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The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi Joe, Class E is fascinating and can be high efficient, 98% or so. However the output impedance has to be quite exactly 50 Ohm +-j0! A SWR of 1.5 can reduce the efficiency significantly so that all the advantages of the class E design are lost. Thus, i'm using class-D designs. I have 2 PAs for 630m. A small one running at 12 VDC, https://dl.dropboxusercontent.com/u/19882028/MF/100W-475KHZ-PA.png and https://dl.dropboxusercontent.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.JPG and a large one giving 0...1.2 kW, running as a H bridge, switching directly at 320V DC. The efficiency can easily reach more than 90% too. For you, i assume a normal class D using 2 (or 2x2) FETs against ground, using a ferrite output transformer may be the best choice. This design is used by many active MF stns, i know. What power range do you inted to realise? [...] Content analysis details: (-2.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [129.206.210.211 listed in list.dnswl.org] -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 3b8620872b19e25fb6f4dfaf1256edc3 Subject: Re: LF: VO1NA_OK2BVG Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Hi Joe, Class E is fascinating and can be high efficient, 98% or so. However the output impedance has to be quite exactly 50 Ohm +-j0! A SWR of 1.5 can reduce the efficiency significantly so that all the advantages of the class E design are lost. Thus, i'm using class-D designs. I have 2 PAs for 630m. A small one running at 12 VDC, https://dl.dropboxusercontent.com/u/19882028/MF/100W-475KHZ-PA.png and https://dl.dropboxusercontent.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.JPG and a large one giving 0...1.2 kW, running as a H bridge, switching directly at 320V DC. The efficiency can easily reach more than 90% too. For you, i assume a normal class D using 2 (or 2x2) FETs against ground, using a ferrite output transformer may be the best choice. This design is used by many active MF stns, i know. What power range do you inted to realise? 73, Stefan/DK7FC Am 28.03.2014 00:24, schrieb jcraig@mun.ca: > Hi Stefan, > > I have some IRFP140BPF hexfets. Using Alan's G3NYK Class E > design spreadsheet for 200 watts at 13.8 Vdd gives 144 and 119 nf > for C1 and C2 and 1.14 uH for L. I have used silver mica for C1 and C2 > but these are expensive. What do you use? I remember mentioned your > class e experiments. > > 73 > Joe > > On Wed, 26 Mar 2014, Stefan Schäfer wrote: > >> >> Am 26.03.2014 19:36, schrieb jcraig@mun.ca: >>> Perhaps some day I will QRO! >>> >>> Joe >> >> Yes, please :-) >> >> 73, Stefan >> >>