Short history of the MTR’s ancestors (the ATS series) by the man himself.
Group: AT_Sprint Message: 2427 From: Steven Weber Date: 12/11/2007
Subject: Re: History of ATS series
The ATS series started out as a SMT project in an attempt to build a trail
friendly rig into an Altoids tin. It was built on two boards which plugged
in together, was a dual band 20/40 meter rig with relay switched filters.
The PA was a NPN SOT-223 device with a fairly low Ft, so power out wasn’t
very good, even at 12 volts. Maybe 2 watts on 40 and 1 watt on 20.
Besides the low power output, the most serious problem was mechanical. The
two boards were the same size and had common connections along both edges
of the boards. Both boards had to be connected together for anything to
work, so it was very difficult to trouble shoot if something wasn’t working
right. Longish jumpers had to be soldered between the boards so they could
be placed next to each other, instead of being stacked so it could be
worked on.
Dispite this, I put picutres of the rig on my then new web site on qsl.net.
It wasn’t long before I was getting requests to kit the rig. Since what I
had wasn’t real practical to kit or build, I went back to work on it.
The breakthrough which made the ATS rigs possible was the invention of the
square wave, logic gate driven 2N7000 PA. At last I had a PA which was
simple, took up little board space, was effiecent, had consistant power
output on different bands, worked at low voltages and used common,
inexpensive parts. The second innovation was to use the now familer band
filter module boards. I was now able to fit everything on a single board,
dispite using mostly 1206 sized passive parts.
As for functions, it only had the basics, because the processor used was an
Atmel 90S2313 with only 2K of memory. It had RIT, keyer with one memory,
Tune up mode, the push button tuning and frequency annunciation.
Only about 50 of the original ATS rigs were produced.
A year or two later, some new parts became available, or I became aware of
them, like the low power AD9834 DDS chip, the TI MPS430 processor and
LM4808 low power headphone amplifier. I decided to try these new parts in a
new ATS design to see if the current consumption could be significantly
reduced. The ATS-1 drew some 50 ma on receive, which was a significant
amount of current.
Thus, the ATS-2 was born. With the new parts, receive current dropped to a
much more modest 25-26 ma, half of what the ATS-1 took. I also made the
board much larger and put it in a plastic box which could also hold AAA
batteries. The larger board allowed parts to be spaced farther apart,
making it easier to build, adding a few slide switches and little volume
control.
With more memory available in the MPS430 processor, DFE mode was added,
along with XIT and the calibration modes. 80 meters was also added, making
it a 4 band rig, instead of just the three bands the ATS-1 did. (40/30/20)
About 100 of these were produced. I might have did more, but the plastic
box which was supplied had the front silk screened. This I did myself,
which turned out to be a mistake. Most of them turned out okay, but not
great. It was a lot of work. I resolved to go back to the Altoids tin
formate. While some liked the larger form factor of the ATS-2, most still
wanted the smaller Altoids size rig. Besides, the KX1 came out about then
and I wanted to have the smallest, lightest rig there was.
So, back to the Altoids sized rig with the ATS-3, followed by the 3A and
finally the 3B, each which had incermental improvments from things learned
from the previous design.
72,
Steve, KD1JV
“Melt Solder”
White Mountains of New Hampshire
http://kd1jv.qrpradio.com
