[TowerTalk] Radial Connection to tower

[Stan Stockton]

Rick,

OK.  Just read this.  What would your best suggestion be for me to most effectively fix what I have described?

Stan, K5GO

Sent from Stan's IPhone



> On Dec 13, 2015, at 1:33 PM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
> 
> 
> 
>> On 12/13/2015 11:12 AM, Jim Lux wrote:
>> 
>> Putting strap, ribbon, or multiple parallel wires (that are close to
>> each other) reduces the R but doesn't change the L very much. The
>> magnetic fields couple between parallel wires or "filaments" within a
>> wide flat strip, so the L stays pretty much the same.
>> 
>> Strip has lower AC resistance (more surface area) than a round wire of
>> the same cross section.
>> 
>> So if you had multiple wires going out to the ring in different places,
>> you'll reduce both L and R (the magnetic field from the wires won't
>> interact).
> 
> It's worse that that.  The "proximity effect" is such that adding
> multiple wires in parallel isn't effective for either resistance or
> inductance.   Strip only has lower AC resistance when used as
> a transmission line like microstrip or stripline.  A strip in near
> free space (nowhere near a ground plane) suffers from current
> crowding at the edges; most of the copper goes to waste.  A round
> wire is unique in that is has no edges, so the RF current is
> forced to be uniformly distributed.
> 
> In my consulting practice dealing with RF plasma, I constantly
> run into clients with strips (they call them straps, whatever)
> flying around their machine as if they are accomplishing
> something more than round wire.  After cleaning up the rats
> nest, the clients are always surprised to find that stuff
> works a lot better.
> 
> If you want to read about this topic, study inductor design
> articles in the Radiotron Designer's Handbook (I think its
> free on line now).
> 
> Rick N6RK
> _______________________________________________
> 
> 
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk