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ZL4AJS > QRP 23.06.05 15:40l 44 Lines 1451 Bytes #999 (0) @ WW
BID : 6E0169ZL4AJS
Read: GUEST DG9NBR
Subj: HF transformer cores
Path: DB0FHN<DB0MRW<DB0WUE<DK0WUE<DB0RES<ON0AR<ZL2BAU<ZL2WA<ZL4AA<ZL4GQ
Sent: 050623/0456Z @:ZL4GQ.#95.NZL.OC #:28816 [Invercargill] FBB7.00i
From: ZL4AJS@ZL4GQ.#95.NZL.OC
To : QRP@WW
Hi all,
I need a transformer for a PA design that I have built. It is for driving
the base of the final transistor and has a ratio of 4:1. I have wound the
one in there at the moment on a F43 material toroid, and it sort of works
but is not designed for use above 1 MHz. I has a lot of loss at 3.5 MHz
and this steadily increases until the PA doesn't even work above 4 MHz. I
want it to work up to 14 MHz.
Trouble is, I don't seem to be able to find an suitable core! All the ones
in the electronics catalogues are only designed for RFI suppression and I
don't know their frequency range. The catalogues do give their material
types, but they are not on my table showing the frequency range and
permeability. And I don't think any consumer devices have any in them
either. The only place to find them would be in a transmitter.
Here are the types I can get:
Ferrite: L8
L15
Powdered Iron: HY-2
Maybe someone knows what these types are for or can find it on the
Internet for me.
I'm not sure but I don't think air-cored transformers work very well for
driving transistor bases do they?
Thanks for any advice...
73.
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:: Andrew ZL4AJS@ZL4GQ.#95.NZL.OC ::
:: High School student (homeschooled) 17 ::
:: Ohai, Southland, NZ ::
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Timed 16:51 on 23-Jun-2005
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