Need ferrite rod
Yzordderrex
I need to get hold of some ferrite rod that is 3/4" or 1" in
diameter. Material must be #61 or similar high frequency capable. 1"
long would be good, but I can cut. There is a site called www.stormwise.com
which claims to have the material in 1", but I don't know anything
about them. I would expect they would have to get material from one
of hte larger houses that I am familiar with, but I can;t find any of
hte familiar houses that has material.
Has anybody deal with this company or can offer another source for the
larger dia rod?
Silver is up over 3% today:)
regards,
Bob
N9NEO
amdx
"Yzordderrex" <powersu...@netzero.net> wrote in message
news:50878f8f-2cd4-4bc0...@m38g2000yqd.googlegroups.com...
I have never heard of one that long in one piece.
I don't know what your project is, but it might be cheaper to use a
bundle of smaller rods or stack toroids to get the length you need.
Maybe even slip a small rod into the center of the toroids.
You can stack potcores too, maybe fill the potcores with a toroids.
Since it is a rod you have a large gap anyway, so what is a small gap here
and there.
Years ago a recieved a box of potcores that were broken
and unusable for their intended purpose, I stacked a dozen or two with one
turn through them and measured over 4000 ohms at 1Mhz.
Mike
Tim Wescott
Amidon?
Check to see if you can find a Fair-Rite dealer that has it?
Use a great big ferrite bead or stacked toroids, and pretend they're not
hollow?
Rich Grise
> "Yzordderrex" <powersu...@netzero.net> wrote in message
>>
>> Material must be #61 or similar high frequency capable. 1" long would be
>> good, but I can cut. There is a site called www.stormwise.com
>> which claims to have the material in 1", but I don't know anything about
>> them. I would expect they would have to get material from one of hte
>> larger houses that I am familiar with, but I can;t find any of hte
>> familiar houses that has material.
>>
>> Has anybody deal with this company or can offer another source for the
>> larger dia rod?
>>
>> Silver is up over 3% today:)
>>
> I have never heard of one that long in one piece. I don't know what your
> project is, but it might be cheaper to use a bundle of smaller rods or
> stack toroids to get the length you need.
> Maybe even slip a small rod into the center of the toroids.
> You can stack potcores too, maybe fill the potcores with a toroids. Since
> it is a rod you have a large gap anyway, so what is a small gap here and
> there.
> Years ago a recieved a box of potcores that were broken
> and unusable for their intended purpose, I stacked a dozen or two with one
> turn through them and measured over 4000 ohms at 1Mhz.
When I was in Okinawa in the USAF (ca. 1970) I had a buddy who was a ham.
He built a kilowatt grounded-grid amp using surplus components, except the
4-400A, which I stole for him out of "bench stock". (one of our jamming
transmitters had a series-modulated magnetron.) Anyway, in the surplus
stuff were a bunch of coils or transfomrers that had ferrite slugs about
1" diam. and about 1" long. For the filament choke, he glued 7 or 8 of
them together lengthwise. It seemed to work, at least at 7-ish MHz (20
meter band).
Oki had a surplus store practically on every corner, from used/abandoned
WWII stuff - a radio hacker's dream! :-)
Good Luck!
Rich
Tauno Voipio
>
> When I was in Okinawa in the USAF (ca. 1970) I had a buddy who was a ham.
> He built a kilowatt grounded-grid amp using surplus components, except the
> 4-400A, which I stole for him out of "bench stock". (one of our jamming
> transmitters had a series-modulated magnetron.) Anyway, in the surplus
> stuff were a bunch of coils or transfomrers that had ferrite slugs about
> 1" diam. and about 1" long. For the filament choke, he glued 7 or 8 of
> them together lengthwise. It seemed to work, at least at 7-ish MHz (20
> meter band).
20 meter band is 14.0 - 14.35 MHz
I used a bundle of AM radio ferrite loopsticks for
the filament chokes in two grounded-grid linear
amplifiers: one with a pair of 4-250A's and the
other with a pair of 3-500Z's. The latter was built
in 1972 and it is still usable.
--
Tauno Voipio, OH2UG (and MSEE)
tauno voipio (at) iki fi
Tim Wescott
Stack some toroids and ignore the fact they're hollow?
