Re: LF: Re: Can an air cored LPF inductor have as high a "Q" as a toroidal wound one?

[David Bowman <davidg0mrf@gmail.com>]

Hi Chris.

I had that problem too. - See:

http://www.g0mrf.com/decca.htm

Eventually I had to remove a T225-3 in the low pass and replace it with 2 stacked (superglued) T200-2.

That should work well at your power levels.

73

David  G0MRF

On Thu, Mar 8, 2018 at 1:15 PM, <jrusgrove@comcast.net> wrote:

Tested -3 material ... it has higher losses at LF.

Jay W1VD


----- Original Message ----- From: "Chris Wilson" <dead.fets@gmail.com>
To: <rsgb_lf_group@blacksheep.org>
Cc: <dead.fets@gmail.com>
Sent: Thursday, March 08, 2018 7:00 AM
Subject: LF: Can an air cored LPF inductor have as high a "Q" as a toroidal wound one?

Hello  expert LF'ers!

The  centre  toroid  of  my  three  toroid  LPF heats up on the longer
transmissions  like  WSPR15.  I  have  added  a  small fan as a crutch
(thanks  N1BUG!) but I guess that's a crutch for inadequate hardware. I
was  wondering  whether  instead of buying a larger toroid, which seem
only  to  be  available  from the US at high cost, I could wind an air
cored  coil  of  similar  inductance. But I am unsure whether it would
have the required "Q" factor. Your opinions please? Thanks,

Also  I  am  wondering,  looking  at the Micrometals site, whether the
current -2 material can be bettered by using -3 material?

http://www.w1vd.com/LPF.pdf

and info on frequency range of these cores is at: http://toroids.info/

 
--
Best regards,
Chris                          mailto:dead.fets@gmail.com