WX-900: First Impressions (Long)
Gregory R. Travis
are some first impressions. I've not had a chance to "test" it in any
real weather, but as soon as I do I'll post a followup.
Choices: BFG WX-900 StormScope vs. Insight StrikeFinder
Street Prices: $3500.00 for the WX-900, $4500.00 for the StrikeFinder
$8000-11,000. for the WX-1000/1000+
Installation runs $300-$500 depending on what has to happen. The WX-1000/1000+
have a separate black box. The StrikeFinder and WX-900 have all their
electronics in the display.
What I found out:
Ryan/3M/BFG/Foster StormScopes:
Very little real information is available about the "Series II"
technology that the WX-900/WX-1000/WX-1000+ units from BFG/Foster use.
BFG/Foster bought the StormScope series from 3M which had bought the
ORIGINAL StormScope technology (which no one seems to refer to as "Series I")
from Paul Ryan, the inventor of the StormScope.
However, the ORIGINAL "Series I" stormscopes basically work this way:
An assumption is made that all lightning is created equal. Thus distance
to a strike is simply a function of the strength of the received signal.
The bearing to the strike is determined with conventional ADF methods. The
bearing and estimated distance is then plotted on a screen. Bingo.
This method obviously suffers from its assumption that all lightning is
basically the same. This assumption causes what's known as "radial
spread" on older "Series I" StormScopes. Because a given thunderstorm
will have many strikes of varying intensity, it is plotted on the screen
as being closer and deeper than it really is. In other words, the weak
strikes within the storm are plotted as being farther away than they really
are and the strong strikes are plotted as being closer than they really are.
The storm is shown like this: But it's really like this:
*
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** **
*
I I
===== =====
I I
--- ---
(Images Copyright (C), 1992 Gregory R. Travis)
BFG claims that the "Series II" StormScopes have solved this problem, but
they don't hint at all as to how the "Series II" StormScopes do it. My
feeling is that the units remain basically analog. However, when my
WX-900 is powered up, one of the messages on the screen is "SW REV 1.21"
So there is a computer in there somewhere, and someone is revising the
software. But it may do nothing more than look after the analog parts.
Before I bought my unit, I rolled a C210 with a WX-1000 (Series II) out
on the ramp while a series of bad storms approached from the west.
We had clear skies, but could easily see a pretty big system about 100
miles west. Weather radar (via Weather Channel technology) confirmed the
system's location and intensity. Turned on the WX-1000 and, after a bit,
it began to clearly indicate the precise bearing and distance to the storm.
The dots were tightly clustered too with no stray dots on the screen. I was
suitably impressed.
Insight StrikeFinder
These are completely digital units, using a Digital Signal Processor chip.
I talked to a few people who gave me quite a lot of information on how
the units work. I'm sure to get the specifics wrong, but as I understand
it the unit "listens" for discharges like a StormScope. When it hears one,
it does a waveform comparison against ROM tables containing various "stock"
lightning waveforms. One person, who knew quite a bit about the specific
implementation, commented that "Texas lightning is different from Florida
lightning." I assume also that a relatively weak discharge has a different
characteristic waveform from that of a particularly strong waveform. Thus
it is possible to discern a weak strike close by from a strong strike farther
away. Using the information in its tables the StrikeFinder can,
according to Insight, make a MUCH better determination of the actual
distance to the strike. They claim that you will get a tighter clustering
of dots with the StrikeFinder.
The StrikeFinder filters out cloud-cloud discharges, the WX-900 as far
as I can tell does not.
Some considerations:
The WX-900 has only a 100 mile range. WX-1000 has a 200 mile range
The StrikeFinder can be slaved to an HSI, the WX-900 cannot.
The WX-1000+ ($10K) can.
The WX-900 is LCD, the StrikeFinder uses a plasma display.
The WX-900 is a little over 7 inches deep, the StrikeFinder over 10
inches. Check your panel space.
The WX-900 has a bus (voltage) monitor built in. Nice if you
don't already have a voltmeter.
BFG/Foster claim that, at 100NM range, the WX-900 actually does
a BETTER job of resolving weather than their higher-priced
(by a factor of two!) WX-1000 units at the same range setting.
They say this is because it does not have to worry about 200NM
range. Sounds silly to me though.
The WX-900 does not filter cloud-cloud discharges and will show
them along with cloud-ground. I consider this a plus, Insight
says it's a minus. With Insight's system if you see dots
you KNOW there is serious weather there. It seems that the WX-900
might alert you to lesser weather. Insight says it'll just
cry wolf more often. BFG disagrees.
