Topband
[Top] [All Lists]

Re: Topband: Palomar R-X Noise Bridge

To: Charlie Cunningham <charlie-cunningham@nc.rr.com>, 'Carl' <km1h@jeremy.mv.com>, Top Band Contesting <topband@contesting.com>
Subject: Re: Topband: Palomar R-X Noise Bridge
From: James Rodenkirch <rodenkirch_llc@msn.com>
Date: Sat, 15 Feb 2014 09:45:11 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Carl:  I've read, at several places, that sleeve baluns are effective at VHF 
and above but not at HF frequencies..thoughts??
72/73, Jim Rodenkirch --- former Tempest inspector for the U.S. 
Navy..ahhhhh...Tempest comcerns - the good 'ol days  hi Hi!

> From: charlie-cunningham@nc.rr.com
> To: km1h@jeremy.mv.com; topband@contesting.com
> Date: Sat, 15 Feb 2014 11:39:14 -0500
> Subject: Re: Topband: Palomar R-X Noise Bridge
> 
> 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:km1h@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-cunningham@nc.rr.com>
> To: <jim@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-bounces@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
                                          
_________________
Topband Reflector Archives - http://www.contesting.com/_topband

<Prev in Thread] Current Thread [Next in Thread>