"ml" wrote in message
...
hi

I've seen recently that some companies such as andrews etc are now
offering different coax and hardline with al outer shielding

they advertise lower cost, and lighter weight then copper , ok i get
that

but then they say the rf spec's are 'the same' so i ponder how do they
do that i would think copper would have better spec's ? obviously i
am missing something obvious

I think you are referring to the Times Microwave LMR cables. The LMR240 is
sort of a low loss RG8X, and the LMR400 is a low loss RG213. These cables
are made like RG6 in that there is 100% foil coverage bonded to the inner
dielectric with normally a tinned copper braid over it. The aluminum
versions of these replace the copper braid with aluminum braid. They claim
the loss is the same because the bonded foil is the same. The only problem I
see is soldering to the aluminum braid, and I suspect crimp on connectors
will be easier to install. You can still solder the center conductor. Check
out
www.timesmicrowave.com
BTW, the LMR240UF makes for great patch cords. It has a stranded center
conductor. 1/4 inch cable that is rated at 1500W. The LMR240 without the UF
suffix has a solid center conductor, costs about half as much, and I use it
for longer runs below 30 MHz. Haven't seen any of the aluminum stuff yet.

Tam/WB2TT