Return-Path: Received: from mtain-di10.r1000.mx.aol.com (mtain-di10.r1000.mx.aol.com [172.29.64.14]) by air-mb02.mail.aol.com (v128.3) with ESMTP id MAILINMB021-a18f4bd5f2939f; Mon, 26 Apr 2010 16:07:47 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-di10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 10A46380000C9; Mon, 26 Apr 2010 16:07:45 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O6UZC-0001y8-Ag for rs_out_1@blacksheep.org; Mon, 26 Apr 2010 21:06:06 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O6UZB-0001xz-EK for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 21:06:05 +0100 Received: from mtaout01-winn.ispmail.ntl.com ([81.103.221.47]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O6UZ9-0004bZ-LV for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 21:06:05 +0100 Received: from know-smtpout-4.server.virginmedia.net ([62.254.123.1]) by mtaout01-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20100426200557.CTUA14666.mtaout01-winn.ispmail.ntl.com@know-smtpout-4.server.virginmedia.net> for ; Mon, 26 Apr 2010 21:05:57 +0100 Received: from [86.31.209.27] (helo=desktop) by know-smtpout-4.server.virginmedia.net with esmtp (Exim 4.63) (envelope-from ) id 1O6UZ2-0001sv-48 for rsgb_lf_group@blacksheep.org; Mon, 26 Apr 2010 21:05:56 +0100 From: "James Cowburn" To: References: Date: Mon, 26 Apr 2010 21:05:54 +0100 Message-ID: <005201cae57b$e1632630$0217aac0@desktop> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 In-Reply-To: Thread-Index: AcrlZtLTJShXJd9DTE+oIkzPtXRADQAEy2jQ X-Cloudmark-Analysis: v=1.1 cv=ZtHxNT4mZm3rCuM0SmWmgWxeBwJsziC8EqOrwwVkrhA= c=1 sm=0 a=iCs-r9iyADEA:10 a=8RloEfZUAAAA:8 a=F3M5lZpKAAAA:8 a=baKWygXw9Shgc4P3-d4A:9 a=9dDBxK5gVNU3TNWClY8A:7 a=6sSiRj-QpwzvU-KFPdl8aLTAkXoA:4 a=CjuIK1q_8ugA:10 a=O58u2wXj750A:10 a=wk6s2zzMB60A:10 a=JRPjeSsSJW33A1nA:21 a=ZxhYRv2gSw5b4ufi:21 a=SSmOFEACAAAA:8 a=Eo4xPVk08_Y0m6Goo3kA:9 a=rDFhmQMjUusb31fNOegA:7 a=dE2UhDkGGOgoThiuyaYt9cIoLT4A:4 a=avkZy_3vLq-TFGRc:21 a=MAJ27icIIVfVMKk7:21 a=HpAAvcLHHh0Zw7uRqdWCyQ==:117 X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_FONT_BIG=0.256,HTML_MESSAGE=0.001 Subject: LF: RE: Probably not a new question... Content-Type: multipart/alternative; boundary="----=_NextPart_000_0053_01CAE584.43278E30" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=EXCUSE_16,HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_FONT_BIG,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: 3039ac1d400e4bd5f2913728 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0053_01CAE584.43278E30 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi Daniele If you can find them, then I can recommend the early models of JRC receivers. I have two NRD515s and a NRD505 and they are all excellent at MF/LF. I also have an ex marine comms RX from JRC, the NRD72H and that's quite good too. Often on Ebay are the Datong VLF upconverters to 28MHz IF. These are excellent and I run one too. Tx wise I have used both an IC735 and an IC706 Mk2g on 500 with good effect (CW QSO's out to 500km and WSJT/WSPR/data out to 1300km). Both will generate around 15W of RF at 500khz after the diode snip mods for MARS/CAP/5MHz and 7.2MHZ. With the IC735 you need to be looking for a later serial number model in the black box, the earlier ones in white boxes with green writing don't like working down at 500 as much and only give out about 0.5W and their BPF arrays get hot. You need to be careful as the BPF/PA board is easily "smoked"..I speak from bitter experience. Also with the 735s there are issues with dry joints in and around the antenna connector on the PA board and these can be aggravated by warm running so you might need to get your soldering iron out and remake all the joints. There's quite a bit on the web about this issue.Google is your friend!!! The 706 mk2G is much more accommodating and mine will churn out 15W on WSPR all day at 20% duty cycle and not get too warm. You will need a very good 7 pole chebyshev filter immediately after the rig as the output is a little broadband to say the least at 500, but as these rigs were not designed for down here that is hardly surprising and a good bandpass filter is good practice anyway. As has been stated though, for QRO then the way to go is a transverter or direct transmitter and in the LF today book there are excellent schematics for some serious beasts! Hope this helps With best regards Jim Dr. James Cowburn G7NKS E james.cowburn@virgin.net The information transmitted is intended only for the person to whom it is addressed and may contain confidential and/or privileged material. If you are not the intended recipient, you are hereby notified that you must not read this message. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. Consequently, this email is not intended to be contractually binding. If you received this in error, please contact the sender, return the message as well as its attachments and delete the whole from any computer. _____ From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Daniele Tincani Sent: 26 April 2010 18:23 To: rsgb_lf_group@blacksheep.org Subject: LF: Probably not a new question... Hi LF, among the so-called "communications receivers" (0.1-30MHz, all modes, well-known brands, etc.) in the "< 300 euros" price range (used, of course :-)), which models have good characteristics at LF frequencies? Any recommended models (in the same price range) outside of the "comms receivers" class? Many thanks for your feedbacks. Cheers D. ------=_NextPart_000_0053_01CAE584.43278E30 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Daniele=

 

If you can find= them, then I can recommend the early models of JRC receivers.  I have two NRD515s and a NRD5= 05 and they are all excellent at MF/LF.   I also have an ex marine= comms RX from JRC, the NRD72H and that’s quite good too.

 

Often on Ebay= are the Datong VLF upconverters to 28MHz IF.   These are excellent and I run on= e too.

 

Tx wise I have= used both an IC735 and an IC706 Mk2g on 500 with good effect (CW QSO’s out to 500km and WSJT/WSPR/data out to 1300km).   Both will generate around= 15W of RF at 500khz after the diode snip mods for MARS/CAP/5MHz and 7.2MHZ. &nbs= p; With the IC735 you need to be looking for a later serial number model in th= e black box, the earlier ones in white boxes with green writing don’t li= ke working down at 500 as much and only give out about 0.5W and their BPF= arrays get hot.   You need to be careful as the BPF/PA board is eas= ily “smoked”….I speak from bitter experience.

 

Also with the= 735s there are issues with dry joints in and around the antenna connector on the PA board and the= se can be aggravated by warm running so you might need to get your soldering iro= n out and remake all the joints.   There’s quite a bit on the we= b about this issue…Google is your friend!!!

 

The 706 mk2G is= much more accommodating and mine will churn out 15W on WSPR all day at 20% duty cycle and not= get too warm.    You will need a very good 7 pole chebyshev fil= ter immediately after the rig as the output is a little broadband to say= the least at 500, but as these rigs were not designed for down here that is hard= ly surprising and a good bandpass filter is good practice anyway.

 

As has been sta= ted though, for QRO then the way to go is a transverter or direct transmitter and in the LF tod= ay book there are excellent schematics for some serious beasts!

 

Hope this helps=

 

With best regards=

 

Jim

 

 

Dr. James Cowbu= rn G7NKS

E james.cowburn@virgin.net

 

The information= transmitted is intended only for the person to whom it is addressed and may contain confidential and/or pri= vileged material. If you are not the intended recipient, you are hereby notifi= ed that you must not read this message.
Any review, retransmission, dissemination or other use of, or taking= of any action in reliance upon, this information by persons or entities other= than the intended recipient is prohibited.  Consequently, this email is no= t intended to be contractually binding.
If you received this in error, please contact the sender, return the= message as well as its attachments and delete the whole from any computer.=

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksh= eep.org] On Behalf Of D= aniele Tincani
Sent: 26 April 2010 18:= 23
To: rsgb_lf_group@black= sheep.org
Subject: LF: Probably= not a new question...

 

Hi LF,

among the so-called "communication= s receivers" (0.1-30MHz, all modes, well-known brands, etc.) in the "< 300 euros" price range (used, of course :-)), which models have good characteristics at LF frequencies?

Any recommended models (= in the same price range) outside of the "comms receivers" class?=

Many thanks for your feedbacks.<= /font>

Cheers

D.

 

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