Roy Smith wrote:

In article ,
Jim Burns wrote:
Does anybody know the typical range of the DME signal when DME is installed
in conjunction with a localizer or ILS?

Questions like this are best answered by reading the AIM, Chapter 1
(Navigation Aids). It's on line at http://www.faa.gov/ATpubs/AIM/.

A quick read of Section 1-1-7 says range is up to 199 nm, at altitudes
high enough to have line-of-sight to the ground station. There's
nothing in there that leads me to believe that a DME co-located with
an ILS is any different from one co-located with a VOR.

This is from AC-0031A (on Summit Aviation Reference Library CD). It is about
frequency protection for VOR, ILS and DMEs. Sort of technical but does show
they do a lot of tinkering depending upon circumstances:

b. Interference Protection of DME/TACAN. The following interference signal
protection ratios shall be provided within the operational service volume of all
DME/TACAN stations with a 95 percent time availability. This is done by
controlling the station separation in certain cases.
(1) The D/U signal ratio between co-channel DME/TACAN stations shall not be less
than +8 dB.
(2) The D/U signal ratio between adjacent channel DME/TACAN stations shall be as
follows. The various D/U ratios have been established recognizing the spectrum
control characteristics reflected in paragraph 124 and the spectrum differences
between DME and TACAN.
(a) When the undesired station is a TACAN, the D/U ratio shall not be less than
-42 dB.
(b) When the undesired station is an LDME (1000 W transmitter), the D/U ratio
shall not be less than -39 dB.
(c) When the undesired station is a TDME (100 W transmitter), the D/U ratio
shall not be less than -29 dB.
(3) The D/U ratio between DME/TACAN stations with more than 1 MHz separation
shall not be less than -50 dB.
(4) Some peak power deterioration is allowed before the system is shut down. In
order to account for this decrease in power, the actual D/U values used for
station separation calculations are 3 dB more protective, for example, +11 dB
vice +8 dB, -39 dB vice -42 dB, etc.
c. Protection of Service Volumes Which Extend Beyond National Borders. Stations
near the border are normally not frequency protected for that airspace which
lies beyond the national border. Standard service volume and expanded service
volume protection may be provided upon proper coordination with Canada or
Mexico. This must be done whenever specific airways, routes, or procedures
beyond the border are based on ground stations in the U.S.A.