X-GM-THRID: 1236915222760736385 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.78.172.1 with SMTP id u1cs178671hue; Sat, 19 May 2007 15:38:00 -0700 (PDT) Received: by 10.67.101.8 with SMTP id d8mr2161954ugm.1179614280012; Sat, 19 May 2007 15:38:00 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id x33si3249763ugc.2007.05.19.15.37.57; Sat, 19 May 2007 15:38:00 -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) DomainKey-Status: bad (test mode) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HpXUU-0003mo-O1 for rs_out_1@blacksheep.org; Sat, 19 May 2007 23:33:34 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HpXUU-0003mf-1u for rsgb_lf_group@blacksheep.org; Sat, 19 May 2007 23:33:34 +0100 Received: from smtp813.mail.ird.yahoo.com ([217.146.188.73]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1HpXUS-0007nt-8S for rsgb_lf_group@blacksheep.org; Sat, 19 May 2007 23:33:33 +0100 Received: (qmail 80247 invoked from network); 19 May 2007 22:33:26 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-YMail-OSG:From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:Importance:X-MimeOLE:In-Reply-To; b=6DKqN53Ymkz/o+8+p5/iRVr1XHIFZEEQwI1kuy8XAIIxrwTQIpLRgStxqxaSrsZeImNn/M8WKvWFAqeyVSORIBmOPRKF9HQ9FM9hBUT4a7fKeyDYWEAamS0uNhWuz3H32q2t98JG5Oe5hZ00/QeddIB3Y82zJ+Q88Wjpp8D1lSY= ; Received: from unknown (HELO aquarids) (ganymede444@btinternet.com@86.134.204.207 with login) by smtp813.mail.ird.yahoo.com with SMTP; 19 May 2007 22:33:26 -0000 X-YMail-OSG: qD.m0cAVM1mjEQWuzKjkZdTzWusXLO2IxmreqL5Ksw_P7xVhhx3AE7Rv7xk6PxtK6yQPgUMd_yRAS694I1FI7zP43pbyNZ2nOJ_c3Q46Kb036.GsZNzPY8TwbQA- From: "Dave G3WCB" To: Date: Sat, 19 May 2007 23:33:55 +0100 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 In-Reply-To: <00f501c79a50$f60bad10$2101a8c0@VicsLaptop> DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: RE: LF 500khz Content-Type: multipart/alternative; boundary="----=_NextPart_000_0018_01C79A6E.2AD1A190" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.8 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_30_40, HTML_FONTCOLOR_BLUE,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 Status: O X-Status: X-Keywords: X-UID: 2120 This is a multi-part message in MIME format. ------=_NextPart_000_0018_01C79A6E.2AD1A190 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi, Vic. I've got no experince with the K2, but you'll probably need a pre-selector to get the best performance out of your rig on 500 kHz. I use a simple design with a fet front end, which can be found on G3YXM's web-site:- http://www.wireless.org.uk/circuits2.htm I substituted a J310 fet for the BF245, and used IFTs from a junked transistor radio for the inductors. My RX is an Icom IC-PCR1000 which is okay, but the IF filter is a bit wide for close-in CW work. For transmitting, I use a design by DF3LP, which was originally for 137 kHz http://www.qsl.net/df3lp/projects/lftx/index.html It uses an IRF 540 FET as the output stage, and I have no trouble getting 25W into 50 ohms from a 12VDC supply, although you may not need this much power to hit the 100 mW ERP limit if you have a reasonable antenna. You can scavenge most of the bits for nothing from scrap PC power supplies, including the case and fan! The DF3LP TX design uses a crystal-mixer VFO, but you could omit this and feed your 1mW straight into the second BC549 transistor. You'd need to re-do the pi-section filters for operation at 500 kHz, but you just need to scale the inductance value by the ratio 137/500. I've got a scanned copy of my TX circuit if you are interested. Quite a few 500 kHz OPS are using valve TXs, with bottles like ECL82, and 2E26s. It just depends what you are happiest using! 73, Dave G3WCB IO91RM -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Vic@VicsFloridaVilla Sent: 19 May 2007 21:05 To: rsgb_lf_group@blacksheep.org Subject: LF: LF 500khz Hi Folks, Joined the list a couple of weeks ago amd enjoying reading all the postings but this is my first posting. I am planning to use my Elecraft K2 to drive a homebrew transverter to give me a 500khz capability. I have the transverter interface board in the K2 so have a 1mW output available. So far I hace lashed up a 28Mhz xtal oscillator and a home brew diode ring mixer. Feeding these through a G0MRF 7 element Low Pass Filter I tested it the other night and it works ! Wow. Nice clean cw and ssb on 500khz (feeding directly into my receiver....probably the first and last time I'll hear ssb on 500khz !!) Amazing carrier suppression on ssb - really impressive for 4 IN4148 diodes and a couple of FT50-43 cores. Plenty of attenuation of 1000khz and 1500khz harmonics. It's looking good ! Just tried it on receive and it does work but signals very weak. With the K2 pre amp on I can hear MSF 60Khz at S1 , Loran 100Khz at S4, BBc R4 198Khz at S9, plus a few other data type sigs below 150khz. Heard nothing on 500Khz . I can hear a strong intermittent data type signal on about 518Khz Plenty of noise when I connect the antenna though. Looks like I may need to work on the antenna and maybe some receive amplification . I'm thrilled with all this so far but now I need some help with the rest of the system. So a few questions for you all, and any ideas and suggestions gratefully received ! 1) Can anyone point me to any designs for a pa suitable for 500khz. Something around 5 - 10 watts output from about 1mW input would be great. I am not very knowledgable on electronics but I love tinkering so something which is easy to get going would be good. I imagine at 500khz it should not be too difficult. 2) Has anyone on the list used a K2 with the transverter board to drive a transveter ? I can get a full 1mW tx output into a 50 ohm dummy load (as per the construction manual) but when driving my homebrew ring mixer I can only get about 0.3 mW maximum. I wonder if there is an impedance mismatch which is loading the K2 output. The K2 is connected directly to the mixer. My mixer has six trifilar turns on a FT50-43 at each end. It clearly works well but I think I'll need to get the level up a bit at some point. 3) Thinking ahead to antennas.....I'll need to do something to resonate my 180 ft Inv L . I 'll probably stick a big loading coil in it somewhere but I have no idea how much L I'll need . Is there any software out there which will help me with this ? Meanwhile I'll press on with the band pass filter which is not working so well . Time for a tinker !! TIA 73, Vic GW4JUN Halkyn North Wales IO83JF ------=_NextPart_000_0018_01C79A6E.2AD1A190 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi,=20 Vic.
 
