Return-Path: Received: from mtain-me11.r1000.mx.aol.com (mtain-me11.r1000.mx.aol.com [172.29.96.147]) by air-di01.mail.aol.com (v126.13) with ESMTP id MAILINDI013-eab84b60b6e422a; Wed, 27 Jan 2010 16:57:56 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-me11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5E83A380001D6; Wed, 27 Jan 2010 16:57:53 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NaFsk-0006Se-GB for rs_out_1@blacksheep.org; Wed, 27 Jan 2010 21:57:02 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NaFsj-0006SU-TQ for rsgb_lf_group@blacksheep.org; Wed, 27 Jan 2010 21:57:01 +0000 Received: from fg-out-1718.google.com ([72.14.220.152]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NaFsh-0007Qy-Dc for rsgb_lf_group@blacksheep.org; Wed, 27 Jan 2010 21:57:01 +0000 Received: by fg-out-1718.google.com with SMTP id e21so153972fga.10 for ; Wed, 27 Jan 2010 13:56:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=BiHQh72lv4FRaHAGQ1URiW/uPZCYwiRG5j/48o8xDL4=; b=pnooeQQr0zIZvmnzjyNRnkpoZLr1X5pQeqtvKfdu51DQqJjzS7T5yngpkzCxyZpTFJ UMSF8IystZR5g4TpnmyBWm9y/0fErU5V8NaFzIX5swFLY7gvBn0wgySg8GLJjJGcIdL4 TFW0UD4A9MLS8e51iifXNx/pFfAMiKl1Sk0RM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=vY+HDj7rnyT5fGjnPPD6xp80dnWs4JGjc3oahLI9WorLkLXLsTSfu23xEa1hxyRYCQ TJt9pTZLnaTslIAmUC8fQwzN0ox5+rlLgDL56enfFcA/ImBkOQ8vGzb4zCZsG5hFHtRQ nFD/QE/IHGKfN+OD846H5cJJyXA/0rPRWN8AA= MIME-Version: 1.0 Received: by 10.239.150.4 with SMTP id l4mr1095126hbb.6.1264629418177; Wed, 27 Jan 2010 13:56:58 -0800 (PST) In-Reply-To: References: <1f0624b91001271133g22391461tfa8dc9a87c8f14d4@mail.gmail.com> <1f0624b91001271303v1eb7094bp659dba8418585e81@mail.gmail.com> Date: Wed, 27 Jan 2010 21:56:58 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: RE: 500 kHz JT4A Content-Type: multipart/alternative; boundary=001485f630d03e3783047e2c7b03 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: 3039ac1d60934b60b6e146ca X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --001485f630d03e3783047e2c7b03 Content-Type: text/plain; charset=ISO-8859-1 I was looking at driving push-pull transmitters from fundamental drive signals quite recently. How about a frequency doubler? The output doesn't have to have 1:1 mark-space ratio as it only clocks a flip-flop. And simple doubler can consists of a delay line (CR network with around 0.5us time constant) followed by a squarer to give a resulting waveform shifted in phase from the 500kHz drive signal. Then apply this one, along with the original to a two input XOR gate whose output will then consists of a 1MHz train suitable for dividing by 2 for a perfect 1:1 squarewave drive. Andy www.g4jnt.com This email has been scanned for damaging side-effects by the health and safety police, is guaranteed to contain no substances hazardous to health, but may contribute to dissolving the nether and polar regions 2010/1/27 Rik Strobbe > Gary, > > the SNR values over the last hour or so varied between -2 and -13dB. > Assuming a -24dB limit and your current power (50W) anything above 5W would > provide solid copy and 0.5W occasional copy. > Impressive. > I should get QRV on JT4A, but I blew the transformer of my "straight" 100W > PA, and my 250W G3YXM-clone PA needs 1MHz drive (at TTL level), so I cannot > use that with my HF/500kHz transverter. > > 73, Rik ON7YD - OR7T > ------------------------------ > *Van:* owner-rsgb_lf_group@blacksheep.org [ > owner-rsgb_lf_group@blacksheep.org] namens Gary - G4WGT [ > g4wgt@tiscali.co.uk] > *Verzonden:* woensdag 27 januari 2010 22:03 > *Aan:* rsgb_lf_group@blacksheep.org > *Onderwerp:* Re: LF: RE: 500 kHz JT4A > > Rik, & Andy, > > Thanks for your report & comments & Andy for answering Rik's query. > > Well there has not been any response to my CQ call so I will change the > text to beacon & continue to see if there is a report from further afield. > > If you want to try for a weak decode I can reduce the power for a short > period say 30 minutes, my power is 50 watt RF (200 mW ERP) at the moment so > in view of your good report I could take it down to 10 watts RF. > > Let me know. > > 73, Gary - G4WGT - IO83qo > > 2010/1/27 Andy Talbot > >> -24dB S/N (2.5kHz ) is usually guaranteed >> >> Andy >> www.g4jnt.com >> >> This email has been scanned for damaging side-effects by the health and >> safety police, is guaranteed to contain no substances hazardous to health, >> but may contribute to dissolving the nether and polar regions >> >> >> 2010/1/27 Rik Strobbe >> >> Gary, >>> >>> solid copy here, SNR -5 to -7dB. >>> But the signal is clearly audible, CW would be armchair copy. >>> Any idea down to what SNR values JT4A produces a usable decoding ? >>> >>> 73, Rik ON7YD - OR7T >>> ------------------------------ >>> *Van:* owner-rsgb_lf_group@blacksheep.org [ >>> owner-rsgb_lf_group@blacksheep.org] namens Gary - G4WGT [ >>> g4wgt@tiscali.co.uk] >>> *Verzonden:* woensdag 27 januari 2010 20:33 >>> *Aan:* Rsgb_Lf_Group >>> *Onderwerp:* LF: 500 kHz JT4A >>> >>> LF, >>> >>> Running JT4A this evening on 503.600 kHz, dial frequency 502.300 kHz USB. >>> >>> 73, Gary - G4WGT - IO83qo >>> >> >> > --001485f630d03e3783047e2c7b03 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
I was looking at driving push-pull transmitters from fundamental driv= e signals quite recently.=A0=A0
=A0
How about a frequency doubler?=A0=A0=A0 The output doesn't have= to have 1:1 mark-space ratio as it only clocks a flip-flop.=A0=A0 And=A0s= imple doubler can consists of a delay line (CR network with around 0.5us= time constant) followed by a squarer to give a resulting waveform shifted= in phase from the 500kHz drive signal.=A0 Then apply this one,=A0=A0along= with the original to a two input=A0XOR gate whose output will then consis= ts of a 1MHz train suitable for dividing by 2 for a perfect 1:1 squarewave= drive.
=A0

