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ZL3AI > APRDIG 11.01.07 11:30l 278 Lines 10044 Bytes #999 (0) @ WW
BID : 9522-ZL3AI
Read: GUEST
Subj: [APRSSIG] Vol 31 #10, 3/4
Path: DB0FHN<DB0MRW<DK0WUE<DB0RES<TU5EX<IW2OAZ<ZL2BAU
Sent: 070111/1028Z @:ZL2BAU.#79.NZL.OC #:26313 [Waimate] $:9522-ZL3AI
From: ZL3AI@ZL2BAU.#79.NZL.OC
To : APRDIG@WW
Message: 20
Date: Mon, 8 Jan 2007 22:14:35 -0800
From: "Cap Pennell" <cap_at_cruzio.com>
Subject: RE: [aprssig] APRS for a "ocean buoy"
Most parts of coastal California are populated with nearby mountaintop
digipeaters. VHF could work fine much of the time (because of the digis
atop those mountains). But if "conventional satellite tracking (Argos,
Orbcomm, Inmarsat D+)" alternatives are available, then APRS (VHF or HF) may
not be the most appropriate mode.
73, Cap KE6AFE
Perhaps the California APRS Users group could provide more local info.
http://groups.yahoo.com/group/ca_aprs/
News, discussion, and questions about APRS in California (and nearby
portions of adjacent states) will continue there.
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Message: 21
Date: Mon, 8 Jan 2007 22:31:46 -0800
From: Ben Jackson <ben_at_ben.com>
Subject: Re: [aprssig] APRS for a "ocean buoy"
On Mon, Jan 08, 2007 at 08:39:06PM -0800, Jim Lux wrote:
>An acquaintance asked if there was decent APRS coverage along the
>coast of California, say out to 10-20 mi from the shoreline. The
>transmitter would be pretty close to sea level (on a kayak, for
>instance). 30m HF is an option, but there was some uncertainty about
>what sort of antenna would be possible for that.
I was interested in the same thing. I'd still like to build a buoy, but my
findings suggested I needed a new design and a dedicated listening station.
VHF is line of sight. 10-20mi out is not really practical for a buoy which
is practically "on the ground". 30m HF has its own problems. There aren't
many listening stations. I built a 5w transmitter and ran it from my home
in Beaverton, OR (near Portland). I was able to hit two HF listeners, one
I think is in south central Washington and one in the LA area. That
required a second story dipole. Packets only got through during band
openings a few times a day.
The main things I need to change are:
1) More powerful transmitter. 5w was marginal on a much better antenna
than a buoy would have. I've done tons of antenna simulations looking at
various configurations, and even with fairly tall (3+ meters)
configurations and assuming saltwater was a fabulous ground, the buoy
antenna is pretty lossy. 15w seems reasonable for a buoy, given the low
duty cycle. My notes show that 32lb of D batteries cost ~$100 and have
around 2500wh which is about 3000 powerup/transmit cycles assuming a 15w
final.
2) A more stable transmitter. 20ppm doesn't cut it for HF packet. 1ppm
is 10Hz at 30m, sub-ppm would be better. The minimum standard would be a
TXCO. Better would be a TXCO with long-term compensation using the GPS
timebase.
3) A dedicated listening station. It's very hard to locate HF stations,
but I'm fairly sure there are only about 3 on the west coast. Even if I'm
off by a lot, it's still far, far less than the number of VHF listeners.
And if they have any directional gain, it's probably not out to sea. If I
had a buoy out there, I'd want to set up a big beam or maybe a rhombic
pointing at the Pacific. I have a friend with a farm closer to the coast,
so I could put something up there.
--
Ben Jackson AD7GD
http://www.ben.com/
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Message: 22
Date: Tue, 09 Jan 2007 07:34:25 +0100
From: "Jan T. Pharo" <la2bba_at_jpharo.net>
Subject: Re: Eagle Scout Icon - Was Re: [aprssig] APRS data for Scout
Events
"Rod,VE1BSK" <rodpadmore_at_ns.sympatico.ca>, Mon, 8 Jan 2007 21:49:12
-0400:
>BTW, doesn't the fleur-de-lis represent the whole Scout movement
>world-wide and wouldn't this be a neat icon?
No, it doesn't. The international girl scout and girl guide asscn. is
using a trifoil. Hence my symbols for my own use (available at my
ui-webserver site <http://la2bba.jpharo.net>, but some other symbols
there are probably changed since I made that setup)
--
73 de Jan, LA2BBA
Hvaler, Norway
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Message: 23
Date: Tue, 9 Jan 2007 09:16:34 -0000
From: "Dave Baxter" <dave_at_emv.co.uk>
Subject: Re: [aprssig] dos on a winxp machine
You may have to "Fight" the system to get access to any ports, serial or
parallel in CMD mode, the information how to do that, is on MS's
KnowledgeBase site, but finding it is a pain. (Network access though,
not a problem!)
Even when/if you can, you will find all the timings a bit screwey...
Win2k and XP's "Command Mode" is not like DOS at all, it just looks like
it.
Interestingly, the original install of 2000 would allow you full access
to the com and lpt ports, but post SP4, that was blocked by default.