I've=20 got no experince with the K2, but you'll probably need a pre-selector to = get the=20 best performance out of your rig on 500 kHz. I use a simple design = with a=20 fet front end, which can be found on G3YXM's web-site:- =20 http://www.wireless.org= .uk/circuits2.htm  =20 I substituted a J310 fet for the BF245, and used IFTs from a junked = transistor=20 radio for the inductors. My RX is an Icom IC-PCR1000 which is okay, but = the IF=20 filter is a bit wide for close-in CW work.
 
For=20 transmitting, I use a design by DF3LP, which was originally for 137 kHz=20 http://www.qsl.net/df3lp/projects/lftx/index.html   It uses an IRF 540 FET as the output = stage, and=20 I have no trouble getting 25W into 50 ohms from a 12VDC supply, although = you may=20 not need this much power to hit the 100 mW ERP limit if you have a=20 reasonable antenna.
 
You can scavenge most of the bits for nothing = from=20 scrap PC power supplies, including the case and=20 fan!
 
The DF3LP TX design uses a crystal-mixer VFO, = but you=20 could omit this and feed your 1mW straight into the second BC549 = transistor.=20 You'd need to re-do the pi-section filters for operation at 500 kHz, but = you=20 just need to scale the inductance value by the = ratio 137/500. I've got=20 a scanned copy of my TX circuit if you are=20 interested.
 
Quite a few 500 kHz OPS are using valve TXs, = with=20 bottles like ECL82, and 2E26s. It just depends what you are happiest=20 using!
 
73, Dave G3WCB = IO91RM
 
 
 
-----Original Message-----
From:=20 owner-rsgb_lf_group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of=20 Vic@VicsFloridaVilla
Sent: 19 May 2007 = 21:05
To:=20 rsgb_lf_group@blacksheep.org
Subject: LF: LF=20 500khz

Hi Folks,
 
 
Joined the list a couple of = weeks ago=20 amd enjoying reading all the postings but this is my first=20 posting.
 
I am planning to use my = Elecraft K2 to=20 drive a homebrew transverter to give me a 500khz capability. I have = the=20 transverter interface board in the K2 so have a 1mW output=20 available.
 
So far I hace lashed up a = 28Mhz xtal=20 oscillator and a home brew diode ring mixer. Feeding these through a = G0MRF 7=20 element Low  Pass Filter I tested it the other night and it works = ! Wow.=20 Nice clean cw and ssb on 500khz (feeding directly into my = receiver....probably=20 the first and last time I'll hear ssb on 500khz !!) Amazing carrier=20 suppression on ssb - really impressive for 4 IN4148 diodes and a = couple of=20 FT50-43 cores. Plenty of attenuation of 1000khz and 1500khz harmonics. = It's=20 looking good !
 
Just tried it on receive = and it does=20 work but signals very weak. With the K2 pre amp on I can hear MSF = 60Khz at=20 S1 , Loran 100Khz at S4, BBc R4 198Khz at S9, plus a few other = data type=20 sigs below 150khz. Heard nothing on 500Khz . I can hear a strong = intermittent=20 data type signal on about 518Khz Plenty of noise when I = connect the=20 antenna though. Looks like I may need to work on the antenna and maybe = some=20 receive amplification .
 
I'm thrilled with all this = so far =20 but now I need some help with the rest of the system.
 
So a few questions for you = all, and any=20 ideas and suggestions gratefully received !
 
1) Can anyone point me to = any designs=20 for a pa suitable for 500khz. Something around 5 - 10 watts output = from about=20 1mW input would be great. I am not very knowledgable on electronics = but I love=20 tinkering so something which is easy to get going would be good. I = imagine at=20 500khz it should not be too difficult.
 
2) Has anyone on the list = used a K2=20 with the transverter board to drive a transveter ? I can get a full = 1mW tx=20 output into a 50 ohm dummy load (as per the construction manual) but = when=20 driving my homebrew ring mixer I can only get about 0.3 mW maximum. I = wonder=20 if there is an impedance mismatch which is loading the K2 = output.  The K2=20 is connected directly to the mixer.  My mixer has six trifilar = turns on a=20 FT50-43 at each end. It clearly works well but I think I'll need to = get the=20 level up a bit at some point.
 
3) Thinking ahead to = antennas.....I'll=20 need to do something to resonate my 180 ft Inv L . I 'll probably = stick a big=20 loading coil in it somewhere but I have no idea how much L I'll need . = Is=20 there any software out there which will help me with this = ?
 
Meanwhile I'll press on = with the band=20 pass filter which is not working so well . Time for a tinker = !!
 
TIA
 
73,
 
Vic GW4JUN
 
Halkyn North Wales=20 IO83JF
------=_NextPart_000_0018_01C79A6E.2AD1A190--