No doubt you'll get a few answers...

This is a good URL to compare line loss on;

http://www.ocarc.ca/coax.htm

A 50 metre run on 1296 of LMR400 is about 7.8dB

A 50 metre run of LDF4-50 (1/2" heliax) is about 4.2dB

A 50 metre run of LDF5-50 (7/8" heliax) is about 2.3dB

You can work out the difference in your install by scaling things
proportionally. Dont forget to factor in additonal loss for any mismatch.

You then have to ask whether that few dB will make a difference in
whatever your mode of operation and interest is. When a RX signal is
borderline that dB or two can make a useful difference.

Dont forget to factor in the cost of connectors. You may also find both
the LMR400 and Andrew cable is too rigid.

I'd personally stick to LMR400 simply because I see that as a major step
up from (say) RG213 (16dB loss per above) using roughly the same cable
diameter. Some of my interest is in low signal 144MHz work but I tend to
reduce that problem by using a preamp at the antenna. About the only
downside for me using LMR400 is its rigidity and turn radius limitation.
I also tend to think in terms of a link budget. Thats easy to do with a
path prediction program. (There are some GPL ones out there)

Hope this helps

Cheers Bob VK2YQA

ml wrote:
i've read the specs on some healiax and lmr 400 but i can't say that i
always can interpert it fully and confused myself basically
interperting a real world practical answer