Prerequisite reading: The ARRL Spread Spectrum Sourcebook

Adapted from designs by Amateur Radio Research and Development Corporation (AMRAD).  "Practical Spread Spectrum: A Simple Clock Syncronization Scheme" by Andre Kesteloot, N4ICK.

The initial test design will hop sequentially, in 1 MHz steps, from 902 MHz up to 917 MHz (16 channels).  The local oscillator frequency is determined via the diode matrix.

15,625 Hz REF
PLL N Counter		LO Frequency (MHz)	TX/RX Frequency (MHz)	IF Frequency (MHz)

1048			1048.0			902.0			146.0
1049			1049.0			903.0			146.0
1050			1050.0			904.0			146.0
1051			1051.0			905.0			146.0
1052			1052.0			906.0			146.0
1053			1053.0			907.0			146.0
1054			1054.0			908.0			146.0
1055			1055.0			909.0			146.0
1056			1056.0			910.0			146.0
1057			1057.0			911.0			146.0
1058			1058.0			912.0			146.0
1059			1059.0			913.0			146.0
1060			1060.0			914.0			146.0
1061			1061.0			915.0			146.0
1062			1062.0			916.0			146.0
1063			1063.0			917.0			146.0

Schematics

• GBPPR 900 MHz FHSS Transverter - RF Section  (99k PNG)
• GBPPR 900 MHz FHSS Transverter - Diode Matrix Section  (143k PNG)

Notes

• AMRAD Spread Spectrum Projects
• TAPR Spread Spectrum Projects
• Spread Spectrum Scene Magazine
• US Patent Number 2,292,387 - Secret Communication System  (707k PDF)  Patent granted to actress Hedy Lamarr - then Hedy Markey.
• Picture of Hedy Lamarr  (16k JPEG)