It seems a lot of shops are much happier about BFG/Foster's support
and test equipment it seems. Many seem to like the StormScopes
because they are the "original."
The StrikeFinder has an animated replay feature. No one that I
have talked to has really used this feature. Seems like it might
be nice though.
BFG/Foster are currently suing Insight, claiming patent infringement.
Obviously BFG/Foster think that the Insigight technology is not
sufficiently different from their own. Both sides
expect victory :-)
I went ahead with the WX-900. I couldn't justify the extra $1000.00 for
the StrikeFinder in my little bird.
Observations:
The backlit LCD display is VERY nice. At night I feel like I'm
flying big iron with that green screen staring at me. It's not hard to
read at an angle (the LCD contrast is adjustable from the unit's menu).
It does wash out in bright light however.
I have a problem with my (electronic) flashing beacon. The shop warned me
that it was emitting a LOT of noise. I've always been able to hear it in
my headset as a periodic click with an accompanying constant whine.
With the beacon on the WX-900 starts to "paint" a severe storm 75 miles
directly behind me. My bird has strobes, DME, Transponder, and other
stuff and none of them cause any false strikes. If I turn off the beacon,
the screen completely clears in about 2 minutes. The shop says this is
a problem with the Cessna electronic beacon and they've seen it on a
number of airplanes. They don't know of a fix except to replace it with
a real rotating beacon. Any net.electronic wizards out there than can
suggest a less expensive fix?
I have no idea if the StrikeFinder would have the same problem.
Background (read if you need help justifying buying one):
I've wanted (needed) a storm detection system in my airplane for a while now.
It's fairly rare that we get IFR weather in the spring/summer/fall here in
the midwest without the CHANCE of thunderstorms along with the IFR conditions.
Like icing in the winter, forecasters almost always include the possiblity
of a thunderstorm with any adverse weather. Most of the time they don't
develop, or are far from your route of flight. The result is a lot of
nervous bumping along, trying to stay reasonably visual, in summer IMC.
I've scrubbed a lot of flights because of a chance of boomers along my route,
only to sit at home in front of the weather channel watching the storms
NOT materialize. And I've spent a lot of time slogging through rain, wondering
if the next bump was going to be that thunderstorm that the briefer said
had a "slight chance" of developing.
Even when the weather is basic VFR, we can have conditions with scattered/
broken CU conditions with bases about 2000' AGL and general tops in the
10,000'-15,000' MSL area. Sometimes I can top it all and visually avoid
the LARGER buildups and thunderstorms. Sometimes I can't. If I can't,
I'll go VFR in the hot, muggy air underneath. Not pleasant. Much better
would be to stay in the relative cool air above the bases, but below the
(unreachable tops) IFR with visual dodging around the clouds. As long as
I had a device that could "look ahead" for me to see if I'm about to dodge
into something nasty.
The solution, as I see it: A storm detection system. Not to penetrate a
squall line, or a line of embedded thunderstorms, but to make a trip
through a lot of ordinary rain more relaxing.
greg
--
Gregory Reed Travis D P S I
Data Parallel Systems Incorporated gr...@dpsi.com (For MX mailers only!)
Bloomington, IN gr...@cica.indiana.edu (For the others)
Mike Myshatyn
> Gregory R. Travis writes:
> Some considerations:
> The WX-900 has only a 100 mile range. WX-1000 has a 200 mile range
StrikeFinder has a 200 nm range. You can zoom in/out to 25, 50, 100 or 200
nm. Data is always gathered for 200nm independent of what zoom window you
are presently looking at.
> The StrikeFinder can be slaved to an HSI, the WX-900 cannot.
> The WX-1000+ ($10K) can.
In addition to being able to hook up to a slaved compass system, the Strike
Finder can also be hooked up to a bootstrap synchro output from your
Heading Indicator. That way as you turn, the StrikeFinder display turns
with you. This amounts to sort of a 'poor mans' slaving. Works great - I
know.
> The WX-900 is LCD, the StrikeFinder uses a plasma display.
>
> The WX-900 is a little over 7 inches deep, the StrikeFinder over 10
> inches. Check your panel space.
This can be a problem. The benefit to the StrikeFinder is that everything
(except the antenna of course) is in one box. Makes for a cleaner
installation.
> It seems a lot of shops are much happier about BFG/Foster's support
> and test equipment it seems. Many seem to like the StormScopes
> because they are the "original."
Remember that Stormscope has been shipping for many, many years.
