Electronics > Beginners
Boonton 102F on Ocilloscope
DannyKlenz:
CR 14 is reading .350 in the bad direction. I have a bunch of 4000 series diodes 01 04 07 etc... Going to check if I can drop one in
rf+tech:
Dan,
To see the modulation envelope, it is necessary to slow the sweep speed d-o-w-n to audio. Reread my previous reply. The actual RF cycles will be indistinguishable. To see two cycles of 1 kHz requires a sweep speed of 200 microseconds.
I see that the initial RF signal without modulation looks pretty good. What changed between the last video showing distortion? Disregard the distortion at high modulation depth. Focus on the fact that before turning up the AM control, the signal looks clean. What made the difference?
Thanks for posting the schematic. I see Boonton changed a few things here, between 102D and 102F. The above mentioned coupling capacitor at the Schottky detector diode has been removed. And the vernier control signal gets applied off-board to the AM input (bottom edge of the Output PCB schematic). Let's see, this may be located on the Output Level Meter PCB. We need to locate the page with the RF Output vernier control, to see where the control voltage gets summed into the AM input.
Hold on a moment, CR14 cannot be replaced with a 1N400x. The only suitable replacement for CR14 is another Schottky diode such as 1N5711. The forward drop of a Schottky diode is about 0.35 Volts. So your measurement is good, not sure what you mean by "bad direction".
RF+ Tech
DannyKlenz:
Sorry I got ahead of myself. Went and read the datasheet and realized my mistake. I'll see about locating the vernier adjustment.
rf+tech:
Umm, the vernier is right there on the front panel... ;D the control just above the N connector, marked OUTPUT.
Vernier, as in fine adjustment and as opposed to fixed 10 dB steps. ;)
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