[Amps] how to wind an HF broadband 10:1 transformer

[jeremy-ca]

Anyone can paint a toroid and without measuring the inductance of a few 
turns and running the math you have no positive idea what you have. Red and 
yellow are Micrometal #2 and #6 mix respectively.

It is possible to wind a 2-30 MHz balun with #2 mix but great care needs to 
be taken in sizing the core, the turns as well as the ratio and minimizing 
capacity at the higher frequencies.

Formulas are in the ARRL HB, on line at several places, Micrometals url, 
etc. Google is your best friend.

Carl
KM1H


Carl
KM1H

----- Original Message ----- 
From: "Dan Sawyer" <dansawyer at earthlink.net>
To: "jeremy-ca" <km1h at jeremy.mv.com>
Cc: "Amps" <Amps at contesting.com>
Sent: Sunday, February 24, 2008 6:10 PM
Subject: Re: [Amps] how to wind an HF broadband 10:1 transformer


> Thanks for the reply,
>
> I am experimenting reworking a Heathkit 104 (not A) front end. That front 
> end had a reputation for being deaf. I believe it was due in large part to 
> a gross impedance mismatch between the filters and the dual gate mosfet.
>
> How does this relate to 'red' or 'yellow' and 47 or 61? I have red and 
> yellow toroids. Experimenting with red seems to work on 40 meters, however 
> it did not work well on higher frequencies. I do not have data handy for 
> these materials.
>
> I was pleased that the experiment worked well on 40.
>
> Dan
>
> jeremy-ca wrote:
>> Iron powder #2 mix is most commonly used in broadband baluns between an 
>> antenna tuner and open wire line.
>>
>> Carl
>> KM1H
>>
>>
>>
>>
>> ----- Original Message ----- From: "Dan Sawyer" <dansawyer at earthlink.net>
>> To: "Amps" <Amps at contesting.com>
>> Sent: Sunday, February 24, 2008 2:48 PM
>> Subject: [Amps] how to wind an HF broadband 10:1 transformer
>>
>>
>>> All,
>>>
>>> I would like to wind a broad band HF, 160 to 10, transformer.
>>>
>>> What core material is best for this range?
>>>
>>> Is the way to wind this a trifler winding (9:1) in an autotransformer
>>> configuration?
>>>
>>> Thanks,
>>>
>>> Dan kb0qil
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>