VHF MCmicro wideband operation possible

[Paul]

Forget the TX VCO fine tuning to make it lock on your frequency; This is how:
Checking with the solder side of the RF board, you will notice a capacitor connecting the hot end of the TX VCO inductor with the varactors common end. Try replacing this cap (or add in parallel) a 47pf smd cap. Thats all.
I got full 136 - 174 MHz coverage.

The same can be done also to the RX VCO. By placing a 1nf cap in parallel, your RX VCO will lock full band, BUT there are two major problems to overcome: The narrow filters to both LO injection and antenna.

It is fairly easy to "widen" the injection filter:
1. Remove the middle coil.
2. Remove all capacitors between the two remaining coils except the capacitors in parallel with the coils.
3. Using one of the removed white caps, connect the hot ends of the two coils.

I don't have a ready solution for the antenna filter yet but I'm working on it.

if you think that the radio is not as sensitive (.35uV) as most radios (.25uV) you can add a small preamp by removing a capacitor and adding a BFR91 and two resistors between the 2nd and 3rd antenna coils.
More info to be posted on request.

73 de Paul SV2US