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

[Bill Ashlock]

> With such low powers at LF you are lucky if anyone hears your fundamental, let alone harmonics!
 
Warren
 
If ya haven't tried, it don't knock it!  :)  :)
 
I'm out of here. See you all next week when I return from the frozen north.
 
Bill> From: k2ors at comcast.net> To: lowfer at mailman.qth.net> Subject: [Lowfer] Class E vs. Class C what's your opinion ?> Date: Fri, 1 Feb 2008 02:49:48 +0000> > 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> _______________________________________________> >From the Lowfer mailing list> Send messages to: Lowfer at mailman.qth.net> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer