Hi all,
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I am sorting through my capacious parts bin and came across hundreds of old IF transformers of the kind you see in the transistor radios of the 60s and 70s (see attached pictures). Anyway, they're all color coded to indicate their intended use. Online sources differed in their interpretation of what the colors meant, so I decided to measure them and find out. I have about a hundred of each color and there are about 7 different colors altogether in my collection.
The simplest approach seemed to be to create a fixture so the transformers could be swapped in and out of a socket and readings taken of each in turn. I freely admit I struggled with this part. It ain't pretty, but it's the best I can manage with my shaky hands and poor eyesight. I've hooked this up to my HP VNA, but then it occurred to me I would also need to create some cal standards for this fixture (does that make sense?) Anyway, if you take a look at the pictures you will see what I've at least *attempted* to do here! I know there are terrible strays and parasitics from this lash-up, but the IFs will be relatively low, so I figure I can get away with it.
My question is: given that I'm going to be performing an S21 forward transmission test sweeping from 300khz through 50Mhz, which type of calibration should I choose from the analyzer's calibration menu? Or can I get away with just a normalization? I've only ever done S11 measurements in the past and calibrated with short, open and load. But this is different.....
Suggestions, please.
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Jinxie