Return-Path: Received: from mtain-db10.r1000.mx.aol.com (mtain-db10.r1000.mx.aol.com [172.29.64.94]) by air-dc03.mail.aol.com (v127_r1.1) with ESMTP id MAILINDC032-86274bafae1e14b; Sun, 28 Mar 2010 15:29:34 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-db10.r1000.mx.aol.com (Internet Inbound) with ESMTP id 85F243800008C; Sun, 28 Mar 2010 15:29:32 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Nvy9k-0005SL-BM for rs_out_1@blacksheep.org; Sun, 28 Mar 2010 20:28:20 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Nvy9j-0005SC-Q6 for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 20:28:19 +0100 Received: from smtp-out26.alice.it ([85.33.2.26]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Nvy9e-0001SQ-Km for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 20:28:19 +0100 Received: from fbcmmo06.fbc.local ([192.168.184.137]) by smtp-out26.alice.it with Microsoft SMTPSVC(6.0.3790.3959); Sun, 28 Mar 2010 21:28:06 +0200 Received: from FBCMCL01B02.fbc.local ([192.168.69.83]) by fbcmmo06.fbc.local with Microsoft SMTPSVC(6.0.3790.3959); Sun, 28 Mar 2010 21:27:51 +0200 Received: from PCCasa ([87.1.202.252]) by FBCMCL01B02.fbc.local with Microsoft SMTPSVC(6.0.3790.3959); Sun, 28 Mar 2010 21:27:51 +0200 Message-ID: From: "Daniele Tincani" To: References: <71A8DF2CFC0B4036B2664789F2AC98E0@PCCasa> <021b01caceaa$4c358ae0$0201a8c0@Clemens04> In-Reply-To: <021b01caceaa$4c358ae0$0201a8c0@Clemens04> Date: Sun, 28 Mar 2010 21:27:42 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18005 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18005 X-OriginalArrivalTime: 28 Mar 2010 19:27:51.0208 (UTC) FILETIME=[C1A65280:01CACEAC] X-Spam-Score: 1.3 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RCVD_IN_BL_SPAMCOP_NET=1.332 Subject: LF: Re: Re: Balun for tuned loop antenna Content-Type: multipart/alternative; boundary="----=_NextPart_000_0016_01CACEBD.800CE530" 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_MESSAGE, MISSING_OUTLOOK_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-sid: 3039ac1d405e4bafae1c1482 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0016_01CACEBD.800CE530 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Man thanks to Clemens DL4RAJ for his very prompt and helpful reply to= my inquiry. Best 73's Daniele ----- Original Message -----=20 From: Clemens Paul=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, March 28, 2010 9:10 PM Subject: LF: Re: Balun for tuned loop antenna Hi Daniele, according to your description your magnetic loop has an inductively= coupled secondary coil, the pickup coil as you call it, which presumably performs a step-dow= n transformation of around 10:1. Therefore -because of the inductive coupling -=20 you can operate unbalanced on the secondary,i.e. rx side ,without di= sturbing the receiving loop's balance itself. As to mismatch losses you need not worry at all. If the rx had 50 Ohm and the antenna output 1000 Ohm you would just= loose 7,4dB, with 2500 Ohm it would be 8,3dB. If your rx had say 10 kOhm and the antenna 500Ohm you would loose ag= ain 7,4dB. This is of *any* importance for SNR on MW/LW because of the high at= msopheric noise. Probably your low cost RX even will benefit from this small signal= attenuation in terms of less overloading. 73 Clemens DL4RAJ ----- Original Message -----=20 From: Daniele Tincani=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, March 28, 2010 8:08 PM Subject: LF: Balun for tuned loop antenna Hi all, I'm new to the LF and just starting to play with an homebrew tuned= magloop and my small portable (Tecsun PL-600). I managed to enable (by means of the soldering iron :-)) the exter= nal antenna jack also for MF and LF on PL-600 (normally it only works= in HF). Now I can connect the pick-up turn of my magloop directly to= the radio but I know it would be better to try to keep it balanced by= means of a balun. Here my problem: magloop simulation (with rjeloop3.= exe) tells the antenna has an impedance of between 500 and 2500 ohms= (on the frequencies it covers, from 280KHz up to 1000KHz). On the oth= er hand, I don't think the receiver have a 50ohm input. In fact, it is= designed typically for HF random wires and has a JFET input buffer st= age that should ensure an high impedance. Given these conditions, does= it still make sense to build a balun? If yes, how could it be designe= d in terms of number of turns (primary side and secondary side), etc.? Many thanks for any feedback. Reg's Daniele ----------------------------------------------------------------------= ------ Eingehende eMail ist virenfrei. Von AVG =FCberpr=FCft - www.avg.de=20 Version: 9.0.791 / Virendatenbank: 271.1.1/2775 - Ausgabedatum: 03= /28/10 08:32:00=20 ----------------------------------------------------------------------= -------- Nessun virus nel messaggio in arrivo. Controllato da AVG - www.avg.com=20 Versione: 9.0.791 / Database dei virus: 271.1.1/2774 - Data di rila= scio: 03/27/10 21:32:00 ------=_NextPart_000_0016_01CACEBD.800CE530 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Man thanks to Clemens DL4RAJ for his= very prompt=20 and helpful reply to my inquiry.
Best 73's
Daniele
----- Original Message -----
Sent: Sunday, March 28, 2010= 9:10=20 PM
Subject: LF: Re: Balun for tu= ned loop=20 antenna