I think Amidon sells big ferrite rod to use as plate and/or cathode
chokes in linear amplifiers -- check. Surplus Sales of Nebraska (I think
it's www.surplussales.com) has a bunch of not-so-surplus parts for linear
amps; they may have choke cores, too.
Rich Grise
> Rich Grise wrote:
>>
>> When I was in Okinawa in the USAF (ca. 1970) I had a buddy who was a
>> ham. He built a kilowatt grounded-grid amp using surplus components,
>> except the 4-400A, which I stole for him out of "bench stock". (one of
>> our jamming transmitters had a series-modulated magnetron.) Anyway, in
>> the surplus stuff were a bunch of coils or transfomrers that had ferrite
>> slugs about 1" diam. and about 1" long. For the filament choke, he glued
>> 7 or 8 of them together lengthwise. It seemed to work, at least at 7-ish
>> MHz (20 meter band).
>
> 20 meter band is 14.0 - 14.35 MHz
emoticon>
> I used a bundle of AM radio ferrite loopsticks for the filament chokes
> in two grounded-grid linear amplifiers: one with a pair of 4-250A's and
> the other with a pair of 3-500Z's. The latter was built in 1972 and it
> is still usable.
Kewl!
Thanks,
Rich
Yzordderrex
> "Yzordderrex" <powersupply...@netzero.net> wrote in message
>
> - Show quoted text -
Thanks for replies everyone. It appears to me that the cores are
actually 1"dia by 1.12" long. He sells them without the plastic
covering - scroll down to the bottom of the page. I'm guessing that
he glues them end to end or spring loads them in the tube in order to
get the long lengths for antennas. I'm going to have to try one of
his big ones out for AM DX.
http://www.stormwise.com/page26.htm
I've been working directly with Fair-Rite and they can create the
larger diameter parts in 1" length as well. I'm guessing there is a
limit to the ceramic technology which limits the actual size of the
part. Maybe the stuff is compressed in a press???
I've ordered a few of the 1.12" parts to prototype my converter, and
I'll work with Fair-rite when I go into production.
thanks-again.
regards,
Bob
N9NEO
mi...@sushi.com
http://tinyurl.com/yfehf6u
Unless I'm missing something in your argument, there certainly are
long rods of ferrite. They show up all the time on ebay. The problem
is no specs.
John Fields
<powersu...@netzero.net> wrote:
.
.
.
>I've been working directly with Fair-Rite and they can create the
>larger diameter parts in 1" length as well. I'm guessing there is a
>limit to the ceramic technology which limits the actual size of the
>part.
---
I don't think so; the limits seem to be imposed by financial
considerations.
---
>Maybe the stuff is compressed in a press???
---
From:
http://www.fair-rite.com/newfair/faqfer.htm
<BEGIN QUOTE>
Ferrite is a class of ceramic material with useful electromagnetic
properties and an interesting history. Ferrite is rigid and brittle.
Like other ceramics, ferrite can chip and break if handled roughly.
Luckily it is not as fragile as porcelain and often such chips and
cracks will be merely cosmetic. Ferrite varies from silver gray to black
in color. The electromagnetic properties of ferrite materials can be
affected by operating conditions such as temperature, pressure, field
strength, frequency and time.
There are basically two varieties of ferrite: soft and hard. This is not
a tactile quality but rather a magnetic characteristic. 'Soft ferrite'
does not retain significant magnetization whereas 'hard ferrite'
magnetization is considered permanent. Fair-Rite ferrite materials are
of the 'soft' variety.
Ferrite has a cubic crystalline structure with the chemical formula
MO.Fe2O3 where Fe2O3 is iron oxide and MO refers to a combination of two
or more divalent metal (i.e: zinc, nickel, manganese and copper) oxides.
The addition of such metal oxides in various amounts allows the creation
of many different materials whose properties can be tailored for a
variety of uses.
Ferrite components are pressed from a powdered precursor and then
sintered (fired) in a kiln. The mechanical and electromagnetic
properties of the ferrite are heavily affected by the sintering process
which is time-temperature-atmosphere dependent.
Ferrite shrinks when sintered. Depending on the specific ferrite, this
shrinkage can range from 10% to 17% in each dimension. Thus the unfired
component's volume may be as much as 60% larger than the sintered value.
Maintaining correct dimensional tolerances as well as the prevention of
cracking and warpage related to this shrinkage are fundemental concerns
of the manufacturing process.
<END QUOTE>
JF