[Boatanchors] Coils and the winding thereof

[Carl]

I got spoiled at a young age Mike. Living in the NYC area Radio Row was a 
short subway ride for a 14 year old with paper route or birthday/Christmas 
money in his pocket. The overwhelming amount of "stuff" had to be seen to be 
believed.

Plug in coil forms have been around since the mid 20's and very available by 
1930 as National, Hammarlund, and others were promoting prewound and blank 
forms every month.

I should have expanded on the pill bottle a bit. If you stuff it into an old 
tube base, and paint it to appear old it does an excellent job at no cost.

The shape of a former has no effect at the frequencies you will be working 
at. RF doesnt like right angles at high frequencies, Im not sure where the 
line is drawn.

The various webs and weaves were long gone by the late 20's in store bought 
radios. They died when AC sets came along in high production in 1927 or so. 
There is a lot of info on them on the internet from crystal and battery 
radio recreaters.

Most of the real poor component and material ideas were gone by the time the 
36 ARRL HB came out. This was the beginning of the "Golden Age" of radio 
where developments were fast and furious. There were more models available 
per company than even GM had cars in recent years.

My own interests start primarily with the 1935 metal tubes. There werent 
many decent RF RX or TX choices before that ( The 1935 HRO is an exception) 
and battery tubes are totally useless IMO except as shelf queens. Same with 
the majority of the earliest AC sets. About the only one that gets somewhat 
regular use here is a Radiola 18 for Red Sox games.

Carl


----- Original Message ----- 
From: "Michael Tauson" <wh7hg.hi at gmail.com>
To: "arc5" <arc5 at mailman.qth.net>; "boatanchors" 
<boatanchors at mailman.qth.net>; "milsurplus" <milsurplus at mailman.qth.net>
Sent: Wednesday, July 01, 2009 12:56 AM
Subject: Re: [Boatanchors] Coils and the winding thereof


> On Tue, Jun 30, 2009 at 2:19 PM, Carl<km1h at jeremy.mv.com> wrote:
>> I dont think Id use that material for any transmitting due to dielectric
>> losses.
>
> Likely.  The idea came from a gentleman who'd gotten his ticket in the
> late 1920s and it was how he created coil forms when he couldn't find
> (or afford) the ones he wanted.  Newsprint wasn't the only type of
> paper he used but it was the cheapest.  One difference was that he
> used shellac more than varnish though I'm not sure it should make any
> difference.
>
>> The pill bottles from the pharamacy work well at RF without Q 
>> degradation.
>> They come in several size up to 2" diameter and are often free for the
>> asking. They should handle at least 10W as long as copper losses are
>> minimum.
>
> True but in the 30s most prescriptions came in small cardboard boxes,
> tins or envelopes for solid material and glass bottles for liquid,
> something that continued into at least the late 1950s.
>
> Some plastic coil forms were available as were phenolic and ceramic
> but they were store bought and not everyone could afford that.  In
> addition, I have no absolute verification of this but I think I
> remember seeing spider web, basket weave and/or diamond weave coils
> used in transmitters as well as receivers.
>
> Speaking of ceramics, I wonder if there would be any problem winding
> things like RF chokes (filament etc) on square rather than round forms
> as long as the inductance works out.
>
> I think part of the problem here is in thinking in today's terms
> rather than in those of a young and basically broke ham during the
> Depression like the gentleman I knew back in my small person days.
> (He was the Depression era ham and I was the student, just to
> eliminate any confusion.)  I'm using the same basic components and
> techniques as found in the 1936 ARRL Handbook plus some earlier text
> material and applying the lessons he taught ... some of which involved
> words even the Navy didn't know.  ;-)
>
> This is where having nice relatively modern test equipment fails.
> While I've added both a capacitance checker and means to check
> inductors to the want list, I have to keep in mind that the tolerances
> then were a lot looser than they are now and that sometimes losses
> were a fact of life.
>
> Best regards,
>
> Michael, WH7HG
> -- 
> http://www.nationalmssociety.org/chapters/NTH/index.aspx
> http://wh7hg.blogspot.com/
> http://kludges-other-blog.blogspot.com
> Hiki Nô!
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