That may not find all potential problems with the installation.
In particular, unless there is a strong over-the-air signal on channel 3 or 4 (depending on which you are using to test), the picture could look fine even if your installation has an ingress (the cable allowing external signal to leak into it) problem.
Ingress problems usually show up on cable channels 17, 18, and 19 as an intermittent herringbone pattern because the frquencies used correspond with those used over-the-air for pagers, and the pager signals are quite strong.
I wonder if you could use a radio scanner to test your installation for ingress: Connect it to one of the drops with a BNC-to-F adapator and then terminate the other end of the drop with a 75-ohm terminator. Then see if it picks up anything on the paging frequencies used in your area.
This would depend on how well-shielded the scanner itself is, however. That can be tested by terminating it's antenna input with a terminator and seeing whether it picks up any paging signals.