StrikeFinder has been shipping for less than a year. Can you say
exposure/experience? I knew you could :-)
> The StrikeFinder has an animated replay feature. No one that I
> have talked to has really used this feature. Seems like it might
> be nice though.
I do use this. It can show you how the storms are moving. This would be
very handy to know if the storms or squall line is moving towards you or
away from you.
> BFG/Foster are currently suing Insight, claiming patent infringement.
> Obviously BFG/Foster think that the Insigight technology is not
> sufficiently different from their own. Both sides
> expect victory :-)
Maybe BFG is running a bit scared that Insight might have come up with a
better technology than Stormscope?
> I went ahead with the WX-900. I couldn't justify the extra $1000.00 for
> the StrikeFinder in my little bird.
I hope your unit serves you well. I did my research on the two
alternatives and reached the opposite conclusion - I now have a
StrikeFinder in our Bonanza. Independent of which one you use/get, having
something like this is ORDERS OF MAGNITUDE better than not having the
information! Can you say peace of mind? I knew you could. :-)
> I have a problem with my (electronic) flashing beacon...
> .... If I turn off the beacon,
> the screen completely clears in about 2 minutes. The shop says this is
> a problem with the Cessna electronic beacon and they've seen it on a
> number of airplanes. They don't know of a fix except to replace it with
> a real rotating beacon. Any net.electronic wizards out there than can
> suggest a less expensive fix?
>
> I have no idea if the StrikeFinder would have the same problem.
Be advised that this is/can be a problem with EITHER Stormscope OR
StrikeFinder. And it isn't just a function of the Cessna beacon. I had a
similar problem with a Whelen strobe. Insurmountable? No. Just as yours
does, it paints in a predictable location at a predictable distance. All
that is necessary is to turn the strobe off to verify if the dots are REAL
or just the strobe. I guess it's just amazing that with all the avionics
in our planes that we don't have a real mess of an interference problem.
Some problems such as this you can live with.
--
Mike Myshatyn Bonanza N4896J Hewlett-Packard Company
ASEL/AMEL COMM, INSTR, CFI-IA User-Interface Technology Division
...!hplabs!fc.hp.com!myshatyn Ft. Collins, CO 80525
or ... mysh...@fc.hp.com (303) 229-4067
Gregory R. TRAVIS
>> Some considerations:
>> The WX-900 has only a 100 mile range. WX-1000 has a 200 mile range
>StrikeFinder has a 200 nm range. You can zoom in/out to 25, 50, 100 or 200
>nm. Data is always gathered for 200nm independent of what zoom window you
>are presently looking at.
Yet some MORE considerations. The WX-900 also gathers data at "full
resolution" regardless of the zoom window. Windows are 25, 50, 100
miles. I'm having a bit of difficulty determining if that's statute
or nautical miles.
>> The WX-900 is a little over 7 inches deep, the StrikeFinder over 10
>> inches. Check your panel space.
>This can be a problem. The benefit to the StrikeFinder is that everything
>(except the antenna of course) is in one box. Makes for a cleaner
>installation.
The WX-900 is also only two boxes - the display and the antenna. The
WX-1000(+) is three boxes - Display, Antenna, and Computer.
>> It seems a lot of shops are much happier about BFG/Foster's support
>> and test equipment it seems. Many seem to like the StormScopes
>> because they are the "original."
>Remember that Stormscope has been shipping for many, many years.
>StrikeFinder has been shipping for less than a year. Can you say
>exposure/experience? I knew you could :-)
I have to say I think you're on to something here...
For the sake of adding real data (I was going to hold off, but you've
got me started!)
Went flying yesterday with fellow netter Phil Jern. It was pretty much
light IFR all day with ceilings 2000'-3000' and visibilities between
2 and 7 in rain/fog. We were mostly able to see the ground directly downwards
but had nil forward visibility much of the time. Rain was light to
moderate. Possibility of scattered thunderstorms.
We were coming into BMG when, lo and behold, the StormSope started showing
some activity 50 miles west of BMG - about 75 miles directly ahead of us.
We turned 90 degrees and cleared the screen (we were VFR at the time).
The hits began to appear off our right side, just where they should be.
Called Flight Watch for a weather update. Nothing really serious;
"Any convective activity, say 50 miles west of BMG" "No sir, just some
level two rain."
Going from BMG to MQJ (Mount Comfort, IN) we filed because of deteriorating
conditions. The StormScope showed activity as a line of dots JUST west of
BMG as we headed northeast. At least we were going in the RIGHT direction.