Andy
www.g4jnt.= com

This email has been scanned for damaging side-effects by th= e health and safety police, is guaranteed to contain no substances hazardo= us to health, but may contribute to dissolving the nether and polar region= s


2010/1/27 Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
Gary,<= /font>
=A0
the SNR values over the= last hour or so varied between -2 and -13dB.
Assuming a -24dB limit= and your current power (50W) anything above 5W would provide solid copy= and 0.5W occasional copy.
Impressive.
I=A0should get QRV on JT= 4A, but I blew the transformer of my "straight" 100W PA,=A0and= my 250W G3YXM-clone PA needs 1MHz drive (at TTL level), so I cannot use= that with my HF/500kHz transverter.
=A0
73, Rik=A0 ON7YD - OR7T<= /font>
Van: owner-rsgb_lf_group@blacksheep.org [owner-rs= gb_lf_group@blacksheep.org] namens Gary - G4WGT [g4wgt@tiscali.co.uk]
Verzonden: woensdag 27 januari 2010 22:03
Aan: rsgb_lf_gr= oup@blacksheep.org
Onderwerp: Re: LF: RE: 500 kHz JT4A

Rik, & Andy,=20

Thanks for your report & comments & Andy for answering Rik= 9;s query.

Well there has not been any response to my CQ call so I will change= the text to beacon & continue to see if there is a report from furthe= r afield.

If you want to try for a weak decode I can reduce the power for a sho= rt period say 30 minutes, my power is 50 watt RF (200 mW ERP) at the momen= t so in view of your good report I could take it down to 10 watts RF.

Let me know.

73, Gary - G4WGT - IO83qo

2010/1/27 Andy Talbot <andy.g4jnt@go= oglemail.com>
-24dB S/N (2.5kHz )=A0 is usually guaranteed

Andy
www.g4jnt.com

This email has been scanned for damaging= side-effects by the health and safety police, is guaranteed to contain no= substances hazardous to health, but may contribute to dissolving the neth= er and polar regions


2010/1/27 Rik Strobbe <Rik.Strobbe= @fys.kuleuven.be>=20

Gary,<= /font>
=A0
solid copy here, SNR -5= to -7dB.
But the signal is clearl= y audible, CW would be armchair copy.
Any idea down to what SN= R values JT4A produces a usable decoding ?
=A0
73, Rik=A0 ON7YD - OR7T<= /font>
Van: owner-rsgb_lf_group@blacksheep.= org [owner-rsgb_lf_group@blacksheep.org] namens Gary - G4WGT [g4wgt@tiscali.co.uk= ]
Verzonden: woensdag 27 januari 2010 20:33
Aan: Rsgb_Lf_Gr= oup
Onderwerp: LF: 500 kHz JT4A

LF,=20

Running JT4A this evening on 503.600 kHz, dial frequency 502.300 kHz= USB.

73, Gary - G4WGT - IO83qo
<= /div>


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