[Microwave] Building a noise source/head

[DEHAYS Dominique]

I think the easiest way to obtain ENR is to compare  preamps at different 
frequency's  with the prof source and to play aropund with the ENR setting 

of the PANFI to get the same noisefigure as with the prof source ?


Not quite..; Each noise source has its own behaviour regarding so called " 
gain error" ( please read and read again the UFB article by DJ9BV telling 
all onthis subject) , ie : at a certain distance from the object you want 
to measure , two differents noise sources will not indicate the same NF. 
This is particularly dramatic with 15 db ENR noise sources . You have 
first to minimise the gain error : Low ENR noise source ( or 15db + good 
attenuator) + circulator ahead of the preamp , preamp must be well matched 
at the output too , or a circulator at the ouput is necessary too....
Problem is a little bit easier when the input match of the preamp is not 
too bad . By taking some precautions , your method works , but you have to 
be very carrefull.
73's Dom