John
I always used SQUARE WAVE to drive my class D es E amps. The Decca 5501
modules input is Sine or Sq wave, the input cct shapes the sine wave to Sq
de mal/g3kev
-----Original Message-----
From: John Rabson
Sent: Sunday, November 27, 2016 10:28 AM
To: [email protected]
Subject: Re: LF: H Bridge power MOSFET based amps question
My experiences with class E single ended amplifiers is similar to that
reported by Mal. The only caveat I would add is that you should be quite
sure that you have the right driving waveform. During my early experiments
with a design based on G3NYK’s spreadsheet I tried a sine wave rather than
the square wave it should have had. The result was lower efficiency and a
short life for the FET.
John F5VLF
On 26 Nov 2016, at 11:35, mal hamilton <[email protected]> wrote:
Chris
The Decca 5501 amp modules use a H bridge class D configuration followed
by a series resonant PA circuit and this is probably one of the most
reliable amplifiers about. Use suitable rated FET'S to give the desired RF
output.
Also the protection cct used avoids disaster in the event of an antenna
failure short/open cct,
I have built lots of class D 1Kw push pull amps over the years for LF/MF
but they are vunerable to damage with load variations whereas the Decca
bridge amps survive. I never had a failure with the Decca, and have been
using them for many years.
Another approach which is worth a consideration is the class E amp single
ended, these are very reliable and avoids the crossover switching problems
with the push pull system. Setting up procedure is critical but there
after very stable,
Hope these observations help you
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