| |
ZL3AI > APRDIG 20.02.04 14:48l 252 Lines 9529 Bytes #999 (0) @ WW
BID : 2878-ZL3AI
Read: GUEST
Subj: TAPR Digest, Feb 18, 5/6
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<7M3TJZ<WB0TAX<N1UAN<ZL2TZE<
ZL3VML
Sent: 040220/1236Z @:ZL3VML.#80.NZL.OC #:19473 [Chch-NZ] FBB7.00i $:2878-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: "Its just a hobby" (not!)
From: "Spider" <spider@rivcom.net>
Date: Wed, 18 Feb 2004 16:58:25 -0700
X-Message-Number: 30
----- Original Message -----
From: "Jeff King" <jeff@aerodata.net>
>> This is after all a hobby.
>
>No, it is a way of life. You either do things right in your life, or you
>don't. This is exactly why most APRS applications, be it the GUI's or
>internet mapping applications, rival commercial products. These are serious
>people doing this. And of the authors I know in APRS, almost to a one, they
>also are well respected at their place of work or school.
>
>It is a passion.
Right on Jeff! Except, I've started talking to myself again! "I am not an
idiot, I am not an idiot!"
Jim, WA6OFt
----------------------------------------------------------------------
Subject: Re: Amperage rating of cigarette ligher plug
From: "Germino" <mgermino@sbcglobal.net>
Date: Wed, 18 Feb 2004 16:11:28 -0800
X-Message-Number: 31
When I worry about the draw from the lighter plug I put a gell cell inline
and that gives more than enough capacity. Maybe with the short TX times of
APRS one of those large capacitors that the large audio amp crowd use might
work. Then you don't have to worry about over charging the gell cell.
Mike
73, AD6AA
----------------------------------------------------------------------
Subject: Alternate Balloon Paths
From: "Paul Wightman" <pwightm@CLEMSON.EDU>
Date: Wed, 18 Feb 2004 19:23:29 -0500
X-Message-Number: 32
Hello, all.
I am a student at Clemson University and am involved in a new project aimed
at building and launching a balloon to conduct a few experiments as well as
take pictures every so often. We will be using APRS to track our balloon.
Needless to say, I was excited to see this being discussed on the SIG.
I have been considering various configurations that would allow us to
reliably track the balloon and, at the same time, limit large-scale
interference with the APRS network. One option that I have considered is
coordinating with digipeater operators in upstate South Carolina, northeast
Georgia, and southwest North Carolina so that we could use a generic path of
"BALLOON", for instance, instead of WIDE. This, I believe, would
considerably reduce congestion while the balloon is at high altitudes.
Furthermore, since digipeaters outside our target area would "ignore" our
packets, we would be able to use slightly (only slightly!) higher power,
which very well may make a difference should the balloon land in an outlying
area surrounded by ridges - a very real possibility in the upstate.
Granted, this approach would take a considerable amount of planning and
effort - from both the ballooners and the digipeater owners - in comparison
to simply using WIDE and, quite possibly, may not be feasible in some areas
depending on technology, etc. I certainly would not expect digipeater
operators to make a special trip up to their repective sites in order to
change one parameter. Instead, I would hope that remote control could be
used. Given plenty of planning, though, it may be possible for them to add
the change to their list of "to-do's" for their next trip.
This approach may not be worth the extra time and energy, especially for
one-time flights. However, we hope to make balloon launches a semi-regular
event (at least one every year or two) at Clemson, so a little prior
planning may prove useful as the APRS network continues to grow.
Just thought I'd throw this idea out. I'd be happy to hear any
comments/suggestions either on or off the SIG.
Thanks & 73,
Paul Wightman, KF4UIA
pwightm@clemson.edu
----------------------------------------------------------------------
Subject: Re: Excessive paths on balloons was RE: High Altitude Balloon Flights
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Wed, 18 Feb 2004 19:33:15 -0500
X-Message-Number: 33
>>>"Scott Miller" <scott@opentrac.org> 2/18/04 5:49:38 PM >>>
>It seems to me that it'd still be useful for recovery though. Since the
>OpenTracker now has the capability to drop the path above a specified
>altitude, what would you suggest for a standard setting? I think it
>defaults to 4999 meters right now.
I like the idea someone posted of just no movement. (but data still
valid and in lock). No movement for more than 30 seconds?
This will work in Denver and Florida.
WIDE while moving
RELAY,WIDE when stopped.
I dont think any further hops are needed since if the GPS was working when
it got near the ground, everyone knows what digi its near and will drive
there.
