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ZL3AI > APRDIG 09.12.03 10:44l 279 Lines 9721 Bytes #999 (0) @ WW
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To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Thursday, December 04, 2003.
1. Garmin Rhino 110 &120
2. APRS HF Antenna dimensions
3. Re: APRS HF Antenna dimensions
4. Re: WX Station decode... Kenwoods
5. RE: APRS HF Antenna dimensions
6. RE: APRS HF Antenna dimensions
7. Re: APRS HF Antenna dimensions
8. NMEA at >100,000 feet
9. Re: NMEA at >100,000 feet
10. Requested APRS data sentence from Peet Units
11. Peet WX Station decode for APRS
12. APRS WX Protocol Questions
13. I-Gate Without a Computer
14. Re: NMEA at >100,000 feet
15. Re: APRS WX Protocol Questions
16. Re: APRS WX Protocol Questions
17. Re: APRS WX Protocol Questions
18. National Parks Digi Coverage (Rev 3)
19. Re: NMEA at >100,000 feet
20. Re: APRS WX Protocol Questions
21. Re: National Parks Digi Coverage (Rev 3)
22. Re: NMEA at >100,000 feet
23. Re: National Parks Digi Coverage (Rev 3)
24. Re: NMEA at >100,000 feet
25. NMEA at >100,000 feet
26. Re: NMEA at >100,000 feet
27. Re: NMEA at >100,000 feet
28. Re: NMEA at >100,000 feet
29. D700 Problem
30. Re: D700 Problem
31. Re: National Parks Digi Coverage (Rev 3)
32. RE: D700 Problem
33. Re: National Parks Digi Coverage (Rev 3)
34. Re: APRS WX Protocol Questions
35. Re: APRS WX Protocol Questions
36. Re: National Parks Digi Coverage (Rev 3)
37. Re: APRS WX Protocol Questions
38. RE: I-Gate Without a Computer
39. Re: National Parks Digi Coverage (Rev 3)
40. Re: National Parks Digi Coverage (Rev 3)
41. Re: National Parks Digi Coverage (Rev 3)
42. RE: APRS HF Antenna dimensions
43. Re: APRS WX Protocol Questions
44. RE: D700 Problem
45. Re: National Parks Digi Coverage (Rev 3)
46. Re: APRS WX Protocol Questions
47. Re: National Parks Digi Coverage (Rev 3)
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Subject: Garmin Rhino 110 &120
From: Reid Crowe <bigreidous@sbcglobal.net>
Date: Wed, 3 Dec 2003 21:17:47 -0800 (PST)
X-Message-Number: 1
Has anyone figured out if it is possible to change the frequency on these
radios to go down to the Ham band?
73 Reid KC=D8IDI
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Subject: APRS HF Antenna dimensions
From: "Andrew Rich" <vk4tec@hotmail.com>
Date: Fri, 5 Dec 2003 21:54:02 +1000
X-Message-Number: 2
Can someone tell me what is the length of a dipole at 10.149.0 MHz. I get
conflicting reports.
Cheers Andrew vk4tec
PS suggested length is 46.11 feet across
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Subject: Re: APRS HF Antenna dimensions
From: "Joel Black" <w4jbb@charter.net>
Date: Thu, 4 Dec 2003 06:15:21 -0600
X-Message-Number: 3
468 / 10.149MHz = 46.11 for 1/2-wave dipole.
GL es 73,
Joel B. Black
w4jbb@charter.net
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Subject: Re: WX Station decode... Kenwoods
From: Henk de Groot <henk.de.groot@hetnet.nl>
Date: Thu, 04 Dec 2003 15:10:13 +0100
X-Message-Number: 4
At 09:28 3-12-2003 -0500, Bob Bruninga wrote:
>On Tue, 2 Dec 2003, Byron Smith wrote:
>>This was a very myopic choice on their part. I wonder who told them
>>this was OK?
>
>Yep, it was me. At the time, there were 5 different formats from Peet
>Bros alone, and they were changing every year. (1997) At that time, most
>everyone with a WX station was running a PC with it and so it was
>extremely rare for there to be any stand-alone WX stations. Since the
>Kenwood had to nail down the ROM code then, and the Peet bros formats were
>still changing, the only safe option was to go with the APRS format only.
I think it was the only sensible choice, even if it was done today. If
there ever was a myopic choice, then it was the inclusion of vendor
specific formats in the APRS SPEC. Why specify many different formats to
convey exactly the same information... That also applies to at least 5
flavours of position reporting; regular, compressed, MIC-E and at least 2
raw GPS strings.
Note that pocketAPRS also does not decode WX packets at all to date. One of
the reasons is lack of space to handle all these different formatats;
exactly the same reason why Kenwood could not include all of them. Mike
still wants to add it, but just like the Kenwoods only the APRS type.
Maybe its about time that somebody writes a converter to convert all these
WX reports to a unified APRS message. But I guess we have to wait for
Opentrac to solve this once and for all too.
