Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-da01.r1000.mx.aol.com (Internet Inbound) with ESMTP id DB0C33800009F; Wed, 28 Mar 2012 16:14:03 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SCzEq-0006le-Qs for rs_out_1@blacksheep.org; Wed, 28 Mar 2012 21:13:00 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SCzEq-0006lV-0R for rsgb_lf_group@blacksheep.org; Wed, 28 Mar 2012 21:13:00 +0100 Received: from mail-wi0-f181.google.com ([209.85.212.181]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1SCzEn-0007j0-EB for rsgb_lf_group@blacksheep.org; Wed, 28 Mar 2012 21:12:59 +0100 Received: by wibhr17 with SMTP id hr17so1237245wib.10 for ; Wed, 28 Mar 2012 13:12:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=fMWm/V8esXYQHPpAX5cFSvjMZgEpWguSo7caH/Wx4uw=; b=QG/dG+vUxxy/9YZjD996UlQByNjPzb/UGbSb0goNGq24MEKXoqM++IKCgt5xgDUYxZ qb+tr/9ee8GKbhB1lEPAWyZiHdkX8wykGHAzdtuarVlYCK+jmfyzzc/FhrwtP7gtAeSA p8CxSGvj+TwmeuMY/bECn4i9EQoC4LFUJy3Se19cmpu1Nx8qs7jg5lIjluDj9lcJj4Um DB9OF9k1ugWU7m24xgGxNknrdIvcTHeZk7LRCXoUhSiCGqE3Ud9HzSkB9jWxGMS3yObv b+zmaIlQqqs+yM65YFpviev+IkWRTtrHFfhMEb5j+XkIYGkhuVd87eSOIDgONRTmZYVl 72ew== MIME-Version: 1.0 Received: by 10.180.88.67 with SMTP id be3mr1019978wib.20.1332965571239; Wed, 28 Mar 2012 13:12:51 -0700 (PDT) Received: by 10.180.101.65 with HTTP; Wed, 28 Mar 2012 13:12:51 -0700 (PDT) In-Reply-To: <20120328144112.Q58F2.191646.imail@eastrmwml302> References: <1332955568.73564.YahooMailNeo@web160601.mail.bf1.yahoo.com> <20120328144112.Q58F2.191646.imail@eastrmwml302> Date: Wed, 28 Mar 2012 21:12:51 +0100 Message-ID: From: Roger Lapthorn To: sub9khz@yahoogroups.com, rsgb_lf_group@blacksheep.org X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TINY_FONT=1.425 Subject: LF: Re: [sub9khz] E-field probe performance Content-Type: multipart/alternative; boundary=f46d044481475f1f6904bc533bdf X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40, HTML_FONTCOLOR_UNSAFE,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-SCOLL-SCORE: 1:2:477276000:93952408 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d291.1 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1d40494f73710b118a X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --f46d044481475f1f6904bc533bdf Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Various preamps and E-field probe schematics at https://sites.google.com/site/sub9khz/antennas . If you know of others suitable for VLF use tell me and I'll add them. I'm a little puzzled by some of the responses, particularly as both PA0RDT and DK7FC designs are E-field probes then surely a "same height, same ground and PSU conditions" test should be possible with a resulting figure possible for like-for-like noise floor, sensitivity (S/N of Alpha beacons, VLF MSK signals), and by looking for the intensity of the intermod line at 9kHz from broadcast signals in Europe an indication of dynamic range? Has no-one done this test at VLF? If not, it looks like I shall have to do it and "suck it and see". 73s Roger G3XBM On 28 March 2012 19:41, wrote: > ** > > > Hi Jim , > > Where did you locate a schematic of the DK7FC , E-probe ? I would like to > have a look at it . > > Thanks. > > Best 73 , > > Charlie , W5COV > > > ---- James Wagner wrote: > > From just looking at the schematics, the PA0RDT design is much higher > bandwidth (pushing 10MHz) than the DK7FC design. That places much higher > demand on linearity in the presence of strong in-band signals. How that > plays out in real life will depend on circumstances. For example, there i= s > a 5KW (significantly higher ERP) AM station at 550KHz less than 10 miles > from my QTH. I don't know that it would cause a problem, but I would be > careful. There is also a low-power NDB at 225KHz about 15 miles from my > QTH. This one should not cause a problem but both are probably in-band fo= r > both receivers. > > > > I do note that DK7FC design has limiting diodes at the input of the > receiver. This MIGHT well cause a problem with strong-signal > intermodulation. Again, it would depend on local circumstances. > > > > Jim Wagner > > KA7EHK CN84km > > > > > > ________________________________ > > From: Roger Lapthorn > > To: rsgb_lf_group@blacksheep.org; sub9khz@yahoogroups.com > > Sent: Wednesday, March 28, 2012 5:43 AM > > Subject: [sub9khz] E-field probe performance > > > > > > > > Several of the VLF grabbers are now using Stefan DK7FC's E-field probe > (Tel > > Aviv, Ipswich, Iceland etc). I'm wondering if anyone has done a straigh= t > > comparison against the PA0RDT design and measured which is better in > terms > > of sensitivity and dynamic range? > > > > 73s > > Roger G3XBM > > > > -- > > http://qss2.blogspot.com/ > > http://g3xbm-qrp.blogspot.com/ > > http://www.g3xbm.co.uk > > https://sites.google.com/site/sub9khz/ > > > > [Non-text portions of this message have been removed] > > > > > > > > > > [Non-text portions of this message have been removed] > > > > __._,_.___ > Reply to sender| Reply > to group| Reply > via web post| Start > a New Topic > Messages in this topic( > 4) > Recent Activity: > > - New Members > 1 > > Visit Your Group > [image: Yahoo! Groups] > Switch to: Text-Only, > Daily Digest=95 > Unsubscribe = =95 Terms > of Use > . > > __,_._,___ > --=20 http://qss2.blogspot.com/ http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk https://sites.google.com/site/sub9khz/ --f46d044481475f1f6904bc533bdf Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Various preamps and E-field probe schematics at https://sites.google.com/site/sub9khz/anten= nas . If you know of others suitable for VLF use tell me and I'll a= dd them.

