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## Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much

 To: "Tower and HF antenna construction topics." Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much "Roger (K8RI)" "Tower and HF antenna construction topics." Fri, 05 Feb 2010 01:05:44 -0500 mailto:towertalk@contesting.com>
 ``` Jim Brown wrote: > On Thu, 4 Feb 2010 10:38:19 -0800, Rick Karlquist wrote: > > >> This is *generally* true, if comparing all copper cables. >> But even in that case, the HF loss is not proportional to >> DC resistance when comparing different sizes of cable. >> And all bets are off when copper plating is involved. >> It is also worth noting that Al has something like 1.6 times >> the DC resistance of Cu but only 1.3 times the RF resistance. >> Finally, 75 ohm cable has considerably more DC resistance than >> 50 ohm cable with the same RF loss. >> > > Rick, > > My point is that virtually all transmission line losses at HF are I squared R > losses. That's why you want to install the largest coax you can afford. 73 Roger (K8RI) > What R is will depend on the materials, and how they are affected by > skin effect. The equations on the LMR website that attempt to define loss are > first approximations of reality. Like any equation, it is based on certain > assumptions, and errors develop when those assumptions aren't exactly true. > Like > copper coated AL, copper coated steel, and a shield that is a combination of > AL > and copper braid. > > > _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, (continued) Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Jim Brown Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Richard (Rick) Karlquist Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Jim Brown Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Jim Brown Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Jim Brown Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Roger (K8RI) <= Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, jimlux Re: [TowerTalk] Coax Loss -- RG-Numbers Don't Tell us Much, Roger (K8RI) Re: [TowerTalk] Using Stubs to Reject Harmonics, TexasRF