[TowerTalk] Re: Air Dux and similar air wound coils
L. B. Cebik
cebik@utkux.utcc.utk.edu
Sun, 24 Aug 1997 06:54:07 -0400 (EDT)
My thanks to all who replied to the question on the source of Air dux or
similar air wound coils. Here is a compendium of the answers--some are
repeats of others, but it is a way of saying thanks for the thoughfulness
of the reply.
-----
This isn't exactly what you asked, but you might consider making your
own coils for this application. Air Dux is fine for some
applications, but high circulating currents in a resonant circuit like
an antenna tuner can be pretty hard on them. Last month's QST had an
article on rolling your own (pun intended), and one advantage is you
can use larger diameter wire than anything available from Air Dux.
I've used the solid copper wire intended for power line grounds with
great success. It's available in 0.200" diameter and will handle full
legal power with ease, where the Air Dux is quite likely to melt the
polystyrene at that level.
The secret to getting a nice looking coil is to stretch the wire just
before winding in order to remove those annoying little bends and
kinks. Unwind the whole length and tie one end down to something
secure. Holding the other end, give it a slow but steady pull until
you feel it stretch just a bit. Almost magically, any kinks or bends
will be gone and you'll have a nice straight piece of wire. Works
like a charm.
73, Bill W7TI
-----------------------------------------------------
This is a real problem. Only source of coils I could find was B&W and
they wanted $50 for a $2 coil. Each order from them is custom made!
The plastic strips they use today to wind the coil about has a much
lower melting point than in the old days. You can't solder any taps to
the windings without unsticking the windings from the plastic strips.
I really think there is no alternative but to roll one's own.
Unfortunately few of us has a
supply of silver plated wire! I've just used #10 or #12 copper wire and
my Autek RF-1 analyzer to hit the desired inductance. Only alternative
to this is the flea market.
73 de Brian
Vance Net Inc
--------------------------------------------
I think Surplus Sales of Nebraska may be one source.
ttul de Rich K0XG
---------------------------------------------
Davilyn Corp (800 235 6222 FAX 818 787 4732 WWW.Davilyn.com/Electronics)
has B&W type 3064 (10" long, 3" diameter, 4 turns per inch) and type 3027
(10" long, 2" diameter, 8 turns per inch) with no part number but just
listed as "air coil inductor" on page 43 of their 96-97 catalog. Both types
are $10 per length and these are the only two types of coil stock in their
catalog. I got some of each a few months back along with one of their roller
inductors and was completely satisfied.
Regards,
Pete
KS4XG
-----------------------------------------------------------
Air Dux is a brand name.
Allied 1 800-433-5700 with stores in about 37 States
Allied Electronics Catalog page 1006
and also page 992 these various types...
Single Beldsol Solderable Magnet Wire
Heavy Armored Poly-Thermaleze High Temp. Magnet
Wire
Bus Bar Wire
and one called Magnet Wire by Dearborn Wire and Cable, on page 1006.
These are all solid copper with a Polyurethane glaze or film on the
outside, or dual polyester film in the case of the Poly-Thermaleze.
Various AWG sizes from 12 to 32.
Sizes vary by manufacturer.
Mentions winding operations and intricate windings
Ken Brown, N4SO
QTH nr Mobile, AL/ EM50tk
qrp-l #622
n4so@juno.com
-----------------------------------------------------
Surplus Salse of Nebraska had a largish selection at Dayton this year but
had signs everywhere saying "close out". They are certainly worth a phone
call -- they advertise in QST.
Also, some years ago there was an article in QST, I think, about how to roll
your own Miniductor stock. A clone, but it worked.
73.
------------------------------------------------------------
LB, Nebraska Surplus has been carrying it for quite a while, though a bit
pricey.
::Press Jones, N8UG
::The Wireman, Inc.
::Landrum, SC 29356
::use n8ug@juno.com or (864) 895-4195 for tech help
::orders only use 800-727-WIRE(9473) or cqwire@juno.com
---------------------------------------------------------------
Ack Radio in Atlanta has them LB. I have several I bought just to put
on the shelf. If you want, can check Mon and see if Tommy stills has
some.
-------------------------------------------------------------
LB...I understand that Surplus Sales of Nebraska owns most, if not
all of the world supply of AirDux and B&W coil stock. They bought
it up when those manufacturers stopped making it.
I find a piece here and there at swaps, and buy whatever is available
for bike mobile antenna loading coils, antenna tuners etc. No! I
don't have any for sale.
Happy hunting. I think there might be a good business opportunity
for someone though....
72....Jim
Jim Kortge, K8IQY (ex NU8N) | NorCal, QRP-L
----------------------------------------------------------------------
>Try Surplus Sales of Nebraska. They are expensive, but the stock is new.
The concensus seems to be a. pay a premium to Nebraska, b. roll your own
per the referenced QST article, or c. hope that Tommy Ack is still the
reasonable dealer he was when I lived in GA a quarter of a century ago.
Again my thanks to all who replied.
Incidentally, I have received several link coupled ATU interest notes that
made special reference to 80 and 160 meters. This has been added to the
special note section of my file, and my thanks to all to whom the volume
of replies prevents an individual response. If the "druthers" could be
combined, I'd say folks want a big Johnson Match Box (or a little one)
with two additions: a. switch positions for the WARC bands as well as for
the harminic bands, and b. 160 added. I won't add that they want it at
1950s prices.
-73-
LB, W4RNL
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