Comments requested please on the following proposal :
If you are testing new modems or routers, or comparison testing, follow these recommendations in order to avoid letting DLM muck up the results by overpowering the differences between the kit with changes that would have been applied by DLM anyway.
1. First wait 30 mins, then
2. Turn off your existing kit for at least 30 mins, then back on again,
3. Make any measurements on existing kit, then
4. Wait for 30 mins, then
5. Turn off existing kit and remove
6. Wait for 30 mins, then
7. Plug in new kit and switch on
8. Make any measurements on new kit, then
9. Wait for 30 mins, then
10. If appropriate, make second set of measurements
11. Turn off new kit and wait 30 mins
As a check on the reproducibility of the test, could finally plugin existing kit and measure again, or even repeat the entire procedure.
(a) Don't perform these tests near dusk.
(b) Don't perform these tests when the weather is changing.
(c) Document the characteristics of your line; check your line's health and if there is any chance of there being a fault, write it up.
(d) Do not perform tests while powered from a UPS (paranoid).
(e) Keep mains cables away from ethernet cables and RJ-11 cables.
(f) Always use the highest quality cables possible - best RJ-11 cables (and Cat 6 or higher ethernet ideally SSTP or SFTP, and document what RJ-11 cables you used)