X-GM-THRID: 1237139710949514374 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.78.172.1 with SMTP id u1cs276486hue; Tue, 22 May 2007 09:08:12 -0700 (PDT) Received: by 10.67.101.10 with SMTP id d10mr682812ugm.1179850091938; Tue, 22 May 2007 09:08:11 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id e33si1918871ugd.2007.05.22.09.08.09; Tue, 22 May 2007 09:08:11 -0700 (PDT) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HqWnO-0007S9-8r for rs_out_1@blacksheep.org; Tue, 22 May 2007 17:01:10 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HqWnN-0007S0-Rf for rsgb_lf_group@blacksheep.org; Tue, 22 May 2007 17:01:09 +0100 Received: from imo-d22.mx.aol.com ([205.188.144.208]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1HqWnK-0008K7-Sj for rsgb_lf_group@blacksheep.org; Tue, 22 May 2007 17:01:09 +0100 Received: from ColePe@aol.com by imo-d22.mx.aol.com (mail_out_v38_r9.2.) id l.bf7.17023e26 (43931) for ; Tue, 22 May 2007 12:00:54 -0400 (EDT) From: ColePe@aol.com Message-ID: Date: Tue, 22 May 2007 12:00:53 EDT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 9.0 SE for Windows sub 5022 X-Spam-Flag: NO X-Spam-Score: 0.6 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,NO_REAL_NAME=0.55 Subject: Re: LF: Re: 500kHz Content-Type: multipart/alternative; boundary="-----------------------------1179849653" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_40_50,HTML_MESSAGE, NO_REAL_NAME 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 Status: O X-Status: X-Keywords: X-UID: 796 -------------------------------1179849653 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Another approach - as I have a number of crystals at the low end of 3.5 MHz and TTL devices in the junk box I built a 7400 oscillator feeding a 7490 decade counter wired to divide by 7. Although the mark/space ratio of the 7490 output is far from ideal I was surprised at how easy it was to get a clean looking 500kHz sine wave with a very simple filter. Peter, G3JFS In a message dated 22/05/2007 10:03:24 Greenwich Standard Time, g3kev.ham@virgin.net writes: It is so easy to get on 500. RE-Easy Start Xtal osc 5 mhz/div by 10/fet driver chip and fet pa in class E. A couple of hrs to build from the junk box. The psu can be the common 13.8v at a couple of amps max. Keep it simple. G3KEV ----- Original Message ----- From: _lawrence mayhead_ (mailto:laurie.mayhead@googlemail.com) To: _rsgb_ (mailto:rsgb_lf_group@blacksheep.org) Sent: Monday, May 21, 2007 2:58 PM Subject: LF: 500kHz Hi Vic, Re. Linear Amp, have a look at design by SM0VPO (Ten Watt Linear Amplifier ) just Google, should find it. I use his basic design just put a few more turns on inductors. 73 Hope see you on 500. Laurie G3AQC. -------------------------------1179849653 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Another approach - as I have a number of crystals at the low end of 3.5= =20 MHz and TTL devices in the junk box I built=20 a 7400 oscillator feeding a 7490 decade counter wired to divi= de=20 by 7.  Although the mark/space ratio of the 7490 output is far from=20 ideal I was surprised at how easy it was to get a clean=20 looking 500kHz sine wave with a very simple filter.
Peter, G3JFS
 
 
 
In a message dated 22/05/2007 10:03:24 Greenwich Standard Time,=20 g3kev.ham@virgin.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
It is so easy to get on 500.
RE-Easy Start
Xtal osc 5 mhz/div by 10/fet driver chip=20= and fet=20 pa in class E.
A couple of hrs to build from the junk bo= x.=20
The psu can be the common 13.8v at a coup= le of=20 amps max.
Keep it simple.
G3KEV
 
----- Original Message -----
Fr= om:=20 lawrence mayhead
To: rsgb
Sent: Monday, May 21, 2007 2:58=20 PM
Subject: LF: 500kHz

Hi Vic,
Re. Linear Amp, have a look at design by SM0VP= O=20 (Ten Watt Linear Amplifier )
just Google, should find it.
I use hi= s=20 basic design just put a few more turns on inductors.
73 Hope see you=20= on=20 500.
Laurie G3AQC.
 
-------------------------------1179849653--