Input vs. Output

[Kenneth G. Gordon]

Domenic wrote:

> A warning: efficency also may vary by band.

It does. Higher bands will exhibit lower efficiency.

> If memory is correct on the two 
> HW16's I own the output power on 15 M is under 30 watts (at 90 watts input).

That is correct. My first one's output power was about 15 watts, in fact. The 
reason for that is that the final tank circuit does not actually resonate at any 
point in the tuning of the output cap. And the reason for THAT is that the 
final tank coil has too much inductance.
 
> W7EKB had a mod to change the pi-network by spreading the turns on the tank coil
>  to improve things(I mention it for info I have never tried it, so perform  the
> mod with care).

I was only passing that mod on to everyone who needed it. It was not my 
idea. I think I got it out of an old Hints and Kinks. However, it most definitely 
DOES work. I have done that simple mod to several different HW-16s. Power 
output, once the tank circuit properly resonates, is equal to that available on 
80 and 40. About 50 watts in my case.

However, once you do that, the receiver must be realigned on 15 to match.

> This is not unusual in radios which have a single tapped output tank coil.  This
> often results in a less than optimum L/C ratio on one or more  bands.

Indeed, this is true! :-)

Ken Gordon W7EKB

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