Got to MQJ, got another briefing. No, no boomers anywhere. I flew back to
BMG. Had a clear screen for about 1/2 the trip. Very relaxing. But
it began to rain pretty hard and then the dots came back - just ahead of
me about 30 miles. At one point I had a CLUSTER of 4 dots, which the
manual says should always be avoided. But they were still showing about 40
miles ahead (just past my destination, BMG). At that point approach
tells a skylane that there is an area of rain right on V4 (might have
been V44) and did he want a diversion? The guys says he sees nothing
on his stormscope and he'll go through.
A few minutes later the cluster disappears. Throughout the flight back I
am getting scattered 1-2 dot "hits" that last about 2 minutes at most before
they disappear. Occasionally the screen is clear. Nothing serious (2 or
more adjacent dots) ever got within my 25 mile "danger will robinson range."
Occasionally I was in good midwestern VMC (5+ miles and 3000') and could
visually scan to try and correlate what I was seeing with the StormScope.
Never saw any weather that scared me, visually, in the least.
FlightWatch never sees anything better than level 2 rain. I was never in
anything worse than light turbulence.
A couple of times dots appeared, in the 100-mile resolution, RIGHT on top
of the symbolic airplane. I would immediately zoom in and the dot "clusters"
would show as scattered dots in 25-mile resolution. If I remember
correctly, there was usually (but not always) light turbulence at those
times.
I leared a lot about interpreting the 'scope on that flight. It seems that
dots, even ones that reappear after the screen is cleared, do not constitute
an immediate hazard. Even a tight clustering of 3-4 dots for a few minutes
doesn't seem to indicate much.
Next time I'll look for persistent "splotches" that live more than 4 minutes
and that are clearly advancing away from or towards the aircraft.
I had flown a couple of weeks beforehand towards some VERY BLACK and
VERY TALL and VERY LARGE CUs (in GOOD VFR) in the hopes of getting the
scope to show some activity. The screen was clear the whole time and I could
not see any lightning below the clouds nor observe any precip falling from
them (I never got closer than about 15 miles).
And yesterday morning, when I first flew up to mount comfort to pick up
Phil, I was in light rain the whole time and the 'scope didn't show
any "hits" for the whole trip. It didn't start showing dots until that
afternoon when they were forecasting scattered t-storms which,
according to FlightWatch/FlightService never occured.
So, perhaps it was crying wolf yesterday afternoon, but it doesn't seem
to be consistent. On a day that I was SURE I would get hits it
showed nothing. And on another, "benign," day it got quite excited.
As a pilot without the StormScope, I would have been very nervous flying
through big BLACK CUs, yet the 'scope showed nothing. In contrast,
yesterday did not "feel" like a thunderstorm day to me and if
the scope hadn't lit up I wouldn't have thought twice about the flight.
One big difference: When I was "buzzing" the CUs I was VMC the whole time -
never got wet. Yesterday, however, I was getting a good washing all day.
Sometimes the rain was rather heavy. Could precipitation static affect
the performance of the StormScope? I have no static wicks on 57E.
However, two things go against this: The lack of hits in the
morning when I was in rain and the fact that the hits in the afternoon
were consistent - i.e. I could clear the screen and turn and the hits would
reappear where you would expect them on the screen.
greg, "My God, it's full of dots..."
--
Gregory Reed Travis D P S I
Data Parallel Systems Incorporated gr...@cica.indiana.edu
Dr. Daniel R. Masys
About his Stormscope showing strikes where ATC was saying "no boomers."
Welcome to the wonderful, paranoid world of Stormscopes. I believe, based
on flying all the way across the country a couple of times during spring
and summer using a Stormscope, that returns on the scope really are
convective sparks, ATC notwithstanding. ATC is looking at precip, not
sparks to decide whether a cell is a TRW. Lightening can pop out of
rapidly rising cumulus shafts which are raining only a little, or I
believe not at all (though I am not convinced I have ever seen this
personally). It is vertical charge separation which snaps on the electricity
not precip per se.
The data point which Greg will soon get on the other side of the spectrum
is the good old fashioned mature mid-western thunderstorm. This beast
will make the Stormscope play a virtuoso light show, and is as impressive
in the display window as it is out the plexiglas windows.
Droning along in the gray muck with rain pounding on the windshield, it
is a great comfort to see a tranquil Stormscope. On the other hand, I
have had at least one experience where the first lightening strike to
be registered on the scope was a startling flash very close to the
airplane (maybe the plane precipitated it, dunno) which crackled in
my headphones, left me dazzled for a moment, and lit up half of the
scope instantly. At least there were no burn holes in the aluminum.
