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## [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals

 To: Discussion of Ten-Tec Equipment [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals Steve Hunt Discussion of Ten-Tec Equipment Thu, 26 Jan 2012 16:52:25 +0000 mailto:tentec@contesting.com>
 ```Here's some calculations to support that last comment: Solid dielectric coax Vf=0.66 and foam dielectric coax Vf=0.85, therefore relative dielectric constants must be 2.29 and 1.38 respectively. So, if we keep the coax outer diameter the same, the foam inner conductor must increase by SQRT(2.29/1.38)=1.288; that makes the RF resistance 0.776 times what it was. If we assume a loss of 1.8dB in a particular length of solid dielectric cable, that reduction in RF conductor resistance reduces the losses to 1.5dB - *exactly the quoted figure*. In other words the increased centre conductor diameter and the consequent reduced copper losses *exactly* account for the quoted difference in cable loss; *losses in the dielectric are not a significant factor*. 73, Steve G3TXQ On 26/01/2012 15:57, Steve Hunt wrote: > If you look at the technical data for a Belden solid dielectric RG58 > (say 8259) and compare it with a foam dielectric RG58 (say 7807) you'll > see that the centre conductors are significantly different diameter: > 0.035" vs 0.044" - they have to be to achieve the same 50 Ohm > characteristic impedance with different dielectric materials. > > The difference in loss is almost totally down to the smaller conductor > diameter, not to differences in dielectric loss. > > 73, > Steve G3TXQ > > > On 26/01/2012 13:43, Carl Moreschi wrote: >> Here is some data taken from the ARRL handbook on losses for various >> transmission lines at 14 mhz per 100 feet. >> >> >> RG-58 hard dielectric 1.8 DB >> RG-58 foam dielectric 1.5 DB These two have the same I squared R loss >> >> RG-8 hard dielectric 0.85 DB >> RG-8 foam dielectric 0.6 DB These two have the same I squared R loss >> >> Open wire line air dielectic TV type less then 0.1 DB >> >> As you can see from above, the dielectric has significant meaning to the >> loss. >> >> Carl Moreschi N4PY >> 121 Little Bell Dr. >> Hays, NC 28635 >> www.n4py.com >> >> > _______________________________________________ > TenTec mailing list > TenTec@contesting.com > http://lists.contesting.com/mailman/listinfo/tentec > > _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec ```
 Current Thread Re: [TenTec] Re. [Ten Tec] Grounds and power grid noise, (continued) Re: [TenTec] Re. [Ten Tec] Grounds, Richard Schmidt Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Stuart Rohre Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Jim Brown Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Carl Moreschi Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Jim Brown Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Carl Moreschi Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Carl Moreschi Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Steve Hunt [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Steve Hunt <= Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Rick - DJ0IP / NJ0IP Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Richards Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Jim Brown Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Steve Hunt Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Steve Hunt Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Phil Sussman Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Rick - DJ0IP / NJ0IP Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Jim Brown Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Steve Hunt Re: [TenTec] Re. [Ten Tec] Grounds and balanced fed verticals, Carl Moreschi