Ed, Cortezsailor, Ziggy, et al,
1) First and foremost, there is a wealth of detailed (and even brief) info on this subject right here on Cruiser's Forum, and I'll add the links to these recent discussions below...
2) Secondly, here's the brief skinny!
a) If you can fit a 0.405" diameter coaxial cable from masthead, thru to where your VHF radio is (or will be), and can dal with running this size cable, then....use a good quality (name brand) RG-213 coax...such as Belden, DavisRF, Commscope, Times, etc....
Use quality connectors, and have them properly installed, and weather-proofed!!
Doing this, you'll be good for 20 years or more!! With no worries....
Originally Posted by Sailorman Ed
So for about a 75 foot run, LMR-240 (least cost), RG-213U, LMR-400 or LMR-400DB (highest cost) ? Looks like I will be pulling the mast so replacing the cable now makes sense AND I can relocate the VHF into the cockpit
. Does the center being stranded vs solid make a difference here?
b) If you cannot fit this 0.405" cable, then use Times LMR-240UF.....(or in a pinch, Belden RG-8x)....
Note that the LMR-240UF uses a stranded copper center conductor....and that any "LMR" cable that is not suffixed "UF", will have a solid center conductor (as the LMR-400 and LMR-400DB, have a solid, copper-clad, aluminum
c) If you wish to curse the day you decided to change your VHF cable, just try pulling LMR-400, thru your mast and bilges!!
In addition to it being stiff and not able to be "kinked" at all, it is not really a good cable for any "unsupported vertical runs"...
In actual fact LMR-400 is one of the worst choices for our VHF marine antenna
systems on our sailboats...
(LMR-400UF is fine....but it is still big and stiff...)
The difference is cable loss, RG-213 vs. RG-8x, vs. LMR-240uf....for a 75' length is actually pretty damn small!!
If you read the other threads I'm going to reference below, you'll see that the extra db to db and a quarter, you may pick up, will not be noticed in real use...(as long as you're not considering using RG-58!! Which is NOT acceptable for this application...)
75' of Belden RG-8x ~~ 3.4db
75' of LMR-240UF ~~ 2.25db
75' of Belden RG-213 ~~ 2.1db
But, what IS noticed is the difference between old, moisture laden coax, with corroded connectors, etc. and a new cable, with new clean connections!!!
VHF and AIS Radiowave Propagation and VHF and AIS Radio Range
Coax: - solid, untinned center conductor?
Pull VHF cable through mast
Top of mast, or RG213.... cant do both!
Connecting VHF, AIS, GPS - NMEA0183 and NMEA2000
AIS Antenna on Spreaders
I do hope this helps...