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ZL3AI > APRDIG 26.07.03 09:14l 222 Lines 9422 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Jul 23, 7/8
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: PHGr just got better! It's PHGra
From: "Ev Tupis (W2EV)" <w2ev@arrl.net>
Date: Wed, 23 Jul 2003 19:55:35 -0400
X-Message-Number: 41
Taking Bob's PHGr construct to the next level was easy. Because it is a
variable length field (always starts with "PHG" [CAPS only] and ends with
"/") this was a no-brainer. What was added? I'm glad you asked! :)
Altitude Above Mean Sea Level. This is a very important component to
propagation research...especially on HF frequencies. The scale and values
are identical to what is presently used for the "H"AAT component that is
already in PHG. This is referred to as PHGra and is now being adopted by
the PropNET community.
Thanks to Andy, there's even an on-line calculator that includes it:
http://www.apritch.myby.co.uk/phgracalc.htm
fwiw...
Ev Tupis, W2EV
http://www.PropNET.org
PS...yes, I know there are still drawbacks to PHG (like inability to note
negative HAAT and the limited scale or resolution of some of the values), but
this is still a significant leap forward. Give it a try!
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Subject: RE: Reality check needed re uptimes and a soapbox rant, like it or not.
From: "Dave Anderson" <dandersn@citicom.com>
Date: Wed, 23 Jul 2003 19:59:43 -0400
X-Message-Number: 42
>This is why I made the comment on the other thread that I
>believe that
>many/most/some/whatever number of clients and sysops are praising the
>effort to have ports that do not spew the full APRS feed.
Filtered feeds -have- to be in existance. The lion share of users on
aprsfl.net either use the filter, or use a port with a regional feed. Yes,
I know Phil, that's the Tier 2 philosophy. I certainly wouldn't run these
configurations if they weren't well planned and needed in my opinion :)
>Can you imagine
>what would happen if we took the 200+ or so users off the
>Tier 2 network
>now at this point in the game and put them on port 23/10152 full-feed
>connections? Scary thought in my book. Thanks for listening.
I did the math, right now, based on user connects to all of the connections
between the tier2 sites and the core sites that offer filtering - and looked
at sheere packet quantity. The numbers -are- scary.
As noted before --- you may be able to push a full feed of -data-by-itself-
bandwidth wise down a 28.8k PPP session, but generally the packet -overhead-
of said amount of traffic in the current design of APRS-IS will well exceed
the 28.8 session.
Seeya,
Dave
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Subject: PSR deadline
From: Stan Horzepa <stanzepa@earthlink.net>
Date: Wed, 23 Jul 2003 20:00:06 -0400
X-Message-Number: 43
The deadline for TAPR's quarterly newsletter, Packet Status Register (PSR),
is upon us. Please e-mail your input for PSR to wa1lou@tapr.org as soon as
possible.
Thank-you,
Stan, WA1LOU
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Subject: Re Stations Heard:Portable in Bimini/C6A
From: WB4GQK@aol.com
Date: Wed, 23 Jul 2003 20:35:07 EDT
X-Message-Number: 44
I was indeed very interested in station reception that Rich had experienced
on his fishing trip to Bimini, so I checked my log for the evening of
7/20/03 covering the same 4 hours and 36 minutes that I recorded 20 of his
transmissions.
My log shows that I recorded 48 stations over that identical period of time
with many repeats such as VP5DB-2 with 31 repeats, VP5DB-1 with 12, VP5DB
with 4, PJ5DM-1 with 9, C6AGH with 8, K1PIG with 4 (from Maine yet), W1ON-3
with 3 (another NE station). These were the 4 stations listed.
What I find somewhat unusual is the two stations that have very strong
signals easily 20 over here in St Petersburg are K5RAV with 8 repeats(from
South TX), and N5NGN with 3 (from GA) was not copied in Bimini. I would
venture to say it was a fairly busy evening.
This little disclosure is in no way meant to belittle what was accomplished
in a temporary setup, because the transmissions were copied by my station.
So the HF signal was getting out. What I do feel is very important for all
other APRS readers is to realize that 30 M APRS has a lot of activity which
was not apparent in the referenced message.
Jim WB4GQK
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Subject: Re: running a laptop in the car
From: "Mike Yetsko" <myetsko@insydesw.com>
Date: Wed, 23 Jul 2003 20:38:59 -0400
X-Message-Number: 45
MOST laptops work just fine direct on modern cars. A 12-14 volt input
laptop is 99% sure to work fine.
