[Elecraft] TUNE power, low vs high

[Bill Frantz]

Many years ago I built a circuit which used op amps to make 
diodes into "perfect rectifiers" -- rectifiers that would be 
linear at very low voltages. Antenna analysers also have the 
same problem. The real problem may be building a rectifier that 
works at very low voltages when at low power and continues to 
work at high voltages when at high power.

Cheers - Bill, AE6JV

sOn 12/12/13 at 6:21 PM, w3fpr at embarqmail.com (Don Wilhelm) wrote:

>If all things are perfect, there would be no difference.  But 
>in the practical, physical world, there are differences.  In 
>the question you have posed, there is the wattmeter diodes to 
>consider.  When the forward voltage is quite small, as would be 
>the case at lower power levels, there may not be enough 
>rectified voltage for a good indication of reverse power - that 
>will lead to erroneous results that may cause higher SWR 
>indications when the power is increased.

-----------------------------------------------------------------------
Bill Frantz        |Security, like correctness, is| Periwinkle
(408)356-8506      |not an add-on feature. - Attr-| 16345 
Englewood Ave
www.pwpconsult.com |ibuted to Andrew Tanenbaum    | Los Gatos, 
CA 95032