Hi Daniele,
 
according to your description your= magnetic loop=20 has an inductively coupled secondary coil,
the pickup coil as you call it,=20 which presumably performs a step-down transformation
of around 10:1.
Therefore -because of the inductive= coupling -=20
you can operate unbalanced on= the=20 secondary,i.e. rx side ,without disturbing the receiving=20 loop's
balance itself.
As to mismatch losses you need not= worry at=20 all.
If the rx had 50 Ohm and the antenn= a output 1000=20 Ohm you would just loose=20 7,4dB,
with 2500 Ohm it would=20 be 8,3dB.
If your rx had say 10 kOhm and the= antenna 500Ohm=20 you would loose again 7,4dB.
This is of *any* importance for&nbs= p; SNR on=20 MW/LW because of the high atmsopheric noise.
Probably your low cost RX even will= benefit from=20 this small signal attenuation in terms of less
overloading.
 
73
Clemens
DL4RAJ
----- Original Message -----
From:=20 Daniele Tincani
Sent: Sunday, March 28, 201= 0 8:08=20 PM
Subject: LF: Balun for tune= d loop=20 antenna

Hi all,
I'm new to the LF and just starti= ng to play=20 with an homebrew tuned magloop and my small portable (Tecsun=20 PL-600).
I managed to enable (by means of= the soldering=20 iron :-)) the external antenna jack also for MF and LF on PL-600= (normally=20 it only works in HF). Now I can connect the pick-up turn of my mag= loop=20 directly to the radio but I know it would be better to try to keep= it=20 balanced by means of a balun. Here my problem: magloop simula= tion (with=20 rjeloop3.exe) tells the antenna has an impedance of betw= een 500=20 and 2500 ohms (on the frequencies it covers, from 280KHz up to 100= 0KHz). On=20 the other hand, I don't think the receiver have a 50ohm input. In= fact, it=20 is designed typically for HF random wires and has a JFET input buf= fer stage=20 that should ensure an high impedance. Given these conditions, does= it still=20 make sense to build a balun? If yes, how could it be designed in= terms of=20 number of turns (primary side and secondary side), etc.?
Many thanks for any feedback.
Reg's
Daniele
 


Eingehende eMail ist virenfrei.
Von AVG =FCberpr=FCf= t - www.avg.de=20
Version: 9.0.791 / Virendatenbank: 271.1.1/2775 - Ausgabedatum= : 03/28/10=20 08:32:00


Nessun virus nel messaggio in arrivo.
Controllato da= AVG -=20 www.avg.com
Versione: 9.0.791 / Database dei virus: 271.1.1/2774= - =20 Data di rilascio: 03/27/10 21:32:00
------=_NextPart_000_0016_01CACEBD.800CE530--