to the MSA Web Site,
the Modularized Spectrum Analyzer Interested
in owning your own RF Spectrum Analyzer ?
This site is dedicated as a Home Experimenter's Guide to building a
yet, Inexpensive 1000 MHz Spectrum Analyzer.
Original MSA, mated with a laptop computer. Not pretty, but works
The newer version, the SLIM MSA. Same concept, but constructed
using Standardized Laboratory Integration Modules, SLIM's. Updated Nov
1, 2013 Updated
software to Version 117. Download software from Initial
Set-Up and Calibration of the MSA The
MSA project was started in Jan,
2001 and has evolved under several titles. By Scotty
your own Home-Brew 1000 MHz Spectrum Analyzer, you already have
of it completed. That half is the computer
you are using to read this. The processors and displays are very
expensive portions of modern spectrum analyzers, and those
functions can be replaced by your home computer. The computer's
monitor is the
Spectrum Analyzer's display. The other half is the MSA hardware,
constructed (as seen in the photos).
The MSA Software is free to download. It will
operate on any computer with a parallel port, USB 2, or USB3 and
any Microsoft Windows platform. USB
operation has been tested using Win XP, Win7, and Win8.
to this Site will notice significant changes. I have deleted most
references to previous versions of the MSA and will concentrate on the
MSA using SLIMs, Standardized Laboratory Integration Modules. The
previous designs and web pages are retained in the MSA Archives, for those who need the
references. The SLIM MSA
not obsolete the Original MSA design. The Original MSA will
continue to be supported in the software.
title of this page and the opening paragraph seem to indicate
MSA is a Spectrum Analyzer with
operation limited to 1000 MHz. This was my original concept
goal. The computer would command the Spectrum Analyzer to a
specific frequency and display a received magnitude as
spectral graphics on its monitor. However,
software and hardware additions have allowed the MSA to provide many
more Functions than just that of a Spectrum Analyzer. The Functions
depend upon the level
construction. There are 3 Build Levels of the MSA.
Build Level 1: The
Analyzer (Level 1) is the core of the MSA Project It
is comprised of 11
modules and is common to all
higher levels of construction. Its basic function is that of a Spectrum Analyzer,
with these specifications:
3 band ranges:
1-2 GHz, and 2-3 GHz (or higher using harmonic
less than 3 Hz
Instantainous Dynamic range: greater
than 100 dB.
-20 dBm to -120 dBm
Optional, with Resolution
Bandwidth filter selection. When not used as an SA, the
Basic MSA can provide these other
Voltmeter (future development with A to D Converter)
Fixed, 64 MHz Clock Source,
50 ohm, square (Master Oscillator)
1-1.5 GHz, 50 ohm, sine. Selectable in steps.
Variable, 1-2 GHz,
50 ohm, sine, <3 Hz resolution. (PLO 1)
Variable, 0-1 GHz,
50 ohm, sine, <3 Hz resolution. (PLO 1 - PLO 2)
Variable, 2-3 GHz,
50 ohm, sine, <3 Hz resolution. (PLO 1 + PLO 2) CW or Swept DDS Signal Generator,
50 ohm, sine, 0.014 Hz resolution. (DDS 1)
MSA Requirements for the
Home Computer and its Software:
PC or Laptop Computer (any speed), with
standard or enhanced
port (SPP, EPP), USB2, or USB3 Monitor can be any
size, but MSA
800 by 600 pixel resolution. (I am using a Toshiba
Satellite Laptop, 700 MHz
Celeron, WinME, dual monitors: 15" and 19").
Windows 98 or later. MSA
software is executable, but builders
who wish to modify the MSA software will need Liberty Basic 4.03.
The Liberty Basic is
free, but it will nag you to buy it. Go visit their web
site at www.libertybasic.com.
Other Web Sites supporting the MSA Project Sam Wetterlin's Site, a Gold
Mine of information, containing some great items for the MSA, examples: Wide Band Leveler.
An AGC Amplifier
with constant output amplitude, for calibrating the MSA. 1 MHz Calibration
Source. Sine and Square Wave
Generator, for calibrating the MSA. OSL Standards.
Construction and explanation
for precision open, short, and load for use with the VNA. Attenuators.
Precision fixed and switchable attenuators. Reflection Bridges,
passive and active. For use with
the MSA/VNA. Test Fixtures. Series and Shunt
Test Fixtures. Used as
test bridges with the MSA.
Sam has written several documents supporting his
MSA/VNA. I will
refer to many of them: Title:
The MSA as a Vector Network Analyzer, 12/12/09. This is his
MSA overview web page with links to the following PDF documents: Title:
The MSA in Bands 1G, 2G, and 3G. Description of Frequency Bands Title:
Three-Bead-Balun Reflection Bridge, 250 KHz to 1.5 GHz, 9/22/08 Title:
A Baluns and Beads Reflection Bridge, 50 KHz to 1.5 GHz, 10/21/08 Title:
The Active Bridge, 11/20/09 Title:
Manual Return Loss Measurements, 10/5/08. A manual analysis of Return
The Buffer Op Amp, 12/6/09. Dual buffer amp for use to 150 MHz. Title:
Using Test Fixtures for Measurement with the MSA, 12/4/09. Various
test fixtures and procedures for MSA, with test results. Title:
Test Results of Component Measurement with the MSA, 10/24/09 Title:
A Series Test Fixture for Measuring Impedance with the MSA, 10/5/09.
Test results using OSL calibration in component measurements with the
Series fixture. Title:
Antenna Testing with the MSA, 10/17/09 Title:
Determining Characteristic Impedance of Transmission Lines with the
MSA, 11/26/09 Title:
Analyzing Open and Short Coax Stubs with the MSA, 11/26/09 Title:
Measuring Transmission Line Loss with S21, 11/26/09. In Transmission
Analysis of Components with the MSA, 11/6/09 Title:
Filter Analysis. The Filter Analysis Function Title:
Changing the Graph Appearance in the MSA Title:
OSL Calibration Standards for the MSA. Nature and construction of OSL
The Basis of OSL Calibration of the MSA. Mathematics of OSL calibration Title:
Illustration of Plane Extension for the MSA, 10/21/09. Use of Plane
Introduction to the Smith Chart for the MSA, 10/12/09 Title:
S-Parameters and Related Quantities, 10/20/09. Introduction to
More Transmission Line Math Than You Want, 11/26/09. Details of
transmission line math. Title:
a Walk Through the MSA Software Spectrum Analyzer Mode, 12/12/09 Title:
a Walk Through the MSA Software Vector Network Analyzer Transmission
Mode, 12/12/09 Title:
a Walk Through the MSA Software Vector Network Analyzer Reflection
Mode, 12/12/09 Title:
Spectrum Analyzer Operating Guide for the MSA, 12/12/09. Bench-top
guide to SA operation. Title:
VNA Operating Guide for the MSA, 12/12/09. Bench-top guide to VNA
Builder's Group for those interested in
the MSA. There are many people in the process of building or
MSA and can offer suggestions and comments. This is a Yahoo Group
page and you are welcome to join and contribute.
name is Scotty Sprowls. I am a retired RF Design Engineer from
E-Systems / Raytheon. Although I am not an Amateur Radio
Operator, I repair radios as a hobby. My frustration in
tuning cavity filters in diplexers for a couple of Hams caused me
create this Spectrum Analyzer to aid me. You can get in touch
with me, via email,
I will try to
answer your questions or comments as soon as possible.
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