Quote:
Originally Posted by dtvmcdonald
The easiest and best way to measure the self-resonant frequency of a coil
is with a grid-dip meter and freqency counter or SDR receiver to get frequency accuracy.
That's if they are unshielded. If shielded, feed from a signal generator
through a 270K resistor and measure with a very low capacitance scope probe:
hook a 0.5 or 1 pF cap inseries with a short piece of coax. IF picky you can of course calculate the unloaded frequency.
I used both methods on my commercial ones for my CT-100 and they agreed.
I suspect you will be appalled with the frequency response of the Q channel.
|
Yes I have my Measurements Lab Grid Dip meter and plan to use to test it in that manner. However I have had consistent and pretty accurate results resonating the coil with my signal generator and frequency counter.
What is appalling about the Q Channel response? It is suppose to cut off at 500kHz. I was hoping to perhaps tailor it once I do the sweep.
I have been testing the circuits. I have audio and I can see some composite video. The Horizontal oscillator is properly locked but I have concerns about the vertical lock. I first need to do a complete IF alignment as I expect the IF response to be pretty horrible having had to reconstruct the strip.
I next need to fashion a jig to inject the frequency sweep to the mixer input.