BTW, If you have an LCR meter I would definitely use it when winding the toroids. The published AL factors are an approximation at best. Getting the filter tuned correctly is hard enough without having to guess what the actual component values are. If you don't have a meter then you might be better off buying prewound inductors and adjusting your filter design to accomodate the available values.
Tony
________________________________
From:
[email protected] <
[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Tuesday, June 29, 2021 9:59 AM
To:
[email protected] <
[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon
Ok, thanks, Tony.
On 6/29/21 11:57 AM, Tony_AD0VC wrote:
I have the same situation with a broadcaster about a mile from here and living in the Denver suburbs. I have built many filters and never worried too much about orientation. I tend to lay mine out like the schematic with the series branch inductors at right angles to the shunt branch inductors.
Tony
________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Tuesday, June 29, 2021 9:33 AM
To: [email protected] <[email protected]>
Subject: Re: [softrock40] homemade chebyshev 7th order BB band stop to begin soon
I don't know. There's a broadcast band station about 1.5 mi away that
wreaks havoc on longwave (along with numerous other bb stations but much
further away). It also interferes on higher HF with any preamps.
Haven't heard of the Cauer filter, is there a calculator online for it?
Will take a look.
I was concerned about toroid interaction. I remember reading that close
toroids were supposed to be a certain distance apart and at right angles
to one another? Just wanted to be sure.
Jon
On 6/29/21 11:19 AM, Tony_AD0VC wrote:
Just build it and it will be fine. You probably only need maybe 20 or 30 db of attenuation really. Also, I would recommend the Cauer filter. It will do the job with a lower order and fewer parts.
Tony
________________________________
From: [email protected] <[email protected]> on behalf of JonI via groups.io <ji425bt@...>
Sent: Tuesday, June 29, 2021 8:57 AM
To: [email protected] <[email protected]>
Subject: [softrock40] homemade chebyshev 7th order BB band stop to begin soon
What parts I didn't have are on the way to start construction of the
chebyshev 7th order BB band stop filter. The inductors will be a
combination of ferrite and powdered iron toroids. I'll be using the
ugly duckling or island method to make this and then placing the board
into a metal casing. Since I haven't done anything like this in a
while, I wonder how compact I can get with the toroids, should there be
a certain spacing, orientation, etc? Thanks.
Jon
