And so it begins...

[green]

I have a Rigol DS1052. Zapped a probe with it on x1 when measuring fly back, probably around 450V. Don't forget to switch probe to x10.

[Qiaozhi]

Question:
I am looking through the build manual and see on step 4, that you measure the flyback voltage across the damping resistor which should be in the neighborhood of 350 V. My scope has a input limit of 300 V, will this be safe to measure with a 10X probe? If not, what do you suggest I do to measure this.

Jamie

My scope also has an maximum input voltage of 300V, but I've never had a problem measuring the flyback voltage, even when much higher than 350V. Make sure you use a 10x probe. Even though I have sometimes (accidentally) had it on the 1x setting, nothing went up in smoke. There's most likely some protection diodes to take care of any excessive voltage.

[mushaba]

Question:
I am looking through the build manual and see on step 4, that you measure the flyback voltage across the damping resistor which should be in the neighborhood of 350 V. My scope has a input limit of 300 V, will this be safe to measure with a 10X probe? If not, what do you suggest I do to measure this.

Jamie[/QUOTE]
Hello Jamie and welcome to the forum.Make sure to switch from 1x to 10x on the probe and then via menu set the channel probe settings according to 10x.

[moorejl57]

Hi All, my first post, been lurking for a week waiting for my MPP kit to arrive!

After contacting Sven about his Mirage project, he pointed me to this site, the diy detector site and suggested I start with the MPP Beach. I just received the board and parts kit, a Whites space saver rod kit (very nice for the price), fiber bolt, 100' 24 AWG enamel wire, thin copper EMI tape and a Proster LCR meter (works pretty well).

I built my first ever coil by 3D printing a 170mm wide 8mm octagon with a hollow cavity for the wire and a slit on the outer perimeter to feed the wire in. I used the coil calculator to target 325 uH using 26 turns. The LCR meter reads it at ~328 uH, resistance right at 2 ohms, resonance at ~864 kHz with copper shielding in place and no lead wire. I am very happy with this first attempt even if the coil is a bit on the slow side. The 3D printed "donut" holds the coil together and provides a spacer between the coil and the copper shield. I think the dielectric constant of PLA is about 3.5. The calculated capacitance is about 103 pf.

Question:
I am looking through the build manual and see on step 4, that you measure the flyback voltage across the damping resistor which should be in the neighborhood of 350 V. My scope has a input limit of 300 V, will this be safe to measure with a 10X probe? If not, what do you suggest I do to measure this.

Jamie