On Sat, Jan 12, 2019 at 10:48 AM, jim wrote:
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K...Generally an RF generator output is "calibrated" with a termination connected ...Generator output 100 mv P/P open circuit ..when terminated into 50 ohm ..output "split"? half absorbed by generator, half by termination thus actual reading 50 mV ...
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with 50 mV open circuit through 50 ohm generator + 1200 through test probe = 1250 ohm? ...then terminated into 50 ohm
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voltage drop across 1250 ohm in series with 50 ohm termination ...roughly 25:1 means 1/25 of the signal is dropped across load, 24/25 dropped across generator/test lead
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1/25 of 50 mV is about 2 mV? ...
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You would do better with a random piece of coax and a blocking capicitor from the signal generator ...No coax?? use a twisted wire pair ...maybe noisier, but lots less loss ..short (2 - 3 feet of wire/coax)
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Jim
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On Saturday, January 12, 2019, 8:17:13 AM PST, Dave Space <davesspacebar@...> wrote:
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Thanks for all the info.? Ok trying to see if I got this. It does look like loading.
1x probe is 1.2k
10x probe is 8.9 Mohms
I checked the probe directly outputting 50mv verified 50mv through a .01uF blocking cap @ 11.996MHZ
I put the generator into tp17 and measured at tp17 and I would say less than 5mv p-p was being read from what I could tell.
I wasn't understanding if there is a way to now match this better or not?
Thanks
Ah ok, sorry missed this message before I tested.? Ok let me see if have something else that will work with less loss... I might have a coax I can put into some alligator clips or wire leads or something.
