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Re: [TowerTalk] What am I missing....balun

To: towertalk <TowerTalk@contesting.com>
Subject: Re: [TowerTalk] What am I missing....balun
From: Richard Solomon <dickw1ksz@gmail.com>
Date: Fri, 17 Feb 2017 11:17:37 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Just a side note, but I wouldn't
be so quick to advertise that I sell
components to those who violate
Federal Law.

73, Dick, W1KSZ

On Fri, Feb 17, 2017 at 11:12 AM, Jim Thomson <jim.thom@telus.net> wrote:

> Date: Fri, 17 Feb 2017 07:41:09 -0700
> From: Chris <EZRhino@fastmovers.biz>
> To: "towertalk@contesting.com reflector" <TOWERTALK@contesting.com>
> Subject: Re: [TowerTalk] What am I missing....balun
>
> Is there any chance this is an April Fool's joke?
>
> Chris
>
>
> On Feb 17, 2017, at 6:40 AM, ve4xt@mymts.net wrote:
>
> > I've been trying to divine a defence for this box, but can't.
> >
> > If I read K9YC's choke cookbook correctly, there's no way this could
> achieve the level of broadband choking claimed. Moreover, not only is there
> no need to enclose such a device in so expensive an enclosure, it would
> compromise power handling. And if you did, how do you mount it at the only
> place it does any good?
> >
> > When it appears the best-performing choke in Jim's cookbook is nothing
> more than a frequency-specific number of turns of coax through, at most,
> $50 in ferrite cores, with no bulky enclosure, I just can't see why anyone
> would pay $900 for this.
> >
> > Also, if the photo is akin to an "exemplar" piece of furniture, and the
> box is built to custom specifications, then the quoted specifications are
> meaningless anyway.
> >
> > BTW, isn't the attenuation noted (called return loss) the only way any
> choke actually chokes?
> >
> > I think Array Solutions has some 'splainin to do!
> >
> > Then again, PT Barnum has never been proved wrong.
> >
> > 73, kelly, ve4xt
> >
>
> ####  jay at array solutions posted a note on the AMP  reflector on tower
> talk.   The unit is optimized for the 11m folks like I thought.   Hence
> the  26.980 mhz marker on the screen.  Kelly,  return loss is just another
> way of expressing SWR .
> The higher the return loss, the lower the swr.  You sweep the unit and
> note the return loss.  IE:  what is the swr with the unit terminated with a
> 50 ohm  dummy load.   You would expect it to be dead flat or close to it,
> on the freqs of interest.
> Same deal  with LP and  HP filters, or say an amplifier on bypass mode.
>  At the telco I worked at, we used return loss measurements  exclusively,
> and nothing was expressed in swr ratios.
>
> ###  That is  RG-393 coax..  Double silver plated braids and  silver
> plated stranded center conductor.  Teflon dielectric and  FEP-9  outer
> jacket.  That stuff runs aprx  $7.00  per foot these days.   For  20-6m,
> type 43 is typ used .   If you look at the K9YC cookbook, he states either
> 31 or 43  used on 20-6m.   The price tag of the unit was not what I was on
> about, but the stated  1.8 to 60 mhz freq range on their site.
>
> ##  The fancy test gear is what measures the actual choke Z and RS of the
> choke.  Knowing that, then you can calculate the attenuation in db of   any
> shield current.    I think  you are confusing shield current attenuation in
> db...with return loss attenuation, which is also in db.
>
> Jim   VE7RF
>
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