On-Line User's Manual
DSP10 2-Meter TRANSCEIVER
Bob Larkin, W7PUA & Mike Reed, KD7TS
Introduction
This is an amateur radio project, intended to
explore the use of
Digital
Signal Processing (DSP) as the i-f and a-f processing of a transceiver.
The primary application is weak-signal work on the bands above
2-meters.
Interestingly the transceiver also operates at 2-meters as presently
built
and can also be used on that band. Transverters are used ahead of the
transceiver
for the higher frequencies allowing operation into the microwave range.
The control and the front panel for the transceiver is any PC running
DOS
and having VGA graphics. The keyboard controls the transceiver. Status
information, along with spectral and signal strength displays, are on
the
screen. Audio comes from the DSP, not the PC. No internal sound card is
required.
Background for this project is available in the three-part
article by Bob
Larkin, W7PUA, "The DSP10---An All-Mode
2-Meter
Transceiver Using DSP I-F and PC Front Panel," QST Sept, Oct and Nov
1999,
and "A DSP Based Transceiver for UHF and Microwaves." This manual has
been assembled from the program notes for versions
1.6 , 2.0, and 3.0 of the software, that have long been available. In
addition,
material
that is new to version 3.94 of the program is also included. Thus this
document
is the basic operating manual for the transceiver. It does not include
the hardware assembly information, nor the software source code and
background.
That collection of information is quite extensive and remains available
from the Internet
Feedback -
Please email corrections,
comments
and suggestions to this manual to kd7ts 'at' comcast.net
Program
bugs
should be reported to W7PUA boblark 'at' proaxis.com.
A few highlights for Version 3.96
It has been my good fortune to be among the "beta"
testers and in
a location with active DSP-10 users. Operations have been on a daily
basis for a number of years on 10 GHz and recently 24 Ghz has been
added. To add to my good fortune, there are two local home
stations, W7LHL and
W7SZ to provide signals with their DSP-10 and transverter on 10
and 24 GHz.
The DSP-10 is a user configurable signal processing system that
can be used as a weak signal communications platform or as a tool for
investigating propagation. To make this useful as a tool,
accurate frequency is needed, also to be useful for weak signal
communications, accurate timing is needed. Frequency control is handled
by use of GPS disciplined 10 MHz references. In the recent past, time
was done manually, by the user, with whatever time source could be
pressed into service. Usually this is WWV and an HF receiver, but could
be anything available.
Time in the x386 architecture is a daunting task for the
programmer, and time accurate to the 55 millisecond level is possible
with some diligence. The clock in most Personal Computers is not
well suited to maintaining correct time for long periods. To overcome
this problem a
system
was devised by Johann, KC7WW, to switch the PC between the DSP-10
and a GPS interface. Bob, W7PUA wrote the code to incoroporate control
into the DSP-10 software based on Johanns routines. This provides
automatic time setting and update, or manual update using the NMEA0183
data and the 1 PPS from the GPS engine. The software also allows
switching by manually operated serial switch box, or even simply
reconnecting the cables between the GPS, DSP-10 and PC. GPS is
not a requirement for general use. The requirement of the TZ
environment variable has been removed for the PC and time is now all
done in GMT. The DSP-10 continues to perform using the original system
of time set with WWV etc.
The addition of the Clock and GPS routines suggested the
possibility of calculating distance and headings between
stations, and this has been added to the Version 3.80 control software.
Although the GPS was a motivation for the routines being added, it is
not a requirement.
Many improvements make the operation easier, and faster. One of
the
these is the DOS VISIT. This has been available in past versions, but
with the addition of dynamic memeory allocation, has made the use of
the hard drive more attractive as opposed to running from a floppy
drive. This is very useful to transfer screen saves (which save very
quickly on the hard drive) to a floppy while in the middle of a weak
signal QSO. This may have limited appeal, but has been very useful
locally.
Have fun !
Mike KD7TS
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