Archive for tag: rf probe

More Meter Madness

January 12, 2009 | Amateur Radio | By: Mark VandeWettering

Okay, after having read WB8ICN’s postings on QRPedia, I decided to try to measure the impedence of both of my meters. I dug a 1.5M ohm resistor out of the pile, and hooked some jumper leads to it. I then did the following: Measure the resistance of the resistor, using the DVM as an ohm […]

The Tale of Two Meters

January 12, 2009 | Amateur Radio | By: Mark VandeWettering

Well, I’ve been mucking around with my RF probe circuitry a bit tonight, and encountered something pretty strange. I have two digital multimeters lying around, and my newly rebuilt RF probe/dummy load that I described earlier. I hook one multimeter to it, and I get a reading of 14 volts. I get my other cheapie […]

Diodes for RF Probes

January 11, 2009 | Amateur Radio | By: Mark VandeWettering

My dummy load experiment still has a few unanswered questions, but I found that the ARRL Handbook has had a circuit which is basically what I built, minus the one series resistor. It looks like this: Okay, they use a germanium diode with considerably lower voltage drop, and include a 4.7M ohm resistor in series […]