Don't try this at home, kids.
Dan Masys
ma...@lhc.nlm.nih.gov
Bill Standerfer
R. Masys) writes:
some notes on using a Stormscope...
>[...] ll is a TRW. Lightening can pop out of
>rapidly rising cumulus shafts which are raining only a little, or I
>believe not at all (though I am not convinced I have ever seen this
>personally).
I've seen this a couple of times, but I believe it is rare in developing
thunderstorms. I have seen many airmass thunderstorms that didn't paint any
dots on the 'scope, but later were clearly storms to be given a wide berth. I
suspect that a ride through the developing cumulus would have been "vigorous",
even without electrical activity. I get a little nervous when I'm out at night
and there is airmass convective activity, since this type of storm is usually
best avoided visually.
>The data point which Greg will soon get on the other side of the spectrum
>is the good old fashioned mature mid-western thunderstorm.
We were leaving Beatrice, NE last year with the normal 3 miles in haze stuff.
The Stormscope was showing a very lively cell about 20 miles to the south as we
taxied out. I wasn't familiar with the airport, so I didn't know if the
display was due to some underground occurrence or a real storm. We launched
and headed west for home and as we climbed above the haze, it was obvious that
the display was a real storm. Quite impressive on the display. The remaining
haze and the evening twilight made the storm a little difficult to see well.
>Droning along in the gray muck with rain pounding on the windshield, it
>is a great comfort to see a tranquil Stormscope. On the other hand, I
>have had at least one experience where the first lightening strike to
>be registered on the scope was a startling flash very close to the
>airplane [...]
I concur on the feeling you get with a quiet display. It is especially
comforting that you can see 200 miles all around if you want. That's a display
that *no* airborne radar will give you. You can check on your options both in
front of and behind the airplane.
We've had the WX-1000+ for three years now and I think it is one of the most
important instruments on the panel for serious IFR.
Bill
Bill Standerfer - KF0DJ - Baron N1746W - CFI-A, II, MEI
bi...@hpisla.lvld.hp.com
Hewlett Packard Measurement Software Division
PO Box 301, Loveland, CO 80539 -- 303-679-2378
Bill Standerfer
gr...@bronze.ucs.indiana.edu (Gregory R. TRAVIS) writes:
More Stormscope stuff...
>I had flown a couple of weeks beforehand towards some VERY BLACK and
>VERY TALL and VERY LARGE CUs (in GOOD VFR) in the hopes of getting the
>scope to show some activity. The screen was clear the whole time and I could
>not see any lightning below the clouds nor observe any precip falling from
>them (I never got closer than about 15 miles).
My personal goal of living to a ripe old age also says to stay out of the kind
of formation you described. If it looks bad visually, it probably is. In
this case, the storm may have been building and not yet really sparking. The
clue is the fact you didn't see any precip from them. Any of you severe storms
forecaster guys have any comments on this??
>One big difference: When I was "buzzing" the CUs I was VMC the whole time -
>never got wet. Yesterday, however, I was getting a good washing all day.
>Sometimes the rain was rather heavy. Could precipitation static affect
>the performance of the StormScope? I have no static wicks on 57E.
Could be. The installation material that came with ours recommends quite a few
wicks and a specific type. We still haven't put any on and don't seem to have
any problem with precip static. Maybe it is some characteristic of the
airframe that helps this or maybe we're just lucky.
Bill "dots R us"
Eric Schoen
hours, including moving a digital clock and punching a 3.125" hole in the
panel where the clock had been. (We choose to front-mount the unit, instead
of flush mounting it in a 3ATI hole, because there a panel support that would
have been in the way.) The installer tested the area where the antenna was to
be installed for excess noise (strobes, dme, transponder all running), and
found none. Much of the install time went into routing the antenna cable back
to the tailcone. A significant amount went into figuring out how to tie into
the Mooney's avionics power bus.
I flew back to Austin in 5500 MSL overcast stratus with occasional light rain
conditions. The scope showed a few isolated + signs, which the manual says
could be developing storms, or random discharges caused by atmospheric
instability. All of the isolated + signs showed up as near me, at the 100nm
range. Taxiing off the runway in Austin, I got a large dense splatter of
marks on the screen. The manual says this will happen if you taxi near an arc
welder, or over buried power lines (e.g., for the runway lights, maybe?).
Eric
--
Eric Schoen
Schlumberger Laboratory for Computer Science
Internet: sch...@slcs.slb.com In the air: N201DR
USMail: P.O. Box 200015, Austin, TX, 78720-0015