[aprssig] APRN Info Needed

Stephen H. Smith wa8lmf2 at aol.com
Sun Dec 11 22:30:59 EST 2011

On 12/11/2011 8:47 PM, David Sprangers wrote:
> John and Stephen,
> Thank you for your replies to my questions and have cleared up a couple of 
> them. The one question I do have left is if I want to use my Kenwood TM-700A 
> for mobile SSTV, can I hook up the Argent Data camera to the 6-pin mini din?

Yes. Actually the so-called "data" jack is just radio AUDIO AUDIO AUDIO in and 
out --- not data in the sense of DC logic levels such as TTL or RS-232 signals. 
Full details on the 6-pin "data" or "packet" jack here on my website:P

. <http://wa8lmf.net/

> If the answer is yes, how do I configure the radio for this?

There's nothing to configure in the radio really. Analog SSTV is just 
frequency-modulated audio tones in the range from 1200 to 2300 Hz. So-called 
"Digital" SSTV", generated by the EasyPal program, uses 16 or 64 QAM audio 
sub-carriers in the range from 500 to 2200 Hz, in a manner similar to "56K" 
modems. In either case, you treat it as just another audio source to go into 
the radio. You would just connect the audio out and PTT lines from the Argent 
device to the TX audio and PTT pins of the mini-DIN. When the din's PTT line is 
asserted, it automatically mutes the voice mic input and keys the radio.

Note that on the D700, the 6-pin mini-DIN "data" jack follows the side of the 
radio selected for mic operations. There is no way to lock it to one side or 
the other of the radio.

> John,
> I am wondering if it would be possible to update your site with a comment how 
> the Kenwood’s VHC1 has been discontinued and listing a possible alternative 
> to the VHC1?

Except for Argent's SEND-only SSTV gadget, there really_IS NO_ replacement for 
the VC-H1. You are stuck with using a Windows PC of some sort to generate or 
receive SSTV.

> This is where I got lost about the setting up the Kenwood TM-700A with a SSTV 
> camera.

Except for the Argent Data device, there is currently no such thing as a 
dedicated "SSTV camera". (Decades ago, before PCs became ubiquitous in ham 
shacks and everything started being done with smoke, mirrors and software, 
there was such a thing.) Currently, the only way SSTV gets sent is via image 
files previously created by digital still cameras or scanners, or frame grabs 
from fast-scan video via computer capture cards.

I have been wrestling with this issue for the past 10 years or so, trying to 
come up with the least kludgy and distracting approach to a mobile "LiveCAM". 
The VH-H1 was unique in this ability to frame-grab single frames of live NTSC 
fast-scan video from CCTV cameras or the monitor out of digital still cameras, 
though it had severe software bugs and limitations.

If you ever happen to see a "Tasco 70 Scan Converter" at a ham fest flea market 
or swap meet, grab it as fast as you can. This device was a dedicated hardware 
NTSC<-->SSTV converter built around the same chip as the VC-H1. It had a BNC 
input for an NTSC camera, and a composite NTSC output on a second BNC for a 
monitor or composite VIDEO-IN jack (i.e. yellow RCA) on a TV. The other side 
was a pair of audio jacks to connect TX and RX audio to the radio. You can plug 
any off-the-shelf CCTV cam including the infrared-led-illuminated night-vision 
security cams into it, or the NTSC monitor output present on many digital still 
cameras. All in a box about the size of a KPC3 TNC that would run on 12 volts. 
Some of the newer car navigation system GPSs, both built-in and standalone like 
Garmin Nuvis and AVmap units now have an NTSC analog input intended for a 
backup camera. This input could also function as a monitor for the TASCO device.

> I would like to use my HP tc-4200 tablet pc for this potential project using 
> Windows 7. Currently, I am using this laptop with a SiganaLink SL-1 running 
> AGW.I have tested both WinPack and UI-View with Precision Mapping 9 without 
> any problems. I would think this tablet could handle the SSTV and related 
> software.

The main issue would be how does the touch-oriented tablet handle the rather 
fussy mouse-oriented user interface in both mmSSTV and EasyPal.

Does it have a built-in webcam? If so, you should be able to even originate 
live SSTV images. For digital SSTV,. EasyPal has a built-in TWAIN link that can 
acquire images directly from any camera or scanner-like device. (I help the 
author debug and beta-test this feature.) For the analog mmSSTV, you will have 
to TWAIN the webcam into some other graphics app such as IrfanView, and then 
copy/paste into the mmSSTV transmit window. (I have been asking for TWAIN 
support inside mmSSTV for a couple of years now, but so far no luck.)



Stephen H. Smith wa8lmf (at) aol.com
Skype: WA8LMF
Home Page: http://wa8lmf.net

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