Return-Path: X-Spam-DCC: paranoid 1170; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: * X-Spam-Status: No, score=1.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_MUA_OUTLOOK,HTML_MESSAGE,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u37NQQPm029845 for ; Fri, 8 Apr 2016 01:26:26 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aoJEu-00024P-F7 for rs_out_1@blacksheep.org; Fri, 08 Apr 2016 00:21:28 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aoJEt-00024G-V8 for rsgb_lf_group@blacksheep.org; Fri, 08 Apr 2016 00:21:27 +0100 Received: from rgout0301.bt.lon5.cpcloud.co.uk ([65.20.0.207]) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1aoJEs-00007q-40 for rsgb_lf_group@blacksheep.org; Fri, 08 Apr 2016 00:21:26 +0100 X-OWM-Source-IP: 81.152.77.81 (GB) X-OWM-Env-Sender: alan.melia@btinