"Henry Kiefer" wrote in message
...

Ok Jim. You're asked about the stray components hidden in the real
parts/circuit.

There is nothing hidden at all. Strays are a part of the real life at VHF
and above. Sometimes strays have more effect than the part itself.



If you take the values from the datasheets for die and/or
package or give it a guess if not available, and add values for the pcb
lines, you have a good simulation result.

Horsefeathers. What "values" do you add for the pcb lines?



The pcb by itself is not of much
interest if you simulate not much over 100MegHz. Even starting a
oscillator
with thermal noise is possible!
Sure, you must know what you're doing :-)

As with anything in the world.



Spice by itself can simulate almost all if you have the right models
included - even if you wanna simulate a mechanical system. There is no
frequency limit at least to 100GHz.

The problem is getting the right models, which is an art in and of itself.




Do you had bad result doing Spice?

To come back to your question: Spice will give you better results than
your
real circuit! You can connect a probe with no interaction to the circuit!
Try this with your real parts! Don't forget the component variations in
real
circuits coming from the manufacturing processes of the parts.

Again I ask the question: What does Spice say about a 1000 pf capacitor
with 1" total lead length at 150 MHz.? Don't give me the BS about Spice
being "better than a real circuit". Until you can give me a ferrite slug on
one end of a toothpick and a brass slug on the other end to increase or
decrease inductance in Spice, the physical circuit is the "real" circuit.

Jim