[Lowfer] Class E vs. Class C what's your opinion ?

[k2ors at comcast.net]

Andy,

>I have absolutely NO expertise in this matter; only
>quoting something I read in a net article: The second
>harmonic of a 1 watt LOWfer xmtr will be around 5dB
>down from the fundamental, however the 50 foot antenna
>efficiency being around -39dB down would attenuate the
>2nd harmonic to around the neighborhood of -34dB,
>which if true would be below the -20dB limit.


   Not to worry !  

With such low powers at LF you are lucky if anyone hears your fundamental, let alone harmonics!

I wasn't thinking of you when I made my comments but rather someone else who was proposing to run 
a 100 watt Class-E transmitter without a LPF on the basis that the antenna will be highly reactive off resonance 
and class-E is so efficient that there won't be any energy left for the harmonics.

 I believe that there is definite benefit from a LPF and you certainly need one, especially for a switching type  amplifier!

 I guess the way of quantifying the benefit of a LPF into an antenna is either by measurement as Tom suggests of by 
modeling (SPICE etc).

  I was wondering if anyone has tried to quantify the attenuation of a LPF with anything other than a 50 ohm dummy load.


--
73 Warren K2ORS
WD2XGJ     136-140kHz
WD2XSH/23 505-510kHz
WE2XEB/2   160-189kHz
WE2XGR/1 505-515kHz

FN42hi
http://www.w4dex.com/wd2xgj.htm