>
It sounds like you've discovered your probe is the problem.
The way to verify this is simply to connect one probe and then the
other probe separately to the same test point and gnd point, and with
the probes connected to the same scope channel. Assuming the pcb
being tested isn't otherwise grounded [run it off a battery], then
the signals in the 2 probes will look very different, if one of the
probe grounds has a fault.
> I always connect the ground probes - In any of my descriptions up to
> this point (as hard to decipher they appear to be for anyone but
> myself) I have done this ...
>
> "input to the TX XBee and the output of the RX XBee", I assume you
> were comparing signals on the 2 different modules at the same time."
>
> yep, exactly that ...
>
> "This will only work properly with the probe gnds connected to the
> individual boards, which will electrically connect the gnds of the 2
> boards together."
>
> That was my original point - It doesn't appear to do this ... I had
to
> physically connect them at the circuit - a bit of wire from one
> breadboard to the other for it to work... - After further fiddling
and
> swapping the probes from input A to B I think one of the probes is
at
> 'fault' (either that or I am)...
>
> I have put both probes on the same pin of the RX (receiving XBee)
and
> connected the gnds to the battery power '-ve' that is powering the
> same unit - I get the same signal on both scope probes (as
expected) -
> yet when I disconnect the ground on the 'fluke' brand probe both
> signals go whacky (independent of whatever Input it is in) - if I
> disconnect the 'phillips' brand probe both signals are still good
> (regardless of it now being an 'antenna')
>
> - I reckon however that further discussion is just going to get me
> confused or at least you a little unfairly fatigued until I read up
on
> my scope basics ... At first I thought it was the XBee's but its
> really my misuse or misunderstanding of scopes (or a potential fault
> in the probe, unlikely though)
>
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