Toroids work but be sure to dedicate only one toroid per band - don't share
the bands fractionally.
I made a mistake in my first build sharing one toroid for 40/80 duty. On
40, the few turns covering only a faction of the core results in local flux
density way too high leading to excess heating around those wraps as a
result. Efficiency is off quite a bit as well.
I'm sure Carl and the other seasoned guys would not have made that mistake
but I have not see the subject mentioned otherwise.
Good luck.
73/jeff/ac0c
www.ac0c.com
--------------------------------------------------
From: "Carl" <km1h@jeremy.mv.com>
Sent: Friday, July 30, 2010 5:31 PM
To: "Roger" <sub1@rogerhalstead.com>; <amps@contesting.com>
Subject: Re: [Amps] winding toroids
>>
>> On 7/30/2010 1:46 PM, Mike Lord wrote:
>>> When winding toroids is there any reason (other than mechanical
>>> stability) why stranded wire can not, or should not be used?
>>>
>> I have two amplifiers, and one antenna that use toroids. All use
>> stranded wire on one of the toroids including one rather large toroid in
>> the Emtron amp.
>>
>> 73
>>
>> Roger (K8RI)
>>>
>>> Thanks, Mike K4ELV
>
> The most readily available Teflon wire is stranded and has been used in
> commercial ham and homebrew amps especially since we got the 1500W limit
> on
> 160. Alpha was a very early user of toroids in amps.
>
> Carl
> KM1H
>
>
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>
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