Return-Path: Received: (qmail 5431 invoked from network); 11 Nov 2003 16:24:33 -0000 Received: from unknown (HELO netmail02.services.quay.plus.net) (212.159.14.221) by mailstore with SMTP; 11 Nov 2003 16:24:33 -0000 Received: (qmail 521 invoked by uid 10001); 11 Nov 2003 16:24:32 -0000 X-Priority: 3 X-MSMail-Priority: Normal X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.20) by netmail02.services.quay.plus.net with SMTP; 11 Nov 2003 16:23:11 -0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AJbGm-0008Kc-Ry for rsgb_lf_group-outgoing@blacksheep.org; Tue, 11 Nov 2003 16:21:32 +0000 Received: from [217.72.192.165] (helo=mailgate5.cinetic.de) by post.thorcom.com with esmtp (Exim 4.14) id 1AJbGm-0008KS-0k for rsgb_lf_group@blacksheep.org; Tue, 11 Nov 2003 16:21:32 +0000 Received: from web.de (fmomail01.dlan.cinetic.de [172.20.1.45]) by mailgate5.cinetic.de (8.11.6p2/8.11.2/SuSE Linux 8.11.0-0.4) with SMTP id hABGL1Q21253 for rsgb_lf_group@blacksheep.org; Tue, 11 Nov 2003 17:21:01 +0100 Date: Tue, 11 Nov 2003 17:21:01 +0100 Message-ID: <200311111621.hABGL1Q21253@mailgate5.cinetic.de> MIME-Version: 1.0 Organization: http://freemail.web.de/ From: "Hans-Albrecht Haffa" To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Dummy-Load on LW Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.7 required=5.0 tests=HTML_20_30,HTML_FONT_BIG,HTML_MESSAGE,MIME_HTML_ONLY autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Rating: 1

Dear Lowfers,

for my experiments I use commercial dummy loads, like my Rohde & Schwarz RD1/60, oil filled, 1 kW /60 Ohm with monitor output attenuation of about 40 dB with Dezifix-connectors (the sexless Bajonnet ones ...). A dry portable 150 W-Version I have too.

I definitely do not recommend homebrew constructions at these high power ratings. The danger of fire is to big, and resistors of adequate power rating are expensive too. I bought my collecton of attenuators at Ham Radio fair at modest prizes. 60 Ohm equipment is not what hams like, but Power error is minimal when the attenuator output is terminated by a 50 Ohm-Power-Meter, or is not terminated at all (after an attenuation of 30ddbB or more ).

An other possible equipment is the noisy test load KAM, "Kunstantenne mit Meßausgang" from late German Democratic Republic, designed for the transmitter KSG1300.

55, Hans-Albrecht

DK 8 ND

rsgb_lf_group@blacksheep.org schrieb am 08.11.03 18:52:32:
>
>
> With all the comments on Loads,,, put them in a container and add mineral
> oil
> would really boost their rating ,, just allow for some venting
>
> Bob K3DJC
>
> On Sat, 8 Nov 2003 01:23:05 +0100 0482183881-0001@t-online.de (jannsen)
> writes:
> > James Moritz schrieb:
> >
> > ...............
> >
> > > Several people have resorted to electric heating elements like
> > > toasters and fan heaters to make satisfactory LF dummy loads.
> >
> > Hi Jim es all,
> >
> > here are two dummy loads in use; one is a bulb 110V/DC500W, Z 35 Ohm
> > on 136kHz
> > (bridge measurement) and the other is made of four hollow ceramic
> > resistors
> > 200 Ohm/60W each, makes 200W only. but blowing air through the
> > resistors
> > (see attachment) makes a lukewarm 300W dummy on 136kHz (0,4uH only).
> >
> > I tried 800W. A peace of paper above the dummy caught fire within 10
> > sec.
> >
> > regards
> > Uwe/dj8wx
> >
> >
> >
>

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