Hi:
As an alternative to using a Step Recovery Diode to generate the harmonics it may be possible to use a modified A45 Module from a PRC-77 military radio. The A45 Module is called "One-megacycle spectrum generator" and uses a PNP 2N2273 transistor to generate the harmonics with a fairly simple circuit powered by +10 Volts. In the theory of operation TM 11-5820-667-35 pg 2-22.3 "The sinusoidal 1-mc oscillations are applied to spectrum generator Q2 (2N2273) through coupling capacitor C3 (10 uuF) . The spectrum generator is normally cut off by the reverse base bias applied through R4 (19k), and conducts only on the negative half cycles of the 1-mc signal. A positive pulse, rich in harmonics, is developed across transformer T2 and coupled to first mixer module A44.
This might be an excellent replacement for the impossible to get SRD.
73,
Brooke Clarke, N6GCE
