I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, and with a little work you can even connect two of them for 4:1 nalance.
73, Charlie, K4OTV -----Original Message----- From: Carl [mailto:k...@jeremy.mv.com] Sent: Saturday, February 15, 2014 11:05 AM To: Charlie Cunningham; 'TopBand' Subject: Re: Topband: Palomar R-X Noise Bridge The lowest loss cable I have here is 75 Ohm 1" General Cable Fused Disc; its under a differnt name these days. Mostly air with poly discs and used for the 200' runs for 10M, 2M, and 222 MHz. For the 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive been using ferrite sleeve baluns since the mid 70's; I was introduced to them by the company I worked for who was building equipment for the joint CIA/DOD Tempest program. Carl KM1H ----- Original Message ----- From: "Charlie Cunningham" <charlie-cunning...@nc.rr.com> To: <j...@audiosystemsgroup.com>; "'TopBand'" <topband@contesting.com> Sent: Friday, February 14, 2014 10:00 PM Subject: Re: Topband: Palomar R-X Noise Bridge > All generally true, I expect, but I also believe that dielectric constant > and dielectric losses also figure in and the lowest loss lines would be > filled with air, dry nitrogen or evacuated. I expect those would likely be > the lowest loss AND highest velocity factor cases. > > 73, > Charlie, K4OTV > > -----Original Message----- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > Brown > Sent: Friday, February 14, 2014 9:42 PM > To: 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > On 2/14/2014 2:17 PM, Carl wrote: >> Isnt that what "lowest loss" means? At least that was my intention. > > I must not have written clearly enough. I was not questioning the low > loss, only that the high Vf was the way to get it. > > You DO get the low loss by going to larger coax, (like the 7/8-in hard > line), but it's the fact that it's LARGER and has lower RF resistance, > NOT the higher Vf. > > Think of it this way -- The higher Vf cable has less attenuation per ft > because the higher Vf allows the center conductor to be larger. > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > one with with a solid dielectric and Vf =.66. If those coaxes are the > same diameter and of comparable quality, the stub attenuation and Q will > be nearly the same. > > 73, Jim K9YC > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 > _________________ Topband Reflector Archives - http://www.contesting.com/_topband