[DSP-10] It works ! VHF VCO, KK7P DSP

[dsp-10@mailman.qth.net]

Hi All,

Another DSP-10 complete working with the KK7P DSP 

It was a fun project and went together well, have only bench tested so
far. The receiver sensitivity is phenomenal can detect signals below
-140dBm measured using a HP8640B Sig Gen

A few peculiarities with my unit, the VHF VCO would not lock unless the
slug in L102 is removed from the can. The control voltage is 2.5V at 147
MHz and approx 0.5V at 144 MHz. PLL operation appears normal although the
control voltage is a volt or so low. I can raise the voltage pulling the
slug in slightly into the can but the slug hangs out of the can loose.

I needed to reverse pins 4 and 6 (DAC L,R) to get my unit to transmit.
There was no TX audio on DAC L

Operation appears normal with this change


GL 73,

Bob Johansen WB2SRF