Joe, Joe recommends a good set of values to keep on hand for most frequencies that you will be working with. The material type is as important as the size.
For QRP and low power levels , I would say .375 and .500 ( 37 & 50 ) in the part number, size cores will be the ones you use the most of.
If you are in the USA www.kitsandparts.com has a nice selection and calculator for sizes, mixes, and don't forget some different wire sizes maybe in the 22 to 30 wire gauge range magnet type wire.
Also if you do need a special core Amidon in the USA also will sell directly to hams.
Charlie, W5COV On 3/14/2014 10:44 AM, Joe Rocci wrote:
Go to this web site and download the very excellent toroid calculator program. It has all the information you need to deal with different types of toroids.http://www.dl5swb.de/html/mini_ring_core_calculator.htmAlso, be aware that you'll need a good ferrite material for the transformers (type 43 or 61 typical), and low loss powdered iron cores for the filters (type 2 or 6 typical).Joe W3JDR ----- Original Message ----- *From:* hcker2000 <mailto:hcker2000@xxxxxxxxx> *To:* minima@xxxxxxxxxxxxx <mailto:minima@xxxxxxxxxxxxx> *Sent:* Friday, March 14, 2014 11:24 AM *Subject:* [minima] Toroid size? I need to pick up some toroid's for winding. does the size mater? Links to some good sizes would be greatly appreciated.-- Mike "hcker2000" Ashcrafthttp://bigironinteractive.com <http://www.linkedin.com/in/mikeashcraft>
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