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Content preview: Hello Daniele, some months ago I made a broadbanded ferriterod to cope with heavy qrm on the 80 and 160m band.The ferite comes from a submarine and is specified 10KHz to 4 MHZ with a symmetrical feedingcable to a ELK675 or other receiver without a preamp.Since I don't have such a receiver I made a balanced two stage amp with 4x BD139 grounded base.The antenna copes good with the QRM on 80 and 160,it also performs very well on the MW broadcastband.In the range 200-500KHz it is sometimes better than the E-probe,below 200KHz the E-probe wins.IM is no problem but maby the noise of the amp is to high below 200KHz. The ferriterod is about750X100mm! I don't think the 12AU7 is a good choice for a low inputimpedance amp...Zinput 2X BD139 is about 3 Ohm. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [194.134.42.51 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 54c274b8b0f8da777e8f702c98fe24ad Subject: LF: RE: Ferrite broadband (LF-MF) antenna? Content-Type: multipart/alternative; boundary="----=_NextPart_000_0044_01CD5092.BF6B73F0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.1 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_30_40, HTML_FONTCOLOR_BLUE,HTML_MESSAGE,NO_REAL_NAME 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: 0:2:360805504:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d408e4fe47f1c771d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_0044_01CD5092.BF6B73F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hello Daniele, some months ago I made a broadbanded ferriterod to cope with heavy qrm on the 80 and 160m band.The ferite comes from a submarine and is specified 10KHz to 4 MHZ with a symmetrical feedingcable to a ELK675 or other receiver without a preamp.Since I don't have such a receiver I made a balanced two stage amp with 4x BD139 grounded base.The antenna copes good with the QRM on 80 and 160,it also performs very well on the MW broadcastband.In the range 200-500KHz it is sometimes better than the E-probe,below 200KHz the E-probe wins.IM is no problem but maby the noise of the amp is to high below 200KHz. The ferriterod is about750X100mm! I don't think the 12AU7 is a good choice for a low inputimpedance amp...Zinput 2X BD139 is about 3 Ohm. 73 GL Victor PA3FNY -----Oorspronkelijk bericht----- Van: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Daniele Tincani Verzonden: vrijdag 22 juni 2012 9:42 Aan: rsgb_lf_group@blacksheep.org Onderwerp: LF: Ferrite broadband (LF-MF) antenna? Hello LF, I apologize to you all for resuming a topic that was already largely debated here. I have seven of those quite known russian surplus ferrite rods (20cm x 1cm) and - just for my fun - I'm planning to spend some time in building an LF-MF antenna with them. I would like to obtain a broadband (untuned) antenna, ideally VLF-LF and/or LF-MF, suitable for outdoor installation, so what I would appreciate some suggestions about is the required low-impedance amplifier, similar to those used in air-core broadband loops, if it does make sense of course. Any ideas? I found an unused 12AU7 in my drawer, could it be effectively chosen as the active device (low voltage) for such amplifier? Thank you for any feedback 73 Daniele IZ5WWB ------=_NextPart_000_0044_01CD5092.BF6B73F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello=20 Daniele,
 
some=20 months ago I made a broadbanded ferriterod to cope with heavy qrm on the = 80 and=20 160m band.The ferite comes from a submarine and is specified 10KHz to 4 = MHZ with=20 a symmetrical feedingcable to a ELK675 or other receiver without a = preamp.Since=20 I don't have such a receiver I made a balanced two stage amp with 4x = BD139=20 grounded base.The antenna copes good with the QRM on 80 and 160,it also = performs=20 very well on the MW broadcastband.In the range 200-500KHz it is = sometimes better=20 than the E-probe,below 200KHz the E-probe wins.IM is no problem but maby = the=20 noise of the amp is to high below 200KHz.
The=20 ferriterod is about750X100mm!
I=20 don't think the 12AU7 is a good choice for a low inputimpedance = amp...Zinput 2X=20 BD139 is about 3 Ohm.
 
73
GL
Victor
PA3FNY
 
-----Oorspronkelijk bericht-----
Van:=20 owner-rsgb_lf_group@blacksheep.org=20 [mailto:owner-rsgb_lf_group@blacksheep.org]Namens Daniele=20 Tincani
Verzonden: vrijdag 22 juni 2012 9:42
Aan:=20 rsgb_lf_group@blacksheep.org
Onderwerp: LF: Ferrite = broadband=20 (LF-MF) antenna?

Hello LF,
 
I apologize to you all for resuming a topic that was already = largely=20 debated here. I have seven of those quite known russian surplus = ferrite=20 rods (20cm x 1cm) and - just for my fun - I'm planning to spend = some time=20 in building an LF-MF antenna with them. I would like to obtain=20 a broadband (untuned) antenna, ideally VLF-LF and/or LF-MF, = suitable=20 for outdoor installation, so what I would appreciate some suggestions = about is=20 the required low-impedance amplifier, similar to those used in = air-core=20 broadband loops, if it does make sense of course. Any ideas? I found = an unused=20 12AU7 in my drawer, could it be effectively chosen as = the=20 active device (low voltage) for such amplifier?
Thank you for any feedback
73
Daniele IZ5WWB
 
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