On Wed, 01 Dec 2004 17:58:21 -0500, Ryk
wrote:

On Wed, 01 Dec 2004 19:03:59 GMT, "Glen \"Wiley\" Wilson"
wrote:

It's doable, but the data filtering will be tricky. I've found that
you can't always trust the gps to notice that it's lost accuracy, so
I'll have to implement some kind of statistical filter that ignores
the big jumps but notices a small steady drift.

My recent GPS experience differs from yours, tracking pretty steadily
without glitchy jumps.

Perhaps you have a superior antenna setup to the customer who
requested the function. There are a lot of people out there feeding
their laptop with an old Garmin 48 mounted in the cabin.

I haven't quite worked out how to handle wind and current reversals
yet. If you could do that, you could tighten the safe distance quite
a bit. It seems that treating the safe swing area as a circle around
your current position, as anchor alarms do, is wrong. It's really a
circle around the anchor's position. Maybe a bearing and distance to
the anchor float could be used as an offset to current position?

I have some very convincing GPS tracks watching my boat swing around
its anchor, showing the circle around the anchor. I like having the
alarm wake me in the night even if it's just a swing through a
significant chunk of arc. I also like having the GPS maintaining it's
display track right by my berth. It's very reassuring to look over and
see my position smack in the middle of hours of accumulated data.

Yes, that's the way Ozi works as well, and pretty much what I would
do, as a default.

But you raise a good point. The function should be highly
configurable as to what the user considers to be a valid wakeup call.

That's really the hard part. As a start, allow the user to select
"Alarm on drag" and/or "Alarm on swing", then implement the two
algorithms, and add all the needed options.

It gets complex, especially given that there's probably not much of a
market for the feature. I could knock out a simple "me too" alarm
tonight, but where's the fun in that? It might be a better candidate
for freeware than shareware though



__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

On Wed, 01 Dec 2004 19:03:59 GMT, "Glen \"Wiley\" Wilson"
wrote:

Actually, I think that's an excellent idea, but I rolled my own. See
the crass commercial message in my sig. :-) I've been asked to
extend the program with an intelligent anchor watch. Something
that would suppress spurious alarms when the gps loses lock for
a few seconds. I'd never have thought of that myself, but it's a
fact that I've never had a complete night without my gps deciding
Scotty beamed me a few hundred yards in some random direction.
Which causes OziExplorer's otherwise excellent anchor watch to
start screaming.

If your GPS produces a spurious jump when it loses lock, I think a new
GPS is in order. I have been using GPS receivers for 15 years, and
have never had anything like that happen.

I have seen them keep the last readout, blinking the display. The
blinking wouldn't show up on the NMEA, I suppose, but the unchanging
readout would fail as an anchor alarm if you actually were adrift.

What kind of reciever did what you describe?

Another thing. Where are you anchoring that it loses lock nowadays,
with 24 sats active? When I had a 6-channel receiver it would lose
lock all the time in a Manhattan bus, but never on the boat.

At that time "Selective Availability" would have made it useless as an
anchor alarm, but that is a separate issue, still long behind us. WIth
luck it will stay that way.

Rodney Myrvaagnes J36 Gjo/a

The destruction of the World Trade Center was
a faith-based initiative. -- George Carlin

Sorry, didn't work. Everything is still the same.

"rhys" wrote in message
...
On Tue, 30 Nov 2004 18:46:50 -0500, "Doug Dotson"
wrote:

How did the "captain's compass" get into the "Air-X marine wind generator"
thread?
Kind of annoying.

Doug
s/v Callista

Doug, your newsreader or news serverr has scrambled your message list.
This thread is properly called "Captain's Compass".

I suggest to fix it you delete this group as subscribed, then
RE-subscribe, which will bring you several months' worth of messages.
Delete from the beginning to, say, the last month (Oct 30). This will
preserve all threads currently in play (likely that you are following)
and the NEXT time you download news group messages, you should see
that all messages are where they should be.

R.

On Wed, 1 Dec 2004 23:52:21 -0500, "Doug Dotson"
wrote:

Sorry, didn't work. Everything is still the same.

I don't know then. In my newsreader, this thread is still called
"Captain's Compass".

Cross-posting problem, mebbe?

R.

So is mine, but this "compass" thread started as a reply to one of
your posts to the "generator" thread, rather than a top level post.

Doug

"rhys" wrote in message
...


On Wed, 1 Dec 2004 23:52:21 -0500, "Doug Dotson"
wrote:

Sorry, didn't work. Everything is still the same.

I don't know then. In my newsreader, this thread is still called
"Captain's Compass".

Cross-posting problem, mebbe?

R.

Hi James

I have just done a delivery from Frazer Island to Hobart in Australia, about
1,300 nm, on a 45 footer with an Air-X generator.

I found that it did not cut in until about 15 knots apparent wind when it
generated about 5 amps. This increased to 10 amps at 20 knots and 15 amps
above 25 knots.
The noise was quieter than other wind generators that I have used, much
quieter than my old Airogen, but as the voyage progressed the noise became
more annoying. It was particularly intrusive when the winds were over 30
knots apparent.

Also, as the vessel rolled and pitched, the Air-X changed direction slightly
and the rotation accelerated and decelerated, which changed the tone of
noise it made. One crew member said it reminded him of the soundtrack of
diver bombers in a war film!

Hope this helps

Graeme
sv Leonidas

James wrote:

I am looking at wind generators. According to the latest literature, the
Air-X marine wind generator is claimed to be 80% less noisy than the
(very loud and annoying in my opinion) older model, the Air Marine.

Can anyone offer any first hand experience with Air-X Marine wind
generator as compared to the old Air Marine one?

Also, does anyone have any recommendations for products in particular?
Real world experience is what I am looking for...the advertisign hype
isn't much use. Experience is.

Thanks

Jimmy