I toyed with the idea of NO DIGI while moving, but that is dangerous,
because I can imagine the last 200 feet skimming along in a valley and not
anyone hearing it direct..
de WB4APR, Bob
----------------------------------------------------------------------
Subject: Tetroon construction?
From: Jeff King <jeff@aerodata.net>
Date: Wed, 18 Feb 2004 20:12:03 -0500
X-Message-Number: 34
I'm trying to figure out how to build one of these, and this is what I have
found so far:
http://tetroon.hypermart.net/
http://tetroon.hypermart.net/TOM.html
http://www.deering.org/balloon/tetroon.xls
And from these I can see the tetroon is 4 equilateral triangles.
Now, these can be placed together to form a parallelogram.
And then by dividing the parallelogram back into 4 equilateral triangles, it
can be folded to make a tetroon, and only three sides need to be joined. The
rest are continuous material.
Looking at the hardware store, I see something call "painter's plastic" which
comes in 12' x 400' rolls:
http://paint-and-supplies.aubuchonhardware.com/tape_and_drop_cloths/drop_cloth
s/high-density_painter's_plastic-788669.asp
So, one $19 roll would make ~11 11.2' high tetroon's.
Anyone have any thoughts on a lightweight tape that could be used to join
this thin plastic and any other thoughts?
--
Jeff King, jeff@aerodata.net on 02/18/2004
----------------------------------------------------------------------
Subject: RE: Tetroon construction?
From: "Rochte, Robert" <rrochte@gpacademy.org>
Date: Wed, 18 Feb 2004 20:21:37 -0500
X-Message-Number: 35
Sure. First, you can heat seal it. That's the best idea. Second, you can
use tape - common Scotch tape works fine or you can opt for something more
expensive. You can even get really fancy and use Sheldahl thermal adhesive
tape if you want.
My tetroons are heat sealed, but I used plain old Scotch tape (ala Jean
Piccard in the 1930s) to patch the SD4 tetroon.
Tom Deering's site is good (based on Don Piccard's XAP project), but check
the numbers in his spreadsheet before you bet your life on it. And Tom
doesn't much like hearing that his calculations are wrong...
-R
>Anyone have any thoughts on a lightweight tape that could be used to join
>this thin plastic and any other thoughts?
----------------------------------------------------------------------
Subject: RE: Excessive paths on balloons
From: "Rochte, Robert" <rrochte@gpacademy.org>
Date: Wed, 18 Feb 2004 20:28:08 -0500
X-Message-Number: 36
>But here is the consequence of RELAY at the start of
>RELAY,WIDE,WIDE. It can tie up more than 50% of
>the channel over thousands of square miles for 10,20
>30 seconds at each packet!
>
>1) Lets sayt 100 digis hear the packet
>2) Assume that each digi hears 3 others.
>3) Assume that each digi hears 10 stations (RELAYs)
>4) EVERY RELAY (and every digi) digipeats the paceket.
[Edited to please the Lyris God...]
I've all responses and certainly understand and agree with all points made.
But I'm wondering - since we often do this sort of theoretical projection
here - how does this check out with the reality of the SD4 tetroon flight?
Since we have a real-life example so close at hand, is there any way to
actually *measure* the congestion that was created and compare it to this
model?
73,
Robert
----------------------------------------------------------------------
Subject: Re: Amperage rating of cigarette ligher plug
From: James Jefferson <jj@aprsworld.net>
Date: Wed, 18 Feb 2004 21:06:13 -0600
X-Message-Number: 37
Consider running some 6 guage wire directly from your battery back to the
radio. You can run it underneath the vehicle fairly easily. Or remove the
plastic trim between the edge of the door and the carpeting and drop it in
the slot with all of the other wire. This is how I've done it on three
vehicles in the past.
THHN wire is oil and gas resistant and should be available quite cheaply,
otherwise welding wire is more flexible and has an even more resistant
jacket.
A fine source of automotive wiring supplies (at least for the US, I don't
know about their Canadian shipping policies) is Waytek Wire. They are at
www.waytekwire.com. Not affiliated, I've just been quite pleased with them.
-Jim
----------------------------------------------------------------------
Subject: Re: Amperage rating of cigarette ligher plug
From: David VanHorn <dvanhorn@cedar.net>
Date: Wed, 18 Feb 2004 23:00:59 -0500
X-Message-Number: 38
>Other thought, if the transmission is brief, then you can probably do an
>LC filter at the radio end with a large capacitance to handle the brief
>transmission. You would have to calculate how much energy you will draw and
>the allowed voltage drop on the power line to determine the minimum
>capacitor value.
>Derek
>KE6JTP
This would take an enormous capacitor, to be of any use.
----------------------------------------------------------------------
Read previous mail | Read next mail
| |
