am..Brew

73 Review by Terry Churchfield K3HKR
Number 9 on yotlr FNd~ k uord
Amiga A VT System
SSTVand FAX like you've never seen before!
Advanced Electronic Applications
PO Box C·2 160
l ynnwood, WA 98036
Price Class: 5300
Slow·scan TV ($ S TV) has been a specialty in
ham radio, practiced by a small group tesonsted
by the idea of sending video images
worldwide on the HF bands. The practice of
this mode, however, has been plagued by
many problems-the expense of dedicated
equipment, the susceptibility of the image to
band noise and interference, and the lack of
frame resolution, to name 8 few. The subject
ofthis review, however-the Amiga A VT interface,
conceived by Ben Blish N4EJI-uses
digital techniques for dealing with slow-scan
signals and images with aston ishing reo
suits ...deNS'S
A. Are you considering trying slow-scan
television (SSTV)?
B. Would you like to receive FAX images for
weather and news?
C. Do you think that SSTV is nol worth Ihe
time, energy, or radio spectrum?
D. Areyou lOOking into buying a new computer
lor business, home, andlor shack?
E . All 01the above?
F. None ol the above?
Even if you answered " F" 10 th is simpl e
multiple-choice questionnaire, you owe it to
yourself to read on!
Life After 20m sse
Hams with the least amounl
of curiosity can't help but want
10 experiment with exotic
modes, such as FA X and
SSTV. We soon hear, however,
how expensive and um e-
consuming it can be to get involved with
them. We couldn't afford. nor talk our wives
into, buying equipment dedicated 10 SSTV
or FAX.
Renewed hope came along with the growing
availabuity 01 personal computer systems.
This was something the whole family could
use. Mosl Pes, however, are not designed lor
high quality graphic output. One recent newcomer
is a cremate exception...
The Amiga Computer
In 1985, Commodore Business Machines
introduced a new computer using a microprocessor
capable of true 16-bit addressing.
T h is computer h ad the most advanced
graphic co-processors 01 the time and true
multitasking capability. Multitasking is the
capability of a computer to run two or more
program s concurrently. (Programs " ti me-
Photo A. The AVT Interface board .
share"
th e CPU in tightly-timed cycles.)
This was a breakthrough lor p e rsonal
compulers.
The Amiga is capable 01 runn ing MS-DOS
programs, so I could upgrade to the Amiga
and sun use my PC software. With a few inexpensive
eoc-cre. I can run e-64 or Macintosh
software. Because of multitasking, I could. lor
example, operate packet on the PC side and
use my word processor on the Amiga side at
the same time . The packet information can be
saved as an MS·DOS file that I could use in my
documents on the Amiga.
The Amiga's true NTSC composite video
allowed animation, c haracter generation.
and high quality image art output 10 my VCR.
I taped weddings. hamfests, and company
picn ics. and added graphics and unes to my
home VCR movies. This $1600 investment
- which comprised an Amiga A2000 mcro-
Photo 8. The AVTcontrol panel, on lower halfofphoto.
Photo C. The AVT control panel with I/O window open. The siK icons on
the screen are coupled to the siK inputjacks on the A VT interface board.
73 AmateurRadio • July,1 989 29