However, outside that range is an issue. My IBM ThinkPad for example is
'spec' at 16v, but works fine from 14 to 18 with no problems. It even
handles load dumps in the vehicle just fine. Below 14v input though it
gets hot. Drop below 13v sustained, and the internal switcher seems to
have trouble and it gets hot. Other than that, it's fine.
I've used MANY laptops in the car. Just fine. How many? I used to work
for SystemSoft, and then Insyde. I took almost every sample I could and
ran them in the car, either with GPS or as games for the kids on trips. On
trips to the parents house in PA from MASS we'd almost always have multiple
laptops running in the back for the kids. I'm just glad the kids got tired
of DOOM. And then there was this Rabbit thing... When a new laptop came
along, I'd trade it in and grab another.
If people want a list of all the laptops I've run in a car, I can guarantee
you it's over 40 or 50 different units. Trust me, if it had a SystemSoft
BIOS in it, or an Insyde BIOS, or had SystemSoft stuff like CardBoot or
other custom stuff (like HP 530, 540, 600, 800 series, or DEC Hi-Notes, or
IBM ThinkPads from the 700 series on) and it had a 12-18v spec on the
input, I tried it in the car.
In fact, the only one that really gave me issues was the Compaq LTE-5000,
and at the time I had that as 'my' machine, it was a prototype. I never
got a 'production' unit. It seemed to work just fine in the car, as long
as the car was running and it STAYED running... (Without a battery in the
unit. With the battery, it wasn't a problem. Although (it's been a long
time) I think there was an issue with the unit charging the internal
battery on vehicle voltage.)
Yes, going through the manufacturers DC adapter is always the recommended
way to go. But just using an inverter is not always. I've seen inverters
CAUSE more problems, when plugging in directly works fine.
As to an AC inverter and then back to DC, that's also iffy. Too many of
the inverters just don't output a clean enough sine wave, and some of the
laptop switchers have problems.
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Subject: RE: RAgeo, a low cost GEO bird
From: Bob Bruninga <bruninga@usna.edu>
Date: Wed, 23 Jul 2003 20:42:53 -0400 (EDT)
X-Message-Number: 46
On Mon, 21 Jul 2003, Brian Webster wrote:
>Bob,
>Just thinking off the cuff at this idea, would it be possible to
>also make some sort of passive microwave repeater.
No. If you want to experiment with that technique, try bouncing some
packets off of airplanes. It takes an EME class station only at a few
tens of miles...
But is easy to see the effect. Point a high gain beam towards a 300 mile
distant city along an heavily traveled airline path. Tune to a known busy
repeater in that city... You may hear it comne in from time to time for a
few seconds and it will fade in and out according to the multipath...
Bob
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Subject: Re: Trucks with 7 and more Wides
From: "Eric Christensen" <kf4otn@earthlink.net>
Date: Wed, 23 Jul 2003 20:51:11 -0400
X-Message-Number: 47
I have a guy near me that has a weather station and his home station
running WIDE,WIDE,WIDE3-3. I asked him to explain why the creative
path and he couldn't... Only that he felt it was necessary. Now, to
me this path doesn't make any sense... There is an I-Gate within
simplex range and another I-Gate within three hops... Anyone figure
this one out??? Did I also mention that the local digipeater is sent
out WIDE4-4?
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Subject: Re: Mobile power
From: Bill Owens N2RKL <bill-tapr@owensfamily.org>
Date: Wed, 23 Jul 2003 20:55:29 -0400
X-Message-Number: 48
On Wed, Jul 23, 2003 at 11:24:43AM -0700, Scott Miller wrote:
>I've got a laptop with a thrashed screen and no battery - I think I'll try
>hooking it straight up to 12 volts just to see if it'll power up. Now if
>only they'd use something more rugged than coaxial plugs for power.
I have an old 286 laptop that I keep around as a serial console (honest -
I'm going to use it tomorrow to set up a new network PoP) and its power
connector went bad a while ago. I opened it up, removed the coaxial jack
and soldered on a ~18 inch piece of heavy zip cord. Some wire ties for
strain relief, a Molex socket on the end and a matching plug for the
power supply, and away we go. That way I can also use the nice 12 VDC
computer power supply for my portable radios - in fact, it is powering
my APRS home station right now. I've since converted some of my radios to
the Connectors Which Must Not Be Named, and those would work just as well.
Bill N2RKL
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