[AMPS] Coil heating

[measures]

>
>> The curious part of this whole business was the location of the heating.
>> With turns on BOTH sides of the tap involved, I have to wonder what,
>> exactly, was going on there. In the past, when I've melted down tank coils,
>> the heating (and deformation) was confined to the center of the active area
>> of the coil. Has anyone else seen this effect?
>>
>IMO, the heating was at the tap point, spreading out each way. Chances are
>the "black" area would have spread with time.
>
>There has been mention on the reflector of directing cooling air on a coil
>to prevent "melt down." This does nothing about the losses due to under-
>engineering. RF is being converted into heat and does not reach the antenna.
>Heat can be eliminated by selecting the proper components for the job to
>be done. 

Copper has a positive temp. coefficient.  The hotter it gets, the more 
resistance.  Cooling air is helpful.  

> Hans and I are in agreement....there is a limit to how small you can
>make an RF deck.
>
>The same is true about band switches. One must take into consideration not
>only the voltage and current rating, but also the distance between contacts
>when selecting the proper component.
>
€  Measuring the actual withstanding voltage is not a bad idea.  

cheers, Phil
>
>
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>


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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