Hi Mikek, In the figure, Zo is output impedance of the oscillator,
normally 50 ohms. The Zo resistor is the impedance match for the
oscillator. The "Injection Transformer" supplies 1/50 of the voltage
from the oscillator.
I'd try a FT50-43 for the core. An example in:
John KN5L
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On 9/16/22 5:57 PM, Mikek wrote:
John, now that I have thought about your graph a little bit, it seems
clear the primary needs more inductance.
To be flat down to 200kHz, I 'think' it would need about 160uh.
That would be 168 turns on that core.
?Was the point of your graph to show that the transformer needs more
work? Maybe a different core, maybe ferrite instead of iron?
Does anyone have a picture of the HP 4342A transformer?
?I added a schematic picture of the section about the HP 4342A
transformer. 50 to 1, has a 1 turn, 0.1¦¸ secondary output impedance, and
is flat from 10kHz to 70 MHz.
?My understanding is a 50 to 1 turns ratio is a 2500 to 1 impedance
ratio, so 0.1 x 2500 = 250¦¸ input impedance. Is this at 10kHz???
The resistor across the primary is 75 ohms.? Yes, I'm confused by it all.
????????????????????????????????????????????????? Mikek
