Saturday, February 20, 2010

14.058 Mhz FM IF TX - overtone at 28Mhz

Another test for the 144Mhz FM transmiter. This time I tested an oscillator/modulator with an CD4069 (6 inverter ports on one package)
Sounds promising....

The schematic:

I used the "modulator" from SM0VPO QRP FM TX that connects to the BB109 varicap (on the above shcmatic) with an 10nF cap in the middle:

The cristal was on the junk box, I bough 40 diferent crystals in last ham radio fair, so plenty of them to test. This one came from a scanner receiver I think, judging from the marks on it (73.675 RX). If I am not satisfied since it oscilates on 14.058 Mhz could be used for my S9 signal generator.

Beeing the output at the 10m band it should be easy to make an up converter and do some filtering. Unfortunatly the FM part starts a litle big higger in frequency, else the schematic could double as 10m and 2m FM :)

1 comment:

Anonymous said...

Very Interesting!
Thank You!