Hi,

I need some toroidal cores(powdered iron or ferrite) for general HF
use. So i guess i will be looking for cores in 3-30~ MHz range. I have
access to Philips toroidal cores in where i live and i need your advice
to find the suitable one. Waiting for your answers...

Thanks...

tictac1 wrote:
Hi,

I need some toroidal cores(powdered iron or ferrite) for general HF
use. So i guess i will be looking for cores in 3-30~ MHz range. I have
access to Philips toroidal cores in where i live and i need your advice
to find the suitable one. Waiting for your answers...

Thanks...

Suitable for WHAT? You say you "need" them, but what exactly causes
that need? What are you trying to accomplish?

Cheers,
Tom

There is no such thing as a single core type suitable for "general" HF
use, because the required core material depends strongly on just what
the use is.

You can, however, satisfy a large number of requirements with a few core
types. Micrometals type 2 or 6 powdered iron cores are suitable for most
high-Q inductors. I consistently measure higher Q with type 6 cores, at
least when sparsely wound, but type 2 is convenient for higher
inductances due to its higher permeability. I didn't know Philips made
powdered iron cores -- if they do, you should check their web site and
Micrometals' to find an approximate equivalent. The choice of core
material for RF chokes and broadband transformers depends on how much
power and how much DC current is involved. For low power applications
where there isn't a substantial amount of DC current, Fair-rite type 43
ferrite material is a good choice for those applications. If you need
more impedance, for example at lower frequency or in higher impedance
circuits, one of the 70 series materials would be better. Again, look at
the respective web sites to find an approximate equivalent material from
another manufacturer.

The sizes of cores you'll need depends on the inductance (for high-Q
inductors) or impedance (for RF chokes or broadband transformers) range,
power handling capability, and DC flux level you need to deal with. For
low power, low flux applications, (F)T-37 and -50 are popular sizes.
These are 0.37 and 0.50 inch OD respectively.

Roy Lewallen, W7EL

tictac1 wrote:
Hi,

I need some toroidal cores(powdered iron or ferrite) for general HF
use. So i guess i will be looking for cores in 3-30~ MHz range. I have
access to Philips toroidal cores in where i live and i need your advice
to find the suitable one. Waiting for your answers...

Thanks...

Thanks for the answers.. I already didn't say that i needed one exact
type. They will be used in HF transceiver projects(ie. VFO's, mixers,
BPF's and everything). I think that a toroid like T-50-2 would be
useful for many applications like those. As i said above i only have
access to Philips cores and i can't find a catalog to choose from. I
did a search on the net but didn't come accross anything handy. So if
any of you have used Philips cores in your applications i would like to
know what types do you use and what equivalents are out there for known
brands such as Amidon, CWS etc.

Thanks...

The Philips cores that you are referring to were probably manufactured
by Ferroxcube (Philips has sold the company to Yaego). You can find
data and a handbook at http://www.ferroxcube.com/

If you want a useful ham program (free) for designing with Ferroxcube,
Amidon, Epcos and air cores download "mini-RC Calculator" from
http://www.dl5swb.de/html/software_f...teur_radio.htm

Fair-rite (ferrite manufacturer) has a distributor in your country -
Turkey and they can be contacted at http://www.aktif-neser.com/


Roger


tictac1 wrote:
Thanks for the answers.. I already didn't say that i needed one exact
type. They will be used in HF transceiver projects(ie. VFO's, mixers,
BPF's and everything). I think that a toroid like T-50-2 would be
useful for many applications like those. As i said above i only have
access to Philips cores and i can't find a catalog to choose from. I
did a search on the net but didn't come accross anything handy. So if
any of you have used Philips cores in your applications i would like to
know what types do you use and what equivalents are out there for known
brands such as Amidon, CWS etc.

Thanks...

I checked Fair-rite's site but couldn't find anything about frequency
characteristics of toroidal cores. Also, you know, as a homebrewer i
can't buy parcels of material like toroids, and I don't think that
distributor can sell small number of items, can they? Anyway, doesn't
anyone use Philips toroids, or is there no such thing as Philips cores?


Thanks...

Philips is no longer in the ferrite business!! They sold the company
to Yaego and it now operates as Ferroxcube. The Philips cores in your
area must be available as surplus parts. Use google "Philips
Components Magnetics" and you will find old spec sheets.

You can find current toroid data and a handbook at
http://www.ferroxcube.com/ They have kept some of the Philips part
numbers.

More toroid info at
http://www.electronics-tutorials.com/basics/toroids.htm and
http://users.catchnet.com.au/~rjandusimports/

Did you download "mini-RC Calculator" ???
http://www.dl5swb.de/html/software_f...teur_radio.htm

This program will answer many of your questions.

Roger






tictac1 wrote:
I checked Fair-rite's site but couldn't find anything about frequency
characteristics of toroidal cores. Also, you know, as a homebrewer i
can't buy parcels of material like toroids, and I don't think that
distributor can sell small number of items, can they? Anyway, doesn't
anyone use Philips toroids, or is there no such thing as Philips cores?


Thanks...

tictac1 wrote:
I checked Fair-rite's site but couldn't find anything about frequency
characteristics of toroidal cores.

???

On the main page, under "Technical Articles", "Use of Ferrites in
Broadband Transformers" has a large amount of information about
frequency characteristics. So does "How to Choose Ferrite Components for
EMI Suppression".

Also, you know, as a homebrewer i
can't buy parcels of material like toroids, and I don't think that
distributor can sell small number of items, can they? Anyway, doesn't
anyone use Philips toroids, or is there no such thing as Philips cores?

I'm puzzled. . . does Philips sell small numbers of cores directly
either? I'm sure some of the folks here can recommend retailers who sell
a small number of cores from various manufacturers. The last time I
checked -- some time ago -- Amidon was still selling Micrometals
powdered iron cores and ferrites from Fair-rite and Magnetics.

Roy Lewallen, W7EL

I'm puzzled. . . does Philips sell small numbers of cores directly
either? I'm sure some of the folks here can recommend retailers who sell
a small number of cores from various manufacturers. The last time I
checked -- some time ago -- Amidon was still selling Micrometals
powdered iron cores and ferrites from Fair-rite and Magnetics.
=================================
In the UK there are quite a number of small retailers which can supply
ferrite as well as powder iron cores.
www.sycom.co.uk
www.jabdog.com
www.modecomponents.co.uk

Also the G-QRP club sells both types of cores to members.


Frank GM0CSZ / KN6WH