Do you know how far the JDSU SMART HOME V3 meter can test opens copper pairs
Good question and one I can't give a definitive answer to, I'm afraid.
The reason being that I've never had to test the TDR function of the JDSU to its upper limits .... there may well be some spec/doc giving that kind of information ??
The one thing I can say is that the further up the TDR spectrum you go (ie: the longer the length you are viewing), the trace becomes far, far more erratic and harder to 'read'. Simple poundage changes can appear as 'Full on disconnections', unless the operator turns the automatic gain function down.
On my JDSU (not certain what version it is, tbh ??) .... the TDR screen has viewing ranges from 'X-Short' (at zero metres +), through 'short', medium, long to the final viewing screen of 'extend'. The highest figure the TDR cursor can move to at that range is 13,320mtrs ...... so I suppose
that is the answer to the question in theoretical terms, but I much prefer practical experience when giving a reply.