Daily GLOWBUGS
Digest: V1 #116
via AB4EL Web Digests @ SunSITE
Purpose: building and operating vacuum tube-based QRP rigs
Subject: glowbugs V1 #116
glowbugs Saturday, September 20 1997 Volume 01 : Number 116
Date: Fri, 19 Sep 1997 19:20:06 -0400
From: benb27@juno.com (Ben C Bradley)
Subject: Ferrite vs. powdered iron/Re: Quick toroid question
I saw this last week, and I have to ask - what's the difference
between ferrite and powdered iron?
I do know (I think) that 'powdered iron', embedded in some kind
of glue or plastic, is made so as to make magnetic material that is
non-conductive, and so doesn't have the eddy currents a solid piece
of regular iron would, thus having less loss. I always thought
ferrite was just a name for this, or perhaps a brand name. What
actually is ferrite, how is it different, and what is it made of?
At 01:38 PM 9/12/97 +1000, Murray Kelly wrote:
>
>
>km1h @ juno.com wrote:
>
{snip}
>> The toroid should
>> be spaced at least its own height above an aluminum chassis, double
that
>> for steel. Altho a toroid is fairly self shielding it will be affected
by
>> large amounts of metal in close proximity.
>
>This is generous even for solenoids, according to antenna tuner mfg-ers.
>
>Ferrite seems best for transformers (baluns etc) and powder for resonant
>coils?
>
>> One other thing, in a TX ATU it would not be advisable to use ferrite
>> material. Powdered iron with a mu of 10 ( 2 Mix) or a mu of 8 ( 6
Mix)
>> is preferred at HF.
>
Ben Bradley benb27@juno.com
Date: Fri, 19 Sep 1997 17:07:43 -0700 (MST)
From: Chris Trask <ctrask@primenet.com>
Subject: Re: Ferrite vs. powdered iron/Re: Quick toroid question
On Fri, 19 Sep 1997, Ben C Bradley wrote:
> I saw this last week, and I have to ask - what's the difference
> between ferrite and powdered iron?
> I do know (I think) that 'powdered iron', embedded in some kind
> of glue or plastic, is made so as to make magnetic material that is
> non-conductive, and so doesn't have the eddy currents a solid piece
> of regular iron would, thus having less loss. I always thought
> ferrite was just a name for this, or perhaps a brand name. What
> actually is ferrite, how is it different, and what is it made of?
>
I'm glad you asked that question.
Powdered iron is, just as the name implies and as you have said,
iron ground to a pewder form and held together with a binder of some sort.
Ferrite, on the other hand, is also a powder, but, as stated in
the Philips Soft Ferrites data book:
"Ferrites are dark grey or black ceramic materials. They are
very hard, brittle, and chemically inert. Most modern magnetically soft
ferrites have a cubic (spinel) structure.
"The general composition of such ferrites is MeFe O , where Me
2 4
represents one of several of the divalent transistion metals such as
Magnesium (Mn), Zinc (Zn), Nickle (Ni), Cobalt (Co), Copper (Cu), Iron
(Fe), or Magnesium (Mg)."
Regards,
Chris
,----------------------. Circuit Design for the
/ What's all this \ RF Impaired
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ ATG Design Services
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ Technical Editor,
. ( ) \ QRP Quarterly
'-| )__| :. \ QRP ARCI 9464
| | | | \ '.
c__; c__; '-..'>.__ Email: ctrask@primenet.com
Graphics by Loek Frederiks
Date: Fri, 19 Sep 1997 21:14:07 -0500 (CDT)
From: Bob Roehrig <broehrig@admin.aurora.edu>
Subject: [none]
Anyone have the specs on a tube type CK534AX ? These are by Raytheon.
E-mail broehrig@admin.aurora.edu 73 de Bob, K9EUI
CIS: Data / Telecom Aurora University, Aurora, IL
630-844-4898 Fax 630-844-5530
Date: Fri, 19 Sep 1997 21:18:58 -0700 (PDT)
From: John Kolb <jlkolb@cts.com>
Subject: Re: Ferrite vs. powdered iron/Re: Quick toroid question
On Fri, 19 Sep 1997, Ben C Bradley wrote:
> I saw this last week, and I have to ask - what's the difference
> between ferrite and powdered iron?
> I do know (I think) that 'powdered iron', embedded in some kind
> of glue or plastic, is made so as to make magnetic material that is
Ferrites are generally alloys of other materials, not iron. Manganese-
zinc or nickel-zinc. They generally have higher permeabilities (more
inductance) than powered iron but much less stable with temperature.
BTW, I have a number of excess T37-2 and T50-2 powered iron cores,
normally recommended for use at 2 - 10 MHz.
John Kolb KK6IL jlkolb@cts.com
Date: Sat, 20 Sep 1997 10:55:23 -0400 (EDT)
From: leeboo@ct.net (Leon Wiltsey)
Subject: cap "poof" much sadness
Hi Gang
While using my trusty hw16 last night I got a crash and then smoke,
as one of the filters went south. It is a 4 section 40 -50-80-80 at 350v
the main filter for the rec section. If anybody has a junker hw-16 and can
send me
the main filter cap,would certainly appreciate it. Will pay any
reasonable costs. This is my main station equipment, so am
out of business now.
THANK THE LORD FOR ALL YOU HAVE
68 yr old semidisabled senior
(stroke got my balance & hand to eye coordination)
ham agn as KF4RCL TECK+ (MUCH HAPPINESS)
BUILD MOST STATION EQUIP
SUB.BA & GB-- NO SOLID STATE
LEON B WILTSEY (Lee) tel. 941 471 3739
4600 Lake Haven BLVD.
Sebring, Fl. 33872 (SEBRING) WHERE THERE IS NO QRM FROM THE LOCALS
Date: Sat, 20 Sep 1997 09:27:56 -0500 (CDT)
From: Bob Roehrig <broehrig@admin.aurora.edu>
Subject: tube help again
Another tube, which I have many of but can't find the specs for is
a 6AM6 made by Mullard. Any help appreciated.
E-mail broehrig@admin.aurora.edu 73 de Bob, K9EUI
CIS: Data / Telecom Aurora University, Aurora, IL
630-844-4898 Fax 630-844-5530
Date: Sat, 20 Sep 1997 13:46:55 +0100
From: BOB DUCKWORTH <bob@atl.org>
Subject: test3
test3
Date: Sat, 20 Sep 1997 23:35:58 +0000
From: Sandy W5TVW <ebjr@worldnet.att.net>
Subject: FS: SX-71
My Hallicrafters SX-71 is on the block. Cosmetically around an "8".
Working good electrically. Oscillation problem licked, all original knobs,
etc. Sell for $125 plus shipping/packing. I have another goodie I
found I need the cash for!
73,
E. V. Sandy Blaize, W5TVW
"Boat Anchors collected, restored, repaired, traded and used!"
417 Ridgewood Drive
Metairie, LA., 70001
End of glowbugs V1 #116
***********************
Created by Steve Modena, AB4EL
Comments and suggestions to modena@SunSITE.unc.edu