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Old 10th Mar 2018, 11:24 pm   #20
G0HZU_JMR
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Join Date: Sep 2010
Location: Cheltenham, Gloucestershire, UK.
Posts: 3,077
Default Re: Testing unknown transistors for max frequency response

Quote:
It would be good to have the HP 1GHz vector voltmeter ! I guess transistor manufacturers could afford these tools.
I've got one of these old VVMs here but I also have the modern equivalent in the form of a 4 port VNA. If anyone is interested I could measure a (Farnell sourced Fairchild) BC547B and export s2p data for various Vce and Ic operating points.

It might be fun to convert these S parameters to H parameters and try and predict where Ft is and where the 6dB/octave slope is? I could post up the s2p data files here so people can have a play at home using tools like RFSIM99 or QUCS?

There are also various (free) GNU Octave tools available online for manipulating or converting s parameter data. Maybe this is all a bit OTT but some people on here might not have access to a decent VNA but they might still want to play with the data? If I buy some popular Ge RF transistors I could do the same with these.
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Regards, Jeremy G0HZU
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