[Amps] Building an Amp 101

[Carl]

> ORIGINAL MESSAGE:          (may be snipped)
>
> n 1/18/2014 9:52 AM, Jim Garland wrote:
>> I agree that one shouldn't leave the unused segments of of a tank coil
>> completely floating, and I don't do that. As you suggest, I connect the
>> wiper on the bandswitch to the cold (antenna) end of the inductor so that
>> the switch shorts the unused segments. For esample, if operating 10m, the
>> 15m tap is shorted by the wiper to the 160m tap at the far end of the 
>> coil.
>
> REPLY:
>
> This method works and is commonly used, but there is another way, which I 
> think has some advantages.
>
> I have separate coils for each band. They are NOT magnetically coupled to 
> each other even though they are in series. Each coil is oriented 90 
> degrees to it's neighbor and they alternate vertical and horizontal with 
> each band so the coils do not "see" their neighbor.
>
> The tradeoff is this requires larger coils, since even though they are in 
> series, they have almost no magnetic coupling between them. The advantage 
> is that none of the coils need to be shorted out by the bandswitch and 
> therefore no current flows through the "short". I know this approach will 
> not appeal everybody but it works for me.
>
> 73, Bill W6WRT


>

Brute force survivability, whatever floats your boat is fine by me.

There are many ways to design and build an amp, from neolithic to elegant; I 
fall somewhere between those extremes as do the majority of ham and 
commercial amps.

Carl
KM1H

>