[Amps] Real time tests to see if an RF transformer is saturating?

[Jim Brown]

On Mon,5/15/2017 5:59 AM, Alan Ibbetson wrote:
> The pros don't use designators like FT240-78. Those are numbers from 
> the USA reseller Amidon. You have to search on www.fair-rite.com for 
> the long string of digits (like 5978003801) and type that into the 
> Mouser or RS search box. 

Right.

> Finding the right part on Fair-rite is a pig. There are drop downs 
> under Products on the home page but it's never easy.

Actually it IS easy if you understand how ferrite materials work and 
take the time to study Fair-Rite's EXCELLENT website -- indeed, their 
published data is among the top five companies I've dealt with in five 
decades as an engineer.

>
> If I was in your shoes I'd try type 78 and wind on as many turns in a 
> 5:7 ratio as will fit. As Manfred says, several strands of thinner 
> wire bundled together will be easier to wind and have a bit less 
> copper loss.


Depending on the application, #78 is not a very good material for use as 
a transformer.

Nearly ten years ago, I produced a tutorial on how ferrite materials 
work, and a few years later, it was incorporated into the ARRL Handbook. 
k9yc.com/RFI-Ham.pdf  Among other things, it shows how to view detailed 
specs for individual parts and ferrite materials on the Fair-Rite 
website and in their catalog.

73, Jim K9YC