Return-Path: Received: (qmail 17279 invoked from network); 4 Nov 2002 12:52:36 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 4 Nov 2002 12:52:36 -0000 Received: (qmail 9178 invoked by uid 10001); 4 Nov 2002 13:56:36 -0000 Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 4 Nov 2002 13:56:36 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from majordom by post.thorcom.com with local (Exim 4.10) id 188ggN-0004bl-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 04 Nov 2002 12:50:19 +0000 Received: from [193.212.240.200] (helo=virus-out.ttyl.com) by post.thorcom.com with esmtp (Exim 4.10) id 188ggN-0004bX-00 for rsgb_lf_group@blacksheep.org; Mon, 04 Nov 2002 12:50:19 +0000 Received: from [134.47.162.190] by virusscan.ttyl.com with ESMTP for rsgb_lf_group@blacksheep.org; Mon, 4 Nov 2002 13:49:45 +0100 Received: from tns-fbu-22-214.corp.telenor.no ([134.47.162.92]) by tns-fbu-22-209.corp.telenor.no with Microsoft SMTPSVC(5.0.2195.4453); Mon, 4 Nov 2002 13:49:45 +0100 Received: from tns-fbu-22-213.corp.telenor.no ([134.47.162.191]) by tns-fbu-22-214.corp.telenor.no with Microsoft SMTPSVC(5.0.2195.4453); Mon, 4 Nov 2002 13:49:44 +0100 Received: from TNS-FBU-2E-003.corp.telenor.no ([134.47.164.201]) by tns-fbu-22-213.corp.telenor.no with Microsoft SMTPSVC(5.0.2195.4453); Mon, 4 Nov 2002 13:49:45 +0100 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 content-class: urn:content-classes:message MIME-Version: 1.0 Date: Mon, 4 Nov 2002 13:49:44 +0100 Message-ID: <2D280BB697C7EE4C979C5C89925418EF368F39@TNS-FBU-2E-003.corp.telenor.no> Thread-Topic: Feeding an inverted L-antenna Thread-Index: AcKDihGeDCGhbQZ7STWhOfFKsIuNvwAdmWIQ From: jan-martin.noding@telenor.com To: rsgb_lf_group@blacksheep.org X-OriginalArrivalTime: 04 Nov 2002 12:49:45.0146 (UTC) FILETIME=[A6B3C1A0:01C28400] Content-Type: text/html; charset=windows-1252 Subject: LF: VS: Feeding an inverted L-antenna X-Spam-Status: No, hits=2.4 required=5.0tests=GAPPY_TEXT,HTML_FONT_COLOR_RED,NO_REAL_NAME, SPAM_PHRASE_00_01version=2.42 X-Spam-Level: ** Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Content-transfer-encoding: 8bit

Wonder why seems to be a habit use a series coil to tune out the capacitance of the 136kHz aerial, instead of more normal sort of matching - using T- or L-network

Below is shown some impedance for a thought antenna (had to enter some radial length for the program to work) using ENDFEED.exe provided by G4FGQ

H. Height, metres ..   10.0       N. Number of buried radial wires .      2
L. Length, metres .. 150.0       R. Length of radials, metres .....   50.0
W. Wire dia, mm ....   2.00       D. Diameter of radial wires, mm ..    1.0
F. Frequency Kilo-Hz    136       S. Strap length to radials, metres    3.0
G. Ground characteristics:-   Average soil:    R = 100, K = 12
H+L+S = 0.074 wavelengths.
                                   R ohms      jX ohms     Tune out jX with
FEEDPOINT INPUT IMPEDANCE:          18.9      -1096.1     1282.7 micro-Henrys
-------------------------------------------------------------------------------
                             <-- Transcvr      Shunt L      Antenna -->
T-NETWORK L & C values:           142 pF    3666.6 uH       295 pF
-------------------------------------------------------------------------------
                             <-- Transcvr     Series X      Antenna -->
L-NETWORK L & C values:                     2086.4 uH    3328.4 uH
Alternative L & C values:                      656 pF     794.7 uH
-------------------------------------------------------------------------------
LOSS in T-match coil   25.4 % of Tx Pwr      GROUND ELECTRODE SYSTEM, INPUT Z
in antenna conductor    3.3 % .. .. ..             DC Resistance    2.9 ohms
in soil in vicinity   42.6 % .. .. ..             RF Resistance    7.2   ..
in system of radials   28.6 % .. .. ..             RF Reactance     7.0   ..
-------------------------------------------------------------------------------
Overall power radiating efficiency ..   0.05 percent
Overall loss relative to ideal system   33.1 decibels or 5.5 'S-points'

Select H,L,W,F,N,R,D,S,G to change data, B(egin again) or Q(uit program)

you find the program on the link below

>========================
>Free Radio Design Software
>Go to http://www.g4fgq.com
>========================

73,

Jan_Martin
LA8AK (in JO38XC

http://www.laud.no/la6nca/la8ak/
NOTE: Because of heavy spamming now applying eremove.exe, please avoid odd titles!