RadioBanter - View Single Post - Trying to find out what Ferrite material this is.

Owen Duffy · June 2nd 07, 11:18 PM posted to rec.radio.amateur.antenna

wrote in news:1180792808.218763.251660
@n15g2000prd.googlegroups.com:

Hello Owen,
I have tracked the product down to Jaycar but they don't know anything
about the material. The person I contacted was very vague and couldn't
steer me towards anybody that would know what material it was. All I
want to know is if the toroids would be any good for HF 1:1 baluns. I

You didn't ask that question initially.

As I said, I think that the material is low loss below about 1MHz. I am
away from home at the moment and don't have access to my records of
testing the things.

I doubt that the material is suitable for a HF voltage balun. Lossy
ferrite is still usefull for suppression purposes, and you could probably
use the cores for a 1:1 choke style balun at HF. One of the issues with
lossy choke baluns is efficiency of the solution, and more importantly
power rating.

Jaycar also sell powdered iron cores in similar sizes (LO1246, HY-2
material, ui 75, Al 165nH). They have much lower ui (need more turns for
a given inductance), lower loss, and are more expensive.

have just made a balun using a FT-140-61 which is very close to the
same dimensions as the 2 toroids in the Duratech packet. If they can
be used they are a fair bit cheaper than sourcing FT-140-61 toroids.

For some reason, US magnetics are overpriced in Oz. It seems everyone
charges FedEx rates to post a couple of dollars worth of cores that
should fit in a padded bag for $5. There is a market there for someone in
the US to sell reasonably priced Fair-rite or similar cores on Ebay with
low postage.

The other option is to try Neosid in Sydney, have a look at their web
site. I know they do a range of ferrites and powdered iron cores of
various shapes and sizes.

In reply to Richard Clark, yes I do have a SWR meter.

If a given balun causes a poor SWR reading on a known dummy load, then
the balun is inadequate, but the converse does not necessarily apply. The
test is an important one, but not comrehensive.

Owen