X-GM-THRID: 1236905797731265332 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.78.172.1 with SMTP id u1cs175654hue; Sat, 19 May 2007 13:08:11 -0700 (PDT) Received: by 10.67.89.5 with SMTP id r5mr2060209ugl.1179605291117; Sat, 19 May 2007 13:08:11 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id 13si3127176ugb.2007.05.19.13.08.08; Sat, 19 May 2007 13:08:11 -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 1HpVB3-0003Rx-2h for rs_out_1@blacksheep.org; Sat, 19 May 2007 21:05:21 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HpVB2-0003Ro-A2 for rsgb_lf_group@blacksheep.org; Sat, 19 May 2007 21:05:20 +0100 Received: from hexagram.inweb.co.uk ([213.210.47.2]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1HpVB1-0006nd-Fj for rsgb_lf_group@blacksheep.org; Sat, 19 May 2007 21:05:20 +0100 Received: from VicsLaptop (85-211-106-229.dyn.gotadsl.co.uk [85.211.106.229]) by hexagram.inweb.co.uk (Postfix) with SMTP id 8BFD6BC245 for ; Sat, 19 May 2007 21:05:18 +0100 (BST) Message-ID: <00f501c79a50$f60bad10$2101a8c0@VicsLaptop> From: "Vic@VicsFloridaVilla" To: Date: Sat, 19 May 2007 21:04:49 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: LF 500khz Content-Type: multipart/alternative; boundary="----=_NextPart_000_00F2_01C79A59.5660F4B0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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: 1742 This is a multi-part message in MIME format. ------=_NextPart_000_00F2_01C79A59.5660F4B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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.=20 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.=20 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_00F2_01C79A59.5660F4B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Folks,
 
 
Joined the list a couple of = weeks ago amd=20 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 = suppression=20 on ssb - really impressive for 4 IN4148 diodes and a couple of FT50-43 = cores.=20 Plenty of attenuation of 1000khz and 1500khz harmonics. It's looking = good=20 !
 
Just tried it on receive and = it does work=20 but signals very weak. With the K2 pre amp on I can hear MSF 60Khz at = S1 ,=20 Loran 100Khz at S4, BBc R4 198Khz at S9, plus a few other data type sigs = below=20 150khz. Heard nothing on 500Khz . I can hear a strong intermittent data = type=20 signal on about 518Khz Plenty of noise when I connect the = antenna=20 though. Looks like I may need to work on the antenna and maybe some = receive=20 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 for=20 a pa suitable for 500khz. Something around 5 - 10 watts output from = about 1mW=20 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 with=20 the transverter board to drive a transveter ? I can get a full 1mW tx = output=20 into a 50 ohm dummy load (as per the construction manual) but when = driving my=20 homebrew ring mixer I can only get about 0.3 mW maximum. I wonder if = there is an=20 impedance mismatch which is loading the K2 output.  The K2 is = connected=20 directly to the mixer.  My mixer has six trifilar turns on a = FT50-43 at=20 each end. It clearly works well but I think I'll need to get the level = up a bit=20 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 there=20 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
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