Hi Brett, The following loss figures might influence what you do. Figures are from Wireman's published reference book but can be found in numerous sources.
Coax dielectric Loss for 100' @ 150 MHz Notes RG58U solid pe 5.1 dB solid center conductor RG58AU solid pe 6.8 dB stranded center conductor, 19 strands RG400 solid teflon 4.8 dB teflon jacket, center cond stranded silvered copper, double silvered copper shield, spec'd in aircraft cabling RG58 type pe foam 4.9 dB "CQ" brand sold by Wireman, typical value for store brand foam RG8X type pe foam 3.5 dB " RG8 type pe foam 1.5 dB " LMR500 pe foam 1.2 dB High grade .5 OD 50 ohm coax. If one is forced to use RG58/59 sized cable for various considerations, and particularly if exposed to weather, as in tie-wrapped to brakelines and such for a mobile installation, the 1.50 per foot RG400 is superior, used in aircraft cable assemblies for VHF/UHF and is flexible enough to go around bends without deforming the dielectric. It is also flame-proof, and cannot be overheated to melting while soldering or melted by proximity to hot engine/exhaust components. It uses RG59 adapter (UG176) for PL259. Since all the conductors are silver plated, minor water ingress does not ruin the cable as silver oxide is highly conductive vs. copper oxide which turns the shield into a green series resistor. Unlike some of the older high grade cable, RG400 is still being made new and can be bought by the foot on eBay. 73, Guy. On Sun, Mar 21, 2010 at 9:30 AM, Geoffrey Mackenzie-Kennedy <gm4...@btinternet.com> wrote: > Hi Brett, > > Certainly there are differences between RG58U and RG58A/U, but if the three > 50ft lengths you have are quite old I would suggest that the best way to > decide which piece(s) to use would be to measure the insertion loss of each > 50ft length at the frequency to be used, using a 50 +j0 load. > > 73, > Geoff > GM4ESD > > > Brett Howard wrote on Sunday, March 21, 2010 at 6:23 AM: > > <snip> > >> Anyway is there any reason not to use the RG58A/U or a compelling reason >> to use the RG58U over the RG58A/U? I know I really should use something >> other than RG58 if I'm going to be going any farther than the length of >> run that would be needed for a mobile. However at the moment the >> repeaters that I'm looking to be able to get into with this antenna I >> can hit with 5 watts (and the antenna in the same room with me). Its a >> just shy of 10 foot tall antenna in a room with 8 foot ceilings so its >> not exactly "vertically polarized" either... ;) > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
