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ZL3AI > APRDIG 10.05.04 19:43l 242 Lines 11056 Bytes #999 (0) @ WW
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To : APRDIG@WW
Subject: Re: Kenwood radios [was Re: APRS greater precision]
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 21 Apr 2004 11:33:14 -0700
X-Message-Number: 18
>The fact that no other manufacturer has offered an APRS-capable HT seems to
>say more about what the manufacturers think of APRS in general. Of course
>now, if you want location finding, you can buy a Benefone in the rest of the
>world (the US always lags) or a service like AT&T's "Find Friends" and track
>other cell phone customers on your own cell phone or computer. Not quite the
>same--but similar to APRS, and deployed on the "national 850 and 1900MHz
>repeater system". There's interest, and people are buying it. They're just
>not hams, not buying APRS.
And for an even more similar application, look at Garmin's Rino FRS radios.
They seem to be very popular. I'll bet they sell more of those in a month
than Kenwood has sold of the D7 and D700, ever. SAR people love 'em. Well,
some do, anyway. The limited range is a major drawback.
The big differences are the integrated GPS receiver and the mapping display.
The GPS receiver would be easy enough for a radio manufacturer to manage,
but for the mapping display they'd probably be stuck licensing it from
Garmin or one of the other GPS manufacturers.
Anyway, the Rino is a good example of what an AVL-capable handheld radio
should be. I've never seen how the D7 could compete with that, when you
consider the clutter involved and lack of useful display. Direction and
distance is a good start, but especially when you're dealing with multiple
stations it's not going to be easy to get a clear picture of where
everyone's at.
Scott
N1VG
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Subject: Re: Kenwood MObile APRS
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 21 Apr 2004 11:39:00 -0700
X-Message-Number: 19
>Suppose I send my primary in "APRS1.0" form, and alternate transmissions
>with every alternate sending in "APRS3.0" format instead? The old equipment
>gets to read half my squawks, the new equipment gets them all. An event
>organizer can choose which to support as needed.
The OpenTracker does this with a bit less channel overhead by sending the
two frames together. OpenTRAC data is tagged with PID 0x77, so it's not
seen by APRS and doesn't need to be otherwise differentiated. Since a lot
of your air time is wasted in transmit delay and preamble, by sending the
frames back to back separated by a single FLAG byte you're only adding maybe
20% to the actual channel usage, rather than 100% if you were to send both.
I understand that in the scheme you're presenting, it'd be alternating.
Assuming you're only decoding one version, the end result is that you've got
to double the beacon rate to get the same number of positions decoded.
Whether you intend for that to happen or not, that's what people are going
to do.
Scott
N1VG
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Subject: Re: Kenwood radios [was Re: APRS greater precision
From: "Stephen H. Smith" <WA8LMF2@aol.com>
Date: Wed, 21 Apr 2004 11:56:43 -0700
X-Message-Number: 20
KC2MMi wrote on 4/21/2004, 10:57 AM:
>The D7
>does many things and APRS is just one of them. Kenwood's "SKY COMMAND"
>and
>SSTV features are also packed in that radio. It seems to be their
>"let's see
>what else an HT can do" product, not at all a dedicated APRS toy.
1) The D7/D700 have no "SSTV features". They do absolutely nothing for
SSTV that can't be done from the VC-H1's own front panel. The menus in
the D7/D700 only duplicate functions already selectable from the VC-H1
front panel. Controlling the VCH1 from the radio requires connecting
TWO cables between the D7 and the VC-H1 -- one for TX/RX
audio/push-to-talk, and a completely diferent one for control functions
via the radio serial data port. A real kludge.
The only significant "support" these two radios offer for SSTV is audio
inputs and outputs; i.e. support for a speaker mic in the case of the D7
and the MiniDIN6 accessory connector in the case of the D700.
>On those three scores, they've dropped the SSTV unit, no idea why.
2) The VC-H1 had glaring deficiencies that limited it's appeal,
including an appallingly bad camera/imager that totally overloaded in
daylight and no way to force the unit out of the lousy low-res Robot36
transmission mode except by hearing an incoming transmission in a
higher-quality mode first.
The final coup-de-grace for the unit was that the unbelievably bad and
clunky external control software required to upload/download images from
the device to/from a PC. The program only works under Win95/98. When
the NT-based Windows XP became the mainstream consumer operating system,
Kenwood killed the hardward product rather than commission a new version
of the support program.
I have two of the VC-H1s; this problem with the support software means I
have to maintain dual-boot Win2K / Win98 installations on my PCs
indefinitely.... I have not yet found any compatibility fix that will
allow either Kenwood's own software --OR-- the decent third-party
PixTK-2000 support program from VE4RZ to run under Win2K or WinXP.