That caused our company a "Huge" problem, and I spent hours rewriting
many simple software device configuration tools to run "within" Windows.
Time well spent in the end, but...
AFIK XP never allowed it by default in any release.
Anyone else know more ??? Odd registry or machine hacks and the like
???
73
Dave G0WBX.
------------------------------
Message: 24
Date: Tue, 9 Jan 2007 18:51:41 +0800 (CST)
From: M J <mjandthegang_at_yahoo.com>
Subject: Re: [aprssig] APRS for a "ocean buoy"
Jim,
I may be assuming incorrectly on this, but I am wondering if your project
includes sending data about oceanographic conditions or if the need is
simply that of geolocating the buoy?
If this is about sending oceanographic conditions, I am wondering about the
equipment used to monitor and how it is embedding the data in the
transmission. I found the APRS protocol online but I don't see anything in
the protocol that would allow for much beyond sending basic weather
information.
I can imagine that APRS ought to be able to convey a lot of data such as
solar radiation, river flow, water height, atmospheric opacity but I'm
having trouble finding a way that such information can be embedded and
parsed in a standard way.
If this is considered off topic I would be appreciative of a direct reply.
By the way, a couple of my EE college friends are now monitoring the list.
This is quite interesting. Thank you!
MJ
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Message: 25
Date: Tue, 9 Jan 2007 21:06:56 +1000
From: "Andrew Rich" <vk4tec_at_tech-software.net>
Subject: [aprssig] Quad antenna construction techniques
Gudday
Building a quad for vhf for aprs.
I have tried metal boom (hopeless) plastic (ok) and wood (good)
I am open to suggestions on how to hold the vhf quad elements in place.
I have used dowel spreaders with notches cut into them before.
How about arrows ? they seem to have plastic bit at the end - a "bow nock"
I would like to try some more rigid wire this time, last time i used some
failry flimsy stuff.
Got any tips for building 145 MHz quads ?
Cheers
Andrew Rich
Amateur radio callsign VK4TEC
email: vk4tec_at_tech-software.net
web: http://www.tech-software.net
Brisbane AUSTRALIA
------------------------------
Message: 26
Date: Tue, 9 Jan 2007 04:28:04 -0800 (PST)
From: Shanon Herron <ka8spw_at_sbcglobal.net>
Subject: Re: [aprssig] Quad antenna construction techniques
I Rich,
I usually slide a snug fitting hardwood dowel rod into the PVC to stiffen
it up.
Good luck, Shanon KA8SPW
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Message: 27
Date: Tue, 9 Jan 2007 07:49:22 -0500
From: "Richard Amirault" <ramirault_at_verizon.net>
Subject: Re: [aprssig] Quad antenna construction techniques
----- Original Message -----
From: "Andrew Rich"
Subject: [aprssig] Quad antenna construction techniques
>Building a quad for vhf for aprs.
>I have tried metal boom (hopeless) plastic (ok) and wood (good)
>I am open to suggestions on how to hold the vhf quad elements in place.
>I have used dowel spreaders with notches cut into them before.
>How about arrows ? they seem to have plastic bit at the end - a "bow nock"
(snip)
Many (most?) arrows are carbon based and will conduct electricity. Not sure
how well they would be for spreaders. Wooden dowels or fiberglas rods will
work. You can purchase JUST the arrow nock to attach to the ends.
Richard Amirault N1JDU
Boston, MA, USA Go Fly A Kite
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Message: 28
Date: Tue, 9 Jan 2007 06:30:28 -0800 (PST)
From: "Curt, WE7U" <archer_at_eskimo.com>
Subject: Re: [aprssig] Quad antenna construction techniques
On Tue, 9 Jan 2007, Richard Amirault wrote:
>Many (most?) arrows are carbon based and will conduct electricity. Not sure
>how well they would be for spreaders.
>Wooden dowels or fiberglas rods will work. You can purchase JUST the arrow
>nock to attach to the ends.
Hmmm. You never know where discussions will lead on this sig!
I'm a bowhunter so I have a few arrows of different types that I've
collected over the years. Cedar shafts are common for the recurve or
longbow enthusiasts (which I'm not). Once you get into the
"training-wheel" bows you switch to aluminum or carbon as the wooden shafts
will shatter on you. I shot aluminum shafts for many years but shoot
carbon with my latest bow.
You can buy shafts w/o fletching with a nock already mounted on one end.
Depending on the type of shaft you may easily be able to put a nock on the
other end, or it may require the expertise of an archery shop to machine
the end and/or glue the nock on properly. Some nocks glue inside the
shaft, some glue onto the outside.
If you were nearby I'd hand you some cedar or aluminum shafts that I most
likely won't be using again.
For 2-meter quads you'll need spreaders longer than you can find in an
arrow shaft, so perhaps wooden or fiberglass rods with arrow nocks glued on
might work for you. That's if you can get the right diameter nocks to fit
the rods. Definitely an interesting way to do it!
Check out Cabellas online store to see what nocks and shafts are available,
or one of your local archery stores.
--
Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer
"Lotto: A tax on people who are bad at math." -- unknown
"Windows: Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me: I picked the coordinate system!"
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