I'm probably going to get shot down in flames for this, but is it possible that the ferrite core is saturating?
On 04/02/2019 21:13, barry halterman wrote:
Hopefully some could shed some light here.
I intended to put in a power meter in my ubitx, so I installed a FT37-43 toroidal core at the rf output
Connector (ran the center coax conductor though the core) with 3 turns for the secondary winding. One end of the winding was grounded the other end to a diode to a capacitor and 47 ohm resistor, in parallel, to ground. Upon key down in CW mode I measured around 3.4 volts which was about 11 watts out into my dummy load....So far so good!
This is where it gets interesting! With my SA the harmonics on all bands went from marginal to very poor. I pulled the toroidal core off the coax and the harmonics went back to marginal, where I started from. Why would a toroidal core at the output cause such a degrading of the harmonics?
Even the second harmonic was there with the toroidal core, and not with the core removed.
Puzzling, very puzzling!
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