While LMR400 is significantly lower loss than say RG8x the limiting factor in VHF communications is still antenna height not power output. For example the range you could expect for a typical sailboat with an antenna height of 64’. d = 1.2246 ∗ √hf d = 1.2246 ∗ √64 d = 1.2246 ∗ 8 d = 9.796 NM. If the other boats mast is the same height you get a max range of 20 NM. That will not change if you use RG8x or LMR400.
That said if price and cable thickness do not matter it may be the better choice. On the other hand it is heavier and may be more prone to water tunneling because of the greater diameter. LMR400 is more significant at mobile frequencies because loss is much higher in UHF and microwave frequencies. Jerry Sent from my iPhone Sent from my iPhone > On Jan 15, 2017, at 6:24 PM, Tim Goodyear via CnC-List > <cnc-list@cnc-list.com> wrote: > > There are some differences in LMR400 that you need to look out for. Most > importantly, it comes in both 50 and 75 ohm impedance ratings. You need the > 50 ohm version. Secondly, regular LMR400 is pretty stiff, so if you need it > to turn somewhat sharp corners (at the masthead / mast base) then you could > opt for the "Ultraflex", which is a little thicker, but easier to handle. > The connectors you need are PL-259. I prefer the crimp on versions, but you > should ideally use a specific crimp due set, which may not be worth getting > for a couple of connections. > > Thanks, > > Tim > (Ex 35-3) > > > > > > On Sun, Jan 15, 2017 at 5:18 PM -0500, "Frederick G Street via CnC-List" > <cnc-list@cnc-list.com> wrote: > >> Pete — I did this last spring; and I’m one of the ones you’re “hearing” >> about LMR-400 cable. LMR-400 has tight specs, so you’re likely seeing >> different variations in connectors or manufacturers; but all the LMR-400 >> cable should be identical in performance, with the exception of the >> highly-flexible variant (UF) and direct-burial (DB — which you shouldn’t >> need for the boat — if you do, you have bigger issues to deal with…). >> >> You can purchase the cable raw and get the field-installable non-solder >> Times Microwave EZ-400-UM connectors. These are easy to install; not quite >> as simple as the Shakespeare Center-pin connectors that Dennis mentioned, >> but Shakespeare doesn’t make connectors for LMR-400. The other thing you >> can do (what I did in my case) is to make the hole in the mast large enough >> for the PL-259 connectors; then use a Cable Clam as strain relief and to >> provide weather protection to the large hole. This worked great; and I >> ordered the LMR-400 cable pre-terminated on Amazon by these guys, who build >> to MIL-SPEC: >> https://www.amazon.com/Digital-Antenna-Genuine-Transmission-Connector/dp/B005DUXWMU/ref=sr_1_25?ie=UTF8&qid=1484518381&sr=8-25&keywords=lmr-400. >> They can make whatever length you need. >> >> For VHF antennas, the Metz and GAM are popular; I went with a Digital >> Antenna 222-VW antenna: http://www.digitalantenna.com/prods/vhfantenna_3.html >> >> — Fred >> >> Fred Street -- Minneapolis >> S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( >> >>> On Jan 15, 2017, at 12:19 PM, kelly petew via CnC-List >>> <cnc-list@cnc-list.com> wrote: >>> >>> Belated HNY, Listers, >>> I am having the standing rigging [rod] on my '91 30-2 re-done [hopefully, >>> re-headed]. >>> >>> Now that the mast is down, I am looking to replacement of all the wiring >>> and running rigging. >>> Regarding the VHF cabling, I am "hearing" that "LMR-400" is superior to >>> other alternatives. >>> So, I checked Amazon and, of course, found "LMR-400", but there appear to >>> be several varieties to choose from. >>> Or, perhaps, it's simply different terminal fittings on the same cable. I >>> can't tell. >>> In any event, I would appreciate any feedback on which cabling to use. I >>> need about 44 ft. >>> >>> And also, any thoughts on installation "best practices". It would seem >>> I'll need to cut one end in order to get it up the mast. Does this make >>> sense? >>> I would prefer NOT to have to cut and re-solder, but that seems to be >>> unavoidable. >>> Also, should I replace the interior cabling -- from the mast to the radio >>> -- as well? >>> >>> And finally, any thoughts on the best antenna to use? >>> >>> Thanks!!!! >>> >>> Pete W. >>> Siren Song >>> C&C 30-2 >>> Deltaville, Va. >>> _______________________________________________ >>> >>> This list is supported by the generous donations of our members. If you >>> wish to make a contribution to offset our costs, please go to: >>> https://www.paypal.me/stumurray >>> >>> All Contributions are greatly appreciated! >> > _______________________________________________ > > This list is supported by the generous donations of our members. If you wish > to make a contribution to offset our costs, please go to: > https://www.paypal.me/stumurray > > All Contributions are greatly appreciated!
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