Return-Path: Received: from mtain-dc11.r1000.mx.aol.com (mtain-dc11.r1000.mx.aol.com [172.29.64.139]) by air-mf02.mail.aol.com (v129.4) with ESMTP id MAILINMF023-8bcf4d1bd0462b0; Wed, 29 Dec 2010 19:20:22 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dc11.r1000.mx.aol.com (Internet Inbound) with ESMTP id BFE45380000B6; Wed, 29 Dec 2010 19:20:19 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PY6Em-00005a-0P for rs_out_1@blacksheep.org; Thu, 30 Dec 2010 00:19:24 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PY6El-00005R-1F for rsgb_lf_group@blacksheep.org; Thu, 30 Dec 2010 00:19:23 +0000 Received: from smtp5.freeserve.com ([193.252.22.151] helo=smtp6.freeserve.com) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PY6Ej-0002J7-No for rsgb_lf_group@blacksheep.org; Thu, 30 Dec 2010 00:19:23 +0000 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3531.me.freeserve.com (SMTP Server) with ESMTP id EEF541C00081 for ; Thu, 30 Dec 2010 01:19:15 +0100 (CET) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3531.me.freeserve.com (SMTP Server) with ESMTP id DEC451C00085 for ; Thu, 30 Dec 2010 01:19:15 +0100 (CET) Received: from AGB (unknown [91.110.70.240]) by mwinf3531.me.freeserve.com (SMTP Server) with SMTP id 488C41C00081 for ; Thu, 30 Dec 2010 01:19:13 +0100 (CET) X-ME-UUID: 20101230001913297.488C41C00081@mwinf3531.me.freeserve.com Message-ID: From: "Graham" To: References: <4D1B7B17.2040007@iup.uni-heidelberg.de> In-Reply-To: Date: Thu, 30 Dec 2010 00:19:12 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Antivirus: avast! (VPS 101229-0, 29/12/2010), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: DK7FC's VLF Active Antenna Content-Type: multipart/alternative; boundary="----=_NextPart_000_0016_01CBA7B7.2F5A4550" 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: 3039ac1d408b4d1bd0431f03 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_0016_01CBA7B7.2F5A4550 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable SMT is not that bad ...=20 Pre-heating the board first is a good move ..pre heater ? , well= domestic IRON is a nice size flat plate , tem controlled as wel= l .. synthetics ? cotton may be too hot (no steam of course .. th= at comes later at the testing stage) small butane blow lamp works nicely ..two soldering irons at once= for simple components ... =20 the big chips will go with 1 pass of the iron on each side ...= 1 pass !!=20 sticky solder flux paste .. lots of solder wick .. =20 components will 'suck' down to the board once the solder is melted= at each end ... and as there are no plated holes , physical boa= rd damage is much reduced ..if it all go's wrong , clean the boa= rd up and start again=20 >>> Start practicing now before you're forced to. >>> Lots of old= PC boards and cards about to play with as well , remove and = replace the components - minimal solder is needed as the pad are= a is quite big=20 G .. =20 From: Andy Talbot=20 Sent: Wednesday, December 29, 2010 11:52 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: DK7FC's VLF Active Antenna It won't be long before leaded components become unavailable. Certain= ly the useful modern ones that actually do teh job that's wanted. I'= ve compared availability and prices in the Farnell catalogue recently= (having just got the almost cubic shaped printed version :-) and le= aded components are just more expensive and less available that SMT eq= uivalent. And the bulk ordering quantities available on many of the= m make ordering less than 100 off of some of the more popular ones jus= t a waste of money. =20 Constructors really will have to start getting used to using SMT devic= es are their first choice every time. Start practicing now before you= 're forced to. Andy www.g4jnt.com been using SMT components for preference for something like 15 years= now. =20 2010/12/29 Stefan Sch=E4fer Hi Ken,=20 I have not tested other JFETs so far. Is it just because of the SMD= housing? I don't use a SMD PCB but a "free air" soldering. So if this= is the problem, just solder the FETs legs directly on the next part,= e.g. solder the drain directly on the 390 Ohm resistor. Attached you= find a picture that shows how my current used VLF grabber antenna loo= ks inside. Don't be shocked ;-) If you anyway want an alternative, the J310 or the (2SK170) should= be possible. There are some parameters like the noise and the gain an= d the input capacitance which are affecting the performance but this= is all not so critical on VLF. 73, Stefan/DK7FC Am 29.12.2010 17:58, schrieb Ken:=20 Stefan. Could you please recommend an equivalent to to BF862 which is not= Surface Mount for use in this circuit. 73s Ken M0KHW ------=_NextPart_000_0016_01CBA7B7.2F5A4550 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
SMT is not  that bad ... 
 
Pre-heating the  board  fir= st  is a=20 good  move  ..pre  heater ? , well =20 domestic   IRON is a nice size  flat  plate , tem= controlled=20 as  well  .. synthetics ? cotton may be too  hot= =20    (no steam of course .. that  comes later at the = ;=20 testing  stage)
 
small   butane  blow= lamp works=20 nicely ..two  soldering irons  at once  = for =20 simple  components ... 
the  big  chips will = go =20 with  1 pass  of the  iron  on each side ...1 pass=   !!=20
sticky  solder flux paste ..
lots of  solder wick .. 
 
components will  'suck' down to= the =20 board once the  solder is  melted at each end ... and = as=20 there  are no  plated  holes ,  physical  boa= rd damage=20 is  much  reduced ..if it all  go's  wrong = , clean=20 the  board  up and  start  again
 
>>> Start practicing now before you're forced to.=20 >>>   Lots of  old  PC  boards and&n= bsp;=20 cards  about to  play  with as  well , remove and&= nbsp;=20 replace the  components - minimal  solder  is needed&nb= sp; as=20 the  pad area is quite  big
 
G ..  
 
 

Sent: Wednesday, December 29, 2010 11:52 PM
Subject: Re: LF: DK7FC's VLF Active Antenna

It won't be long before leaded components become unavailable.&nbs= p;=20 Certainly the useful modern ones that actually do teh job that's=20 wanted.   I've compared availability and prices in the Farne= ll=20 catalogue recently (having just got the almost cubic shaped printed ve= rsion=20 :-)   and leaded components are just more expensive and less= available=20 that SMT equivalent.    And the bulk ordering quantitie= s=20 available on many of them make ordering less than 100 off of= some of=20 the more popular ones just a waste of money.   
 
Constructors really will have to start getting used to using SMT= devices=20 are their first choice every time.  Start practicing now before= you're=20 forced to.
 
Andy
 
been using SMT components for preference for something like 15 ye= ars=20 now.
 


 
2010/12/29 Stefan Sch=E4fer &= lt;schaefer@iup.un= i-heidelberg.de>
Hi Ken,

I have not= tested other=20 JFETs so far. Is it just because of the SMD housing? I don't use a= SMD PCB but=20 a "free air" soldering. So if this is the problem, just solder the= FETs legs=20 directly on the next part, e.g. solder the drain directly on the 390= Ohm=20 resistor. Attached you find a picture that shows how my current used= VLF=20 grabber antenna looks inside. Don't be shocked ;-)

If you any= way want=20 an alternative, the J310 or the (2SK170) should be possible.= There are=20 some parameters like the noise and the gain and the input capacitanc= e which=20 are affecting the performance but this is all not so critical on=20 VLF.

73, Stefan/DK7FC



Am 29.12.2010 17:58, sch= rieb Ken:=20
Stefan.
Could you please recommend an equ= ivalent to to=20 BF862 which is not Surface Mount for use in this circuit.
73s
Ken
M0KHW
=



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