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff http://members.aol.com/wa8lmf/aprs
Personal APRS WebServer http://members.aol.com/webserver
----------------------------------------------------------------------
Subject: Kenwood radios [was Re: APRS greater precision
From: "KC2MMi" <kc2mmi@verizon.net>
Date: Wed, 21 Apr 2004 15:16:55 -0400
X-Message-Number: 21
Stephen-
<1) The D7/D700 have no "SSTV features".>
The D7 has menus regarding SSTV setup options. It expends some memory on
these. In that sense, if the programming data for the VC-H1 is being stored
in the TH-D7, the D7 already "requires" onboard memory and other components.
My point is that once you have an alphanumeric display, a processor, and a
storage area, it is possible to simply "add more stuff" in unused space on
them. If the D7 has a kilobyte of data storage area using a 1024-byte
storage chip (just a random number!) and the VC-H1 data only occupies 256
bytes in that chip...
...Someone in marketing or engineering is going to say "Hey, three quarters
of this chip isn't being used, can we stuff something else in there?" and
someone might say "Well, we don't we see if they'll buy APRS? We just need
to write some more software."
Maybe there's more to it than that. That's immaterial. My point is that
SOME real estate in the radio already is committed to other features, and we
can only guess which ones were the reason Kenwood built the radio.
For all we know, "Mister Kenwood" wanted an APRS radio to track his dog,
and the rest was added to it.<G> After all, Sony's widely popular "Walkman"
was designed solely because the head of Sony wanted a tiny player for his
personal use.
It would be very interesting--and topical--to find out what Kenwood had to
say on the conept of APRS and how that has affected, or fit into, their
marketing plans. A view from the business side, rather than from the hobby.
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Subject: Re: APRS-a Newbie's Perspective
From: "Curt, WE7U" <archer@eskimo.com>
Date: Wed, 21 Apr 2004 13:02:14 -0700 (PDT)
X-Message-Number: 22
On Wed, 21 Apr 2004, Clair Dunn wrote:
>In the light of Amateur Radio Public Service, Scott's needs in SAR come
>first. His ia practical issue, not a theoretical one. People need to be
>found.
Nothing that's been said on the list in recent days will stop Scott,
myself, and other SAR/CAP/RACES/ARES people from using APRS for what we
need. Some of the suggestion could really help us though if implemented.
Personally, I started out with the gee-whiz novelty of APRS, but then
joined SAR 4 years ago, and my interests changed. Now that's what I'm
trying to tie together, by pushing a square peg into a round hole. Luckily
I can add/change features in at least one APRS program to suit my purposes,
and am continuuing to do so.
>And here we are back to the practical information. And, I have one
>suggestion for a solution. And please don't groan when I suggest yet
>another web site. Because that is what I am suggesting. However, there
>is only one kind of document that will appear on this web site. Everyone
>currently using APRS needs to write up their *exact* station:
>
>1. equipment - brand names, models, years of manufacture
>2. software - version (compatibility issues if available)
>3. necessary cables
>3. wiring connections - what goes to what in specific terms
>4. ALL SETTINGS which are applicable to making things work, tone
>setting, frequencies, shifts, modes, etc.
>5. laptops used (battery issues -- how long), processing spedd, memory,
>screen resolution, maps used, etc.
>6. any special issues, problems
That could very easily be handled by a Wiki page. Here's an example:
http://www.findewe.com/nwaprs/SearchAndRescue
Have something useful to add? Add it!
Perhaps someone will devote a Wiki site to doing what you propose.
>One question I have: how fast does the computer have to be? Is there a
>way to have zoomable maps loaded only for your local area, separate from
>the entire wide area? Surely if this were possible, less processing
>speed and memory would be necesary??
I've run Xastir/Linux on a 486 laptop. You'd probably want at least
a P90 these days, but I run it on a P133 with 64MB of memory in my
Jeep, and it does ok. It should still work down to a 386SX-16, but
you'll have to wait a while for maps to show up.
>Ummmm -- another website possibly. One for APRS folks who have the money
>to buy the latest and greatest, who can then sell their old equipment to
>new APRS recruits via truly informative ads!!!
Wiki would work again, although I'm not sure that's the best configuration
for buy/sell stuff.
>And, yes, I could have gotten the Kenwood with the money I've spent on
>the WX station and the KAM+, but then, with almost no other tracking
>staions in my area, of what use would it be? My old 75MHz laptop is too
>slow (I think) to be of any use, but I'm sure going to experiment with it!
You could have saved more money by going with Linux (free), Xastir (free),
and maps (free) on that old hardware, then used the extra money for your
weather station, radios, TNC's, and GPS. From your description of being
somewhat tenacious, you shouldn't have any trouble setting things up.
--
Curt, WE7U archer at eskimo dot com
Arlington, WA, USA 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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