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ZL3AI > APRDIG 25.09.03 09:40l 213 Lines 9729 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Sep 22, 6/7
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Re: Excessive Paths - WIDE5 (NEW IDEA)
From: Mark Cheavens <mcheavens@usa.net>
Date: Mon, 22 Sep 2003 18:11:34 -0500
X-Message-Number: 34
Bill,
I would agree that this is the IDEAL solution. But as I stated, we need to
try and work towards an interim solution that is CHEAP to implement for the
installed base.
A small footprint computer that can be configured via remote that would
work in KISS mode would also help as a NEXT step.
(this would work with Digi-Ned NOW!)
Mark Cheavens
KC5EVE
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Subject: RE: Take Control of your DIGI
From: Bob Bruninga <bruninga@usna.edu>
Date: Mon, 22 Sep 2003 19:31:25 -0400 (EDT)
X-Message-Number: 35
On Sun, 21 Sep 2003, Scott Miller wrote about the concept of turning off
WIDEn-N in some digipeaters that better serve local communities:
>I think the idea makes sense. There has to be a distinction between
>'border' digis and those serving a local area - an autonomous system, in
>BGP's terminology. The problem around here is that the border digis are
>basically the entire system, at least with W6AB off the air.
Yep, it aint gonna be easy, but at least now we have a tool, that is
already in all of our hands to think about how we can use our digi
structure to differentiate between long-haul needs and local needs.
>Once SAR really starts using APRS, though, it's going to be a much bigger
>deal, to keep the LA-area traffic out of the local network.
>
>BTW, if anyone's interested, I've done quick plots of coverage for K6TZ-10
>(at its new location over Santa Barbara) and K6SYV-10 (still on Figueroa
>Mountain). They're at http://www.n1vg.net/k6tz-10.jpg and
>http://www.n1vg.net/k6syv-10.jpg. K6TZ-10 was just moved in an attempt to
>provide better back country coverage for SAR, but I don't think it's going
>to work as well as the operators were hoping.
Good luck. It is quite a puzzle to figure out. A challenge. I just
looked around me (Maryland) and there are 4 digis in my 32 mile Aloha
circle. But going out to the 64 mile range scale, there are 16. Trying
to figure out which ones should do WIDEn-N is a daunting task.
BUT, when I looked at raw packets last night, I notice a VERY SIGNIFICANT
thing! 90% of all packets on the air aren't WIDEn-N in the first place!
Most of them are WIDE,WIDE. I guess since the mid-atlantic where APRS was
born just never really upgraded to WIDEn-N (though most digis support it).
But this is a lesson in itself, which shows that many old dogs just wont
learn new tricks either...
No answers, just observations.
de WB4APR, Bob
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Subject: Re: Take Control of your DIGI
From: Bob Bruninga <bruninga@usna.edu>
Date: Mon, 22 Sep 2003 19:46:13 -0400 (EDT)
X-Message-Number: 36
On Sun, 21 Sep 2003, Jim Sanford wrote:
>...I just moved to SW PA (Eighty Four, SW of Pittsburgh.). I'm at 1300'
>ASL, which is about as high as anything close, and I hope to put up a
>100 foot tower. Was planning to put up a RELAY, and possibly a WIDE,
>depending on what the locals tell me we need. I note that sitting in my
>1250' driveway, I get into the system, and within 5 miles of my office
>in Monroeville (E of PIT), I get in, but between, coverage is very
>spotty. Clearly, some help is needed.
That says it all. I'd put up a WIDE (without WIDEn-N) and see how it
works. If you get lonely and feel that you want bring in some WIDEn-N
mail from the long haul, then simply put up a WIDEn-N digis that LISTENS
on 144.39 but TRANSMITS on UHF. Then to feed your addiction to WIDEn-N,
just tune in th4e UHF freq...
de WB4APR, Bob
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Subject: WIDEn-N to-UHF path splitters
From: Bob Bruninga <bruninga@usna.edu>
Date: Mon, 22 Sep 2003 19:54:29 -0400 (EDT)
X-Message-Number: 37
Someone asked: "If you cut off WIDEn-N at the borders, then how does that
traffic get into the city?"
EASY! Just take that WIDEn-N border digi, and let it continue to LISTEN
on 144.39. But connect its TRANSMITTER to a UHF transmitter!
Then anyone that wants to monitor the LONG haul and see hundreds of users
from all over, can tune into that UHF frequency. But it keeps it all off
of 144.39 in the city. If that site is also needed as a WIDE, then you
may have to have two TNC's. One with the cross band for the WIDEn-N, and
one normal WIDE...
Better idea. If DIGI-NED or UIDIGI authors could simply add an OUTPUT BIT
to their TNC code, that used the NORMAL PTT for all RELAY/WIDE digipeated
packets, but then keyed this SECOND PTT for only WIDEn-N traffic, then the
one TNC could do both jobs. That is playing traffic cop to route packets
as needed.
I'll send this idea to Kantronics. (or whoever will listen)...
Wow, listen to all local WIDE,WIDE or RELAY,WIDE traffic on 144.39, but if
you want to see the rest of the saturadted APRS long-haul stuff, just tune
in the local UHF freq... Hummh...
de WB4APR, Bob
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Subject: Re: SSTV WAS: Excessive Paths - WIDE5
From: WA8LMF2@aol.com
Date: Mon, 22 Sep 2003 19:57:45 EDT
X-Message-Number: 38
In a message dated 9/22/2003 2:33:30 PM Pacific Daylight Time,
scott@opentrac.org writes:
>SSTV would be a cool capability to have. Is there such thing as a cheap
>SSTV encoder? I'm not sure how sophisticated the signal is, but it'd be
>pretty cool to build a box that plugs into a cheap QuickCam or something
>similar and would snap and encode a frame when you push a button.
Today about 99% of SSTV operation is done with PC soundcard software. No
especially extreme PC capabilities are required -- anything that is a
Pentium 166 MMX or higher with sound system should be enough.
The only standalone hardware SSTV devices being used at all today are the
Kenwood VC-H1 handheld and the Tasco 70 scan converter. Both of these (now
- discontinued) devices are based on the same proprietary VLSI scan
converter chip and have similar capabilities. On one side is audio in/out
to the radio's mic and speaker connections. On the other side is input for
standard analog NTSC composite video from a TV camera, cam-corder, VCR,
etc, and a composite NTSC output for a TV monitor or
base-band-direct-in equipped analog TV.
The VC-H1 combines the scan converter with a 1.8" LCD color monitor and an
unbeliveably bad CCD camera head into an battery-powered oversized
speaker-mic assembly that can be used with any radio. Jacks on the device
allow the use of external monitors and video sources.
The Tasco is packaged in a box similar to, but slightly larger than, a
KPC3 TNC with BNC connectors on the back for the video input and output.
Both devices frame grab a single 262-line fast-scan field (not an entire
frame) by digitizing it on-the-fly and clocking it into static CMOS ram.
The data is then played out of RAM at the SSTV transmission rate (anywhere
from 30 to 90 seconds depending on mode). The single field capture, which
is triggered by pressing a still-camera-shutter-release-like button, is
more than adequate since the standard SSTV modes are only 240 lines by 320
pixels/line. I.E.; in this multi-megapixel-crazed digital camera era, a
whopping .076 megapixels!
The two devices also have a serial port that allows you to download the
digitized still image as a BMP or JPG to a computer. The two devices are
so similar at the software level that the same upload/download utilities
will work on both the VC-H1 and the TASCO.
WARNING! The (now orphaned) software that does this only works on
Win95/98. All three of the available utilities to do this are completely
non-functional on Win 2000 and XP. I suspect that the need to completely
redo the associated software, to deal with Windows XP, is part of the
reason Kenwood discontinued the VC-H1 last December.
The "cheap QuickCAM" would produce about as awful an image as Kenwood's
provided camera head. The problems are:
1) An excessively wide-angle view that makes it very difficult to get
anything in the image large enough to be clearly visible given the low
resolution of the SSTV frame; i.e. you get the equivalent of a 30-35MM
focal length on a 35MM SLR from these cheap cams.
2) Totally inadequate video dynamic range and contrast handling for outdoor
use. The automatic light-level control (if there is any) is only suitable
for interior lighting levels -- the images from these simple cams wash out
and overexpose hopelessly in direct sunlight.
Which is why I always use a good external digital still camera in my
"mobile LIveCAM" setup. It consists of a VC-H1, with it's own camera head
removed, connected to the NTSC monitor output of a Sony digital still
camera mounted on the dash of my car. I also use the VH-H1 as the mic for
my mobile radios. When I see something interesting in the LCD monitor of
the camera, I press the frame grab button of the Kenwood. At some time
later, I can press the transmit button on the VH-H1 to actually send the
pic. The VC-H1's internal CMOS static memory will store up to 10 captured
or received images for later transmission or upload/download to a PC.
APRN Mobile LiveCAM http://members.aol.com/wa8lmf2/aprn
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
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