On Nov 28, 7:44*am, Lemon Tree wrote:
How difficult are transistor with an Ft of 5GHz to use? *There are
some really cheap ones around these days like the 2sc3356 for
example. *I'd like to some to make a regenerative receiver but I worry
that even after careful PCB layout I would still have problems.
Anyway I am starting a new website where I intend to present many
useful circuits. *It is located athttp://circuitprofile.scienceontheweb..net
At the moment there is only XOR circuit, but that XOR circuit should
be helpful for anyone making a huff and puff stabilized oscillator
circuit.

I hacked a short monopole antenna plus antenna preamp with an NEC
20GHz FET on 1.6mm thick FR4 material, and it worked pretty well. I
needed to have a very linear phase response (20MHz to 2GHz) and it
took some work to get the bypassing right; there was a source resistor
to develop the needed gate bias voltage, and getting it bypassed
correctly kept me busy for a while. One result of the project was
that I became much less afraid to try things like that, though. I
didn't have any stability problems. I used 0402 size parts, mostly
because they fit together better with the transistor than 0603, though
I really don't relish working with things as small as 0402.

I agree with Michael that you should avoid using transistors that have
much higher Ft's than you need, but maybe you're thinking of a 1GHz
regen receiver.

With regard to the parts that places like DigiKey and Mouser and other
authorized distributors stock: I seriously doubt that any homebrew
projects are going to have much effect on what they stock. It's the
parts that are bought for production, by the reel, or at least by
hundreds for some of the more exotic parts, that get their attention.
If you see them with a stock of 10,000 or more of something, you can
bet they didn't get them because they got some orders from random
homebrewers.

Cheers,
Tom