Kind regards,
Henk.
P.S. I still find it a pity that the APRS format uses Imperial measures
instead of ISO/metric, that makes it hard for me to read the rain-counter
im mm :-(. But I guess at your side of the ocean you are happy with the
1/100 inch value for the rain-counter...
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Subject: RE: APRS HF Antenna dimensions
From: "Scott Miller" <scott@3xf.com>
Date: Thu, 4 Dec 2003 07:20:57 -0800
X-Message-Number: 5
Ahem.
USE 4-6-8 OVER 'F' TO CALCULATE! DIPOLES! DIPLOES! RA!!!!
(Damn you WB6BYU, Novice class was 15 years ago and I still can't forget
that formula.)
Scott
N1VG
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Subject: RE: APRS HF Antenna dimensions
From: Bill Vodall - WA7NWP <wa7nwp@jnos.org>
Date: Thu, 4 Dec 2003 08:11:01 -0800 (PST)
X-Message-Number: 6
Here's a trick question.
Excluding velocity factor, what's the lenght of a half wavelength dipole
for the '30 meter' band?
Took me years to grok the relationship and things came much clearer when I
finally did.
Of course velocity factor, wire size, height above ground and surrounding
objects change everything and there's no absolute equation. Antennas need
to be tweaked.
Bill
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Subject: Re: APRS HF Antenna dimensions
From: w2kb@comcast.net
Date: Thu, 04 Dec 2003 16:21:46 +0000
X-Message-Number: 7
formula for length of a half-wave dipole in feet is 468 / frequency in MHz
which would yield the 46.11 feet. But that's a starting point and local
environmental factors will cause it to vary. An easy way to do it is to
make it slightly shorter, say 45 feet, and then solder on 12 inch drooping
pigtails to each end. Trim them equally in small increments to get SWR to
the lowest point.
73,
---Ken
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Subject: NMEA at >100,000 feet
From: "Scott Miller" <scott@opentrac.org>
Date: Thu, 4 Dec 2003 10:45:57 -0800
X-Message-Number: 8
Does anyone have a sample of actual NMEA output from a GPS at an altitude
of greater than 100,000 feet? Gotta get the altitude parser working for
the OpenTracker tonight. I can fake a file with what I think it should
look like, but I'd rather see the real thing just to be sure. Not that I
would expect it to look any different save for an extra digit, but I'd
rather find out now.
Has anyone had any experiences with reed relays at low temperatures? I'm
thinking of using one to trigger a camera's shutter, and it's rated to -20
C, but the required activation voltage rises as it gets colder and I'm
worried about it not being triggered by a TTL output. Also, I was looking
at the specs for the 78L05 voltage regulator, and the TO-92 package is only
rated to 0 C. With the amount of power it's dissipating I can't imagine it
getting too cold, but I'm new to this sort of thing. I think I might pick
another, lower drop-out regulator anyway.
Thanks.
Scott
N1VG
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Subject: Re: NMEA at >100,000 feet
From: Bob Bruninga <bruninga@usna.edu>
Date: Thu, 4 Dec 2003 14:04:09 -0500 (EST)
X-Message-Number: 9
On Thu, 4 Dec 2003, Scott Miller wrote:
>Has anyone had any experiences with reed relays at low temperatures? I'm
>thinking of using one to trigger a camera's shutter, and it's rated to -20
>C, but the required activation voltage rises as it gets colder and I'm
>worried about it not being triggered by a TTL output. Also, I was looking
>at the specs for the 78L05 voltage regulator, and the TO-92 package is only
>rated to 0 C. With the amount of power it's dissipating I can't imagine it
>getting too cold, but I'm new to this sort of thing. I think I might pick
>another, lower drop-out regulator anyway.
Remember, the sun is shining up there above the clouds and things only get
cold if you put them in White Styrofoam to try to "insulate them". Then
they get as cold as the air temp (which is very cold, but also ver thin).
But if they are black and in the sun, then they stay warm.
But then they are harder to see and dont have the safety of FOAM when it
lands on someone. We solved the problem by placing our 8 AA cells in a
clear plastic coke bottle and painted the cells black and the sun kept
them warm. In fact, the temperature only went up not down as it got above
the clouds...
So things dont have to be cold unless you design it that way..
Bob
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Subject: Requested APRS data sentence from Peet Units
From: Ralph Milnes <ralphmilnes@patmedia.net>
Date: Thu, 04 Dec 2003 14:07:20 -0500
X-Message-Number: 10
I'm sending a second message to the reflector which is a courtesy copy of
my reply to Peet Bros., who had responded to my request for a new APRS
sentence with a "it would be too hard to do" .
I may not be going about this the right way with them, but let's see what
happens.
To give them a sense of what I wanted, I paraphrased parts of the APRS Spec
-- I hope correctly, but maybe not.
Comments welcome.
Ralph KC2RLM
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