Homebrew Spectrum Analyzer Project.




"A spectrum analyzer (SA) is only worth as much as its first local
oscillator!"

( From private communications with S53MV )




    
Introduction.

    
This page will be a source for information on a spectrum
analyzer homebrew project. While surfing on the internet, I have gotten quite frustrated
about the lack of useful data. ( For whatever reason ). I like to provide as complete an information package
for those who want to homebrew a simple Spectrum Analyzer by using one ot more
TV ( CATV ) tuners as a frontends.
    

    
At this point my analyzer will be based upon TV tuners as frontend. Starting point was

 the "Poor Man's Spectrum Analyzer design. Also the K2BLA's "An Inexpensive Spectrum
Analyzer for the Radio Amateur" will provide idea's. ( QST Nov 1985 ) At the bottom of the page are more references.

    
My main  problem is to find a suitable set of CATV tuners plus documentation and spec's. 

    
Finally learned the difference between a socalled 125 channel and a 181 channel tuner. No difference in frequency coverage!

    
The newer tuners as used for KU band downlink receivers have an IF ot 479.5 MHz and cover 1.4 - 2,2 GHz as the older tuners
have IF outputs in the 45 - 60 MHz region ( channel 3 - 4 ).

     
At this point the design will be a conventional one with scanning from a ramp generator and manual adjustment
of the center frequency. No provisions are planned for computer interfacing. I expect problems with
a non linear freq. scale though. 

    
As soon as results with the CATV tuner are observed, a decision will be made to proceed or go with a moreconventional SA design approach. I have gotten from more then one amateur the advice to forget about this
approach and build a frontend using regular available components ( such as Mini Circuits ) or 

 Wideband and Low Noise VCO . Time will tell....

    
Your contributions to this collection and constructive comments are welcomed.

    
This is a Amateur radio project.





      
Progress Report:

      
As the TV tuners show quite a variety of needed voltages to operate, we have started
with  a power supply with the following output voltages:
      

+12, -12, +5, +20 adjustable, and +30 V for the tuning voltage.

       I recieved an 
early version of a poor man's spectrum analyzer from WB2BQR as a test bed.












Information and analyzer links:






































































      
SOURCES:

      


    • High Performance Spectrum Analyzer, W6URH, Ham Radio Magazine 197706.

    • Microwave Spectrum Analyzer, N6TX, Ham Radio Magazine 197807.

    • An Inexpensive Spectrum Analyzer For the Radio Amateur, K2BLA, QST 198511.

    • A Simple Spectrum Analyzer, Albert Helfrick, K2BLA , RFdesign, 198801.

    • An IF and 80 dB log amp for spectrum analyzers, Peter Bertini, K1ZJH, Comm. Quarterly Fall 1996.


    • Build your own Spectrum Analyzer, WA2PZO and WA2DRO.

    • Poor Man's Spectrum Analyzer, WB5IPM, 73 Magazine 198208.

    • Build a 5 to 850 MHz Spectrum Analyzer. Fred Brown, W6HPH , Communications Quarterly Winter 1997,

    • Build a high-performance Spectrum Analyzer for a fraction of the cost, Radio Electronics 199108.

    • Build Spectrum Monitor, Radio Electronics, 198909.

    • A Spectrum Analyzer for the Radio Amateur, VHF Communications 3/87, 4/87, 2/89.

    • Low cost Spektrumanalysator, Dipl, Ing, Max Perner, DL7UMO, Funk Amateur, 9710 and 8711













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