Re: Kludging together a TDR or similar?


Richard Knoppow
 

Yes. The velocity of propagation depends on the dielectric constant of the center insulation and my memory says the impedance of the cable. There are extensive charts of cable and air line coax that give the velocity of propagation. Typically, it is about 75% of the speed of light in a vacuum. Some TDRs have built in calibration for common cable types.
I used TDRs quite a bit in the past mostly for matching lengths of video cables. They can be very useful instruments.
The TDR can also measure the velocity of propagation if the distance to a discontinuity is known. From that one can derive all sorts of other information about a cable including its impedance.

On 6/28/2018 11:04 AM, cheater cheater wrote:
Thanks. Does the propagation time depend on the coax type?
i don't have the parts to build the circuit right now - could I use the
mainframe's pulse generator?
On Thu, 28 Jun 2018, 19:50 stefan_trethan, <stefan_trethan@gmx.at> wrote:
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL

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