Try to change transistors.2sc2571a or bfr96 bfr91 or any other with
ft of 5 ghz.
There is big chance that capacitor values in crystal filter are not
appropriate. Even behavior of the crystals in lattice filter on such
high if should be considered.
It is not that we missed your work in fact we looked at it with
great interest. I was interested in a PLL design for VFO for long.
My opinion by using a PIC we complicate things.
Now a PIC and 145170 combo is as simple / complex as PIC and
AD9851. Since we can get the DDS chips as free samples hence a DDS
design appears more practical.
This does not means that a PLL is no viable , I have been working
on a dicreet design using 74192 chips with 10Khz ref pulling. The
same comcept can be implemented upon a MC145151 as done in Multipig
design.
You are right about high ft IF limitations . As per simulations
done by our Prof Rob there appers roll off of frequency due to
highly negative feedback nature of amp designs. I am evaluvating
results of high Ft BJT devices. Maybe one back this design would
evolve into a basic building block towards a multibander.
73
Rahul VU3WJM
eb7hpm <msraya@t...> wrote:
I want to contribute the comunity with my work and that you not
missed the earlier post. I don't want recognition, I only want to
ear coments about the circuit from more experienced hams, I am
computer engineer!! ;-). I was looking for a good, simple and easy
design in the Internet but I not found it, It is the reason I make
the design and program to drive the PLL.
I don't know the designs of VK6BRO Richard Hosking, but i think
they
are complex. I will publish this work in the huff-puff group.
P.D: My BITX with a FI of 32MHz and VCO of 53MHz is working, but
it
is very bad, with BF495 transistor, i only output 1 Wat, and the
PLL
show some inestability. The VCO, BFO and filter works at 32MHz. I
think the bilateral amplifier don't work at 32MHz. I miss
something?
73s
Manuel
EB7HPM/EC7ALV
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