[amsat-bb] re: New Device for Homebrewers

["William Leijenaar" <pe1rah@xxxxxxxxxxx>]

Hi AMSATs,

These devices of infinion are very interesting, but can also give lot of 
headache to homebrewers.
I have some of the BFP520, and 420. These also go very high in frequency, 
but I faced also often problems as homebrewer hihi. What many homebrewers 
don't know, and the problem is that they can not see (read measure) it, is 
that you can have oscillations on the higher SHF frequencies.
A simple wire is for the higher SHF frequencies like a open circuit, and C's 
often don't work on e.g 20GHz. To avoid this you must use loosy circuit 
cariers, and not solder in free air or in a cavity hihi.

Where you can use them for is of harmonic generators. They work great !!! 
Just 10MHz square on the base, and you will have harmonics into the higher 
GHz bands :-)

In combination with a DRO they also work great, I've seen designs on 
internet.

Then the NF of 0.74 on 2.4GHz, I would better suggest to use a (HEMT)FET as 
they have much lower NF for these frequencies, and with proper care FETs can 
also be soldered by homebrewers without damage by static electricity. The 
secret is only to keep all legs short-circuit, and only disconnect them from 
each other when it is soldered into the circuit.

Just some information to the homebrewers...
This is William PE1RAH now in San Jose city, Costa Rica :-)
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