUNSFORD
August 18, 2006
In a setback for efforts to make Internet service widely available to
air travelers, Boeing Co. threw in the towel on its Connexion in-flight
Internet venture, saying it plans to shut down the unprofitable
six-year-old service by year's end.
Boeing acknowledged in June that it was in talks with
commercial-satellite operators and other potential suitors, but it also
hinted strongly that it might abandon the business altogether. The
satellite operators concluded that there was too much risk in buying
Connexion outright, a person familiar with the situation said.

In a statement, Boeing Chairman and Chief Executive Jim McNerney said:
"Regrettably, the market for this service has not materialized as had
been expected. We believe this decision best balances the long-term
interests of all parties with a stake in Connexion by Boeing."
Boeing's experience with Connexion underscores how difficult it has been
for companies to find a profitable way to keep passengers connected to
the ground, even though such ability would enable business travelers to
be more productive. Many airlines that might have been customers appear
to be leaning toward a much-cheaper technology with less capacity that
relies on traditional cellular networks, but even those fledgling
projects aren't without financial and technical challenges.
Boeing said it plans to take a charge of as much as $320 million, or 26
cents a share, to cover the costs of shutting the service. About $290
million of that will be taken in the third quarter and the balance in
the fourth. The company previously estimated that the potential charge
could be as much as $350 million. Beginning next year, the company said,
it expects a benefit of about 15 cents a share to reflect the
discontinued investment in Connexion.
The U.S. unit of Luxembourg's SES Global SA -- a supplier of satellite
capacity for Connexion -- confirmed that it had been in discussions with
Boeing about possibly taking over the service, but after months of
discussions no agreement was reached. Monica Morgan, a spokeswoman for
the unit, declined to elaborate.
Annual revenue for the unit from Boeing's onboard Internet service is
less than $25 million, according to industry officials. But Ms. Morgan
said SES also has booked about $300 million in its order backlog related
to Connexion. She said Boeing and SES are in talks about phasing out the
service, and what penalties Boeing will have to pay for canceling
long-term leases of satellite capacity. SES declined to discuss details
of those talks.
Boeing said it expected that most of the 560 employees of Connexion
would be moved to jobs within Boeing. It said it would work with
customers to begin an orderly shutdown of the service. In addition to a
handful of international airlines, Connexion is used on several U.S.
government planes, including Air Force One. A company spokesman said
that Boeing plans to honor its contracts with the government until a
solution can be worked out.
The service is available on select long-haul flights by a handful of
airlines, including Lufthansa, Japan Airlines, Singapore Airlines and
others. A Boeing spokesman said that even on those flights, the usage
rate among passengers was "in the low single digits." Boeing has never
said how much it invested in Connexion, but people familiar with the
venture put the figure at about $1 billion.
Mr. McNerney, who took over as chairman, president and chief executive
of Boeing just over a year ago, made it clear that he wasn't as enamored
as his predecessors were with Boeing's foray outside of its core
businesses. This year, Mr. McNerney gave the first outward signal that
changes were afoot when he removed the Connexion unit from reporting
directly to his office and put it under the oversight of the company's
director of mergers and acquisitions.
--Andy Pasztor contributed to this article.

> Article in todays Wall Street Journal.... Boeing is dumping the
> Connexion business.

IF we won't be able to carry laptops and cellphones and PDAs in the
cabin, Connexion is toast anyway.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.