I'm a little puzzled by some of the responses, particularly as both= PA0RDT and DK7FC designs are E-field probes then surely a "same heigh= t, same ground and PSU conditions" test should be possible with a resu= lting figure possible for like-for-like noise floor, sensitivity (S/N of Al= pha beacons, VLF MSK signals), and by looking for the intensity of the inte= rmod line at 9kHz from broadcast signals in Europe an indication of dynamic= range? Has no-one done this test at VLF? If not, it looks like I shall hav= e to do it and "suck it and see".

73s
Roger G3XBM


On 28 March 20= 12 19:41, <cvest@cox= .net> wrote:
=A0
=20 =20

Hi Jim ,

Where did you locate a schematic of the DK7FC , E-probe ? I would like to h= ave a look at it .

Thanks.

Best 73 ,

Charlie , W5COV



---- James Wagner <ka7ehk@yahoo.com> wrote:
> From just looking at the schematics, the PA0RDT design is much higher = bandwidth (pushing 10MHz) than the DK7FC design. That places much higher de= mand on linearity in the presence of strong in-band signals. How that plays= out in real life will depend on circumstances. For example, there is a 5KW= (significantly higher ERP) AM station at 550KHz less than 10 miles from my= QTH. I don't know that it would cause a problem, but I would be carefu= l. There is also a low-power NDB at 225KHz about 15 miles from my QTH. This= one should not cause a problem but both are probably in-band for both rece= ivers.
>
> I do note that DK7FC design has limiting diodes at the input of the re= ceiver. This MIGHT well cause a problem with strong-signal intermodulation.= Again, it would depend on local circumstances.
>
> Jim Wagner
> KA7EHK CN84km
>
>
> ________________________________
> From: Roger Lapthorn <rogerlapthorn@gmail.com>
> To: rsgb_lf_group@blacksheep.org; sub9khz@yahoogroups.com
> Sent: Wednesday, March 28, 2012 5:43 AM
> Subject: [sub9khz] E-field probe performance
>
>
> =A0
> Several of the VLF grabbers are now using Stefan DK7FC's E-field p= robe (Tel
> Aviv, Ipswich, Iceland etc). I'm wondering if anyone has done a s= traight
> comparison against the PA0RDT design and measured which is better in t= erms
> of sensitivity and dynamic range?
>
> 73s
> Roger G3XBM
>
> --
> http://qss2.bl= ogspot.com/
> http://g3= xbm-qrp.blogspot.com/
> http://www.g3xbm.= co.uk
> h= ttps://sites.google.com/site/sub9khz/
>
> [Non-text portions of this message have been removed]
>
>
>
>
> [Non-text portions of this message have been removed]
>

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= Recent Activity: =20
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--
http://qss2.blogspot.com/
http://g3xb= m-qrp.blogspot.com/
http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/

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