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Message-ID: <20020514235019.73703.qmail@web13306.mail.yahoo.com>
Date: Tue, 14 May 2002 16:50:19 -0700 (PDT)
From: "Michael Silvers" <silversmj@yahoo.com>
Subject: LF: RE: litz wire
To: rsgb_lf_group@blacksheep.org,  lowfer@mailman.qth.net
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Hi Bill & Group,

I believe why Litz wire has such a low AC resistance
is because each strand is insulated and when soldered
together you get the parallel resistance of each of
the strand of insulated wire.  With uninsulated,
stranded wire you may have the same current carrying
capacitiy but you more than likely have a higher
resistance because all the strands are in contact with
one another & the current path will be through all the
contacts that offer the least resistance but better
than solid wire because of the increase perimeter
length.

If you know the particulars of your type of Litz wire,
looking on http://www.mwswire.com/insspec.htm may
offer some help to what method will be required to
strip your type of wire.  For example, the polyimide
type insulation will be impossible to strip with a 
soldering iron, thermal class 2400C.  Methylene
chloride is your best bet.  The 1800C thermal class is
solderable but with large wire diameters may still be
difficult with a soldering iron.

73 de Mike KB6WFC

--- "Ashlock,William"
<William.Ashlock@edwards.boc.com> wrote:
> Mal and LF group,
>  
> Thanks for all the comments on how to strip the Litz
> wire. I'm continuing to
> experiment and last night I placed a sample of the
> wire in my paint stripper
> for an overnight test. This morning the color had
> changed from a red to a
> typical bare copper color, but a check of the
> conductivity indicated there
> is still some insulation remaining. It's back in the
> stripper at the moment
> for another dose. My conclusion is that this
> stripper is too weak to handle
> the job. Typical of most dangerous products on the
> market these days, it's
> probably been 'watered down'. 
>  
> Mal, I'll check the ingredients tonight and see if
> Methylene dichloride is
> one of them. Thanks for this. 
>  
> BTW, with all due respect, I don't buy your: "3mm
> litz wire is marginally
> better than normal 2.5mm stranded insulated wire the
> advantage is small", if
> you are talking TX loops (which may not have been
> the case).  My TX loop
> measurements indicate the Litz would be 2.4x lower
> in Rac, separate from the
> soil loss, which runs 0.22 ohms (dry) on my 50'/50'
> loops. I should have a
> complete table of many TX loop conductor
> configurations with Rac totals,
> including soil loss from <0.40 (4xlitz) to 1.4
> (single #12), completed in
> about a week.
>  
> Bill A
> 
>  
> Hello Bill and all
>  
> To remove the enamel from litz wire I use paint
> stripper called nitromorse. 
> Remove all the cotton/plastic insulation from the
> cable end to be soldered
> to expose the multi strand enameled wires. Brush the
> end of cable with a
> tooth brush to separate the strands and flatten out.
> Use the tooth brush to apply the paint stripper to
> the splayed out cable
> strands, making sure it gets to all the strands.
> Leave for about 10 minutes
> or more, then brush away the disolved enamel. I
> carry out this process twice
> to ensure that all enamel has been removed. The
> final job is to wash the
> exposed copper cable  end with turps etc using a
> cloth, then start
> soldering. I strip back about 1 inch of the cable
> end.
> I have used the above procedure a number of times
> and it works well. Paint
> stripper and a tooth brush are readily available.
> This method is also
> economical on solder, no need for special tools like
> solder pots and bunsen
> burners.
> Any good paint stripper would do. My contents label
> says the stripper
> contains 5 - 20 percent
> Methylene dichloride, it does not say what the rest
> is.
> This is dangerous stuff to get on skin, eyes etc and
> brush away from you so
> that it does not flick into your eyes or skin.
> The container/can specifies what precautions are
> nessary for use.
> I find although 3mm litz wire is marginally better
> than normal 2.5mm
> stranded insulated wire the advantage is small
> compared to the effort
> required to solder and weight considerations,
> especially for large loops or
> horizontal wire antennas. I also have noticed since
> winding my 0.5 mH
> loading coil for the vertical with 3 mm litz wire it
> is more critical to
> keep on the nose at resonance, possibly because of
> the higher Q than the
> previous 2.5 mm multi strand insulated copper wire.
> I hope these observations help you.
> My current 90 metre perimiter loop uses 2.5 mm
> insulated wire. I use it for
> RX only and as said previously I have to throttle
> the RF gain back on even
> the very weak signals. I do not use any preamps only
> the RX or Level meter
> SPM 12. I cannot see any advantage using litz for
> this purpose.
> To use the loop on TX there would be an advantage
> using litz but probably
> the db gain would hardly be noticeable. 
> Very small loops on LF like 1 metre square etc might
> be a different story,
> but this does not apply in my case.
>  
> 73 de Mal/G3KEV
>   
>  
>  
> 
>
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