[Lowfer] Al Loop Conductor?

[Bill Ashlock]

Good Show, Ed! Proves again that good measurements speak louder than words. 

> Date: Sun, 6 Nov 2011 17:25:02 -0800
> From: evp at pacbell.net
> To: lowfer at mailman.qth.net
> Subject: Re: [Lowfer] Al Loop Conductor?
> 
> I have made some measurements comparing losses of big inductors wound 
> with 0.125" diameter sold aluminum and 0.1" diameter solid copper.  I 
> measured Q over the maximum range of frequencies my Q meter could cover 
> with its internal capacitor.  I'd have to dig out the data and remember 
> exactly what I did but conclusion was that the difference in Q could be 
> predicted pretty accurately by the difference in resistivity and there 
> were no other bad effects.  I can't find the data now but the 
> measurement range was at least as low as 200 kHz.  Subject came up when 
> some of the Tesla coil 'experts' wrote that aluminum was useless at RF 
> because it was many times lossier than copper.  Not true!
> 
> Ed
> 
> Bill Ashlock wrote:
> 
> >Hi Scott,
> >
> >Considering the exchange of info on this topic I conclude we have the density and DC resistivity of Cu vs Al pretty well in hand but what about the Rac of Cu vs Al? Has anyone measured the Rac of aluminum conductors... and at different frequencies? Also we shouldn't forget the 'proximity effect' and the 'skin effect' when using large diameter conductors. I proved at 185K that the reduction in Rac was quite small when the conductor diameter was increased. Even separate insulated conductors twisted together netted little improvement over a single conductor and only when the spacing was approximately 1" was there a worth-wide improvement. Twisted, insulated, conductors do not define Litz cable. The interweaving needed is much more complex than this.
> >
> >Bill
> >
> >  
> >
> >>Date: Fri, 4 Nov 2011 21:07:43 -0700
> >>From: sthed475 at telus.net
> >>To: lowfer at mailman.qth.net
> >>Subject: Re: [Lowfer] Al Loop Conductor?
> >>
> >>Hi Warren
> >>
> >>My 100m perimeter LF loop is constructed of similar AL wire.  You'll 
> >>find it the PERFECT loop conductor as it's much lighter and cheaper than 
> >>copper.  The conductivity issue is not that big of a deal as my 
> >>conductor had much better conductivity than calculated.  I figure this 
> >>is due to the increased surface area based on the stranded nature of its 
> >>construction.
> >>
> >>Another nice feature of neutral supported cable type conductor is the 
> >>insulation is tough and will have been tested by UL/CSA or similar to 
> >>have a dielectric withstand in excess of 3KV.  No arcing here ever.
> >>
> >>Just ensure you use a suitable compound on any joints to mitigate oxidation.
> >>
> >>73 Scott
> >>VE7TIL
> >>
> >>
> >>On 11/4/2011 5:29 PM, K2ORS wrote:
> >>    
> >>
> >>>Hi,
> >>>     I am considering using Aluminum service drop wire (3/0 gauge) as a
> >>>conductor for an LF transmitting loop. I know that the conductivity is not
> >>>as good as copper but it weighs so much less that I can use a larger
> >>>diameter conductor.
> >>>Has anyone tried this? How would it hold up when flexed by the wind ? Other
> >>>thoughts?
> >>>
> >>>73 K2ORS
> >>>
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