Return-Path: Received: from mtain-di02.r1000.mx.aol.com (mtain-di02.r1000.mx.aol.com [172.29.64.6]) by air-mc07.mail.aol.com (v129.4) with ESMTP id MAILINMC073-a97d4c20d680130; Tue, 22 Jun 2010 11:28:00 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-di02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6D93538000109; Tue, 22 Jun 2010 11:27:55 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OR5MI-0004BO-Ih for rs_out_1@blacksheep.org; Tue, 22 Jun 2010 16:25:54 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OR5MH-0004BF-4P for rsgb_lf_group@blacksheep.org; Tue, 22 Jun 2010 16:25:53 +0100 Received: from out1.ip03ir2.opaltelecom.net ([62.24.128.239]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OR5MF-0001oU-11 for rsgb_lf_group@blacksheep.org; Tue, 22 Jun 2010 16:25:53 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av0EALpyIExcEYOE/2dsb2JhbACPLwOPZXHBS4UbBA X-IronPort-AV: E=Sophos;i="4.53,460,1272841200"; d="scan'208,217";a="308833225" Received: from unknown (HELO your91hoehfy9g) ([92.17.131.132]) by out1.ip03ir2.opaltelecom.net with SMTP; 22 Jun 2010 16:25:38 +0100 Message-ID: <001f01cb121f$2b3d12a0$0301a8c0@your91hoehfy9g> From: "mal hamilton" To: References: <000c01cb11dc$2b310020$0401a8c0@xphd97xgq27nyf> <3A2133327AFB454CAC336E25F96F4352@TonyLaptop> Date: Tue, 22 Jun 2010 16:25:38 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: Re: 137 Revival Content-Type: multipart/alternative; boundary="----=_NextPart_000_001C_01CB1227.8CCAB330" 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_30_40,HTML_MESSAGE 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 x-aol-global-disposition: G x-aol-sid: 3039ac1d40064c20d67b47ab X-AOL-IP: 193.82.116.20 ------=_NextPart_000_001C_01CB1227.8CCAB330 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tony The G3YXM design some years back was reliable, two versions one for 12= v and the other for 100v. My 137 kcs TX is similar but with several fa= il safe features added. The set up in my case is a IC706 on 13.7 Mcs, divider network down to= 137 Kcs, driver tc4426 chip, 4 FET PA, matching transformer to 50 ohm= s, LPF. RF from TX fed via 50ohm cable to antenna some 100 yards away in a fie= ld, loading coil at base of antenna approx 0.5 mH matched and resonate= d to 50 ohm feed.=20 Monitor SWR and DC current to PA at all times during TX in case anythi= ng goes wrong.=20 Fortunately in my case the system is reliable and stable. During storm= y wx beware of SWR fluctuations and drawing excessive current that mig= ht cause the PA FETS to expire, especially if using vy slow QRS MODE I normally work CW normal speed and seldom go slower than QRS 3.=20 This is a class D pa On 500 Kcs I use a different sort of TX, which is class E single ended= FET, which would also work on 137 Kcs with different values for L and= C.I built this TX in a few hours and it has proved totally reliable= after a number of years use, designed for 50 ohms and fed to a 1/4 wa= ve inv L antenna at 100 ft high There are plenty of designs about for class D and E transmitters suita= ble for LF/MF on the web De mal/g3kev =20 . ----- Original Message -----=20 From: Tony Baldwin=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, June 22, 2010 11:49 AM Subject: LF: Re: 137 Revival I fully intend to be QRV on 137 by the winter. On that note, can anyone recommend a reliable foolproof transmitter= that uses easily available components ? Tony, EI8JK. ----- Original Message -----=20 From: mal hamilton=20 To: rsgb=20 Sent: Tuesday, June 22, 2010 8:26 AM Subject: LF: 137 Revival LF How about a 137 kcs Revival, much more interesting than 500, which= is more like 160 metres. CW, QRSCW, Invisible Ros etc G3KEV ------=_NextPart_000_001C_01CB1227.8CCAB330 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tony
The G3YXM design some years back was= reliable, two=20 versions one for 12v and the other for 100v. My 137 kcs TX is similar= but with=20 several fail safe features added.
The set up in my case is a IC706 = ;on 13.7 Mcs,=20 divider network down to 137 Kcs, driver tc4426 chip, 4 FET PA, ma= tching=20 transformer to 50 ohms, LPF.
RF from TX fed via 50ohm cable to ant= enna some 100=20 yards away in a field, loading coil at base of antenna approx 0.5 mH= =20 matched and resonated to 50 ohm feed.
Monitor SWR and DC current to PA at= all times=20 during TX in case anything goes wrong.
Fortunately in my case the system is= reliable and=20 stable. During stormy wx beware of SWR fluctuations and drawing excess= ive=20 current that might cause the PA FETS to expire, especially if using vy= slow QRS=20 MODE
I normally work CW normal speed and= seldom go=20 slower than QRS 3.
This is a class D pa
 
On 500 Kcs I use a different sort of= TX, which is=20 class E single ended FET, which would also work on 137 Kcs with differ= ent values=20 for L and C.I built this TX&nb= sp;in a few=20 hours and it has proved totally reliable after a number of years= use,=20 designed for 50 ohms and fed to a 1/4 wave inv L antenna at 100= ft=20 high
There are plenty of designs about for= class D and E=20 transmitters suitable for LF/MF on the web
De mal/g3kev
 
.
 
----- Original Message -----
From:=20 Tony Baldwin=
Sent: Tuesday, June 22, 2010= 11:49=20 AM
Subject: LF: Re: 137 Revival<= /DIV>

I fully intend to be QRV on 137 by= the=20 winter.
On that note, can anyone recommend= a reliable=20 foolproof transmitter that uses easily available components ?=
 
Tony, EI8JK.
 
----- Original Message -----
From:=20 mal=20 hamilton
To: rsgb
Sent: Tuesday, June 22, 201= 0 8:26=20 AM
Subject: LF: 137 Revival

LF
How about a 137 kcs Revival, much= more=20 interesting than 500, which is more like 160 metres.
CW, QRSCW, Invisible Ros etc
G3KEV
 
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