[aprssig] APRN news from Dayton!

Sun May 22 20:25:50 EDT 2011

On 5/22/2011 5:33 AM, Bob Bruninga wrote:
> Exciting news for the Automatic Picture Relay Network (APRSN).
>
> Since the handheld SSTV/APRS camera transceiver from Kenwood has not been in production for years, there has not been much APRN growth.  But now at Dayton, ARGENT Data Systems (Maker of the APRS Opentracker2) has introduced a tiny golf-ball sized SSTV camera (outputs Robot mode).

Do you mean he has now encased the naked SSTV cam shown on his website at:

<http://wiki.argentdata.com/index.php/SSTVCAM>     ?

Why do you want to use the absolutely awful Robot modes?   The resolution is 
horrible and really not useable for any kind of serial photo documentation of 
disasters or anything else.  Fine details (parallel clapboard siding, fences 
with parallel wires, overlaid text,etc) aliases into shimmery rainbows of 
colored fringes on contrast lines.

Unlike the Kenwood VC-H1 which defaults to Robot 36 until it HEARS a 
transmission in another mode, the Argent device can be forced to default to the 
vastly-superior Scottie modes.

> Every APRS ham in emergency response should have such a camera for instant image reporting from the field.

The problem is that there is no display of what the camera is seeing, or any 
way to focus.

Is a normal NTSC output available from the camera daughter board?  My Garmin 
Nuvi 855 has a NTSC video input intended for a car backup camera.  The 4.3" 
Nuvi screen could make a really nice viewfinder for the "mobile LiveCAM" if the 
device has an NTSC output.

>   For those not familiar, the way APRN works, is that you snap a picture, tune to the local APRN input frequency,

Of which there are about 2 in the entire world.....

> then TX from your handheld, followed by your APRS radio's packet report which identifies who, what, when,where, why, etc about the picutre.
>
> The APRN site, then catalogs the image using the APRS STATUS packet info so that all local response personnel can see it (as well as everyone else in the world!).
>
> Please see WA8LMF's APRN site:
> http://wa8lmf.net/aprn/
>
> APRS, Kenwood,

And Kenwood then bungled the product       a) by using a camera head with 
insufficient auto light-level control that grossly overloads in broad daylight 
(i.e. essentially only usable indoors) and     b) with the incredibly awful, 
buggy, clunky support software provided with the VC-H1.  The final 
coup-de-grace to the VC-H1 is that all versions of the support software for 
this device absolutely positively won't work on Win2000, Win XP or later.  The 
three versions of the software Kenwood issued for this device ALL used a 
communications control library incompatible with NT-based Windows, as did the 
two third party alternative apps for the VC-H1 & Tasco scan converter.

When XP superseded Win98 as the mainstream OS on consumer PCs, the VC-H1 was 
killed rather than update the junk software.     (I maintain a Win98 virtual 
machine inside my Win XP machines solely  to run the VC-H1 upload/download 
software.)

> and APRN were years ahead of the cellphone camera, now we're back!

Back at about   1/50th (!)    of the resolution of current cellphone cameras.

The SSTV image is 320x256 pixels (quarter VGA) for a total of  81920 pixels or 
(drum roll)  .081 megapixels.

Compare to the  3-5 megapixel resolution of current  mainstream cellphone cams....

One can achieve a VASTLY better live SSTV system by using a $225 Asus or Acer 
netbook.   These lightweight (about 2 lbs) devices are full Windows PCs with 
Ethernet and WiFi connections, a sound system and a 120GB hard disk or larger.  
The netbook's built-in Webcam is full VGA resolution (640x480 pixels) or 
higher. A simple pair of audio cables can connect the netbook's sound system to 
the TX/RX audio of a radio.

I have an Acer ZG5 netbook running soundcard packet for APRS --AND-- mmSSTV for 
SSTV send (AND RECEIVE!) on the same sound card.  (It seems to be a well-kept 
secret, that since Windows XP, more than one app at a time can access the sound 
card as long as they both use the same sample rate.)

My configuration has AGWpe (soundcard soft TNC), UIview and Precision Mapping 
(allows quickly and easily editable comment fields and status messages for 
APRN) and mmSSTV running at once.   Unlike the VC-H1, you can run ALL the SSTV 
TX/RX modes including ones that can send 640x480 pixel full VGA and 600x800 
pixel SVGA images.    Further, mmSSTV can send/receive the MP73-N SSTV mode 
that is only 500 Hz wide, and is legal on the data-only 30-meter band!

For a "LiveCAM" shot, you just hold the netbook in one hand, and point it's 
built-in web cam at the target of interest. You can see live (fast scan) 
full-motion video in a monitor window before grabbing a single frame for 
conversion to SSTV.

I am now playing around with combining Chris Moulding's soundcard-based APRS 
Messenger application with MP73-N narrow SSTV for an APRN solution for 30M HF. 
Again, both apps can share the same sound system at the same time.

Or if you really want send hi-quality pics,  VK4AES's EasyPal "digital SSTV" 
system will run on these mini PCs.  This program is actually a generic binary 
file transfer program embedded in an SSTV user interface, and can transmit any 
kind of file guaranteed error-free.  The program encapsulates JPG images (or 
Word documents, spreadsheets or any other kind of file on your hard drive) in 
TWO layers of forward-error correction encoding.   It then transmits them with 
4, 16 or 64 QAM audio subcarriers (depending on the bandwidth of the radio; 
i.e. FM or SSB) in a manner similar to a "56K modem".   The program has TWAIN 
links that can capture images directly from a digital camera, scanner or the 
netbook's built-in webcam.

Like most digital transmission systems (such as our newfangled ATSC digital HD 
TV), you either get a perfect image --or-- nothing at all. The EasyPal  
transmission is broken up into multiple independent blocks.  If some blocks are 
defective at the receive end, the program on the receiving end can ARQ and 
request just the retransmission of the bad blocks.   The ARQ requests can even 
be answered by a third-party bystander station that happened to get the 
required blocks successfully.

I have actually had this experience transmitting on 40 and 20 meters from my 
mobile on Interstate 70 in Utah and Colorado.   As you drive through the 
canyons and mountain passes of I-70, HF propagation is constantly being blocked 
in ever-changing directions. (Deep canyons mean only high-angle short hop 
radiation gets out) Typically no single station will get an entire transmission 
on the first try  I have made EasyPal SSTV LiveCAM transmissions that were 
partially received by two or three different stations.   With several station 
issuing NAKs for missing blocks, and other stations responding to ARQ requests 
for the blocks they DID got,  all stations ultimately get the picture perfectly.

I have had mmSSTV (for analog SSTV) and EasyPal (for digital SSTV) running 
simultaneously on the sound system of a Dell 866 MHz Pentium III, along with 
the AGWpe packet app for a complete entirely software-based APRN dual-mode 
(analog + digital) receive setup.

-------------------------------------------------------------------------------

--

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

=====  Vista & Win7 Install Issues for UI-View and Precision Mapping =====
     http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7

*** HF APRS over PSK63 ***
    http://wa8lmf.net/APRS_PSK63/index.htm

"APRS 101"  Explanation of APRS Path Selection & Digipeating
   http://wa8lmf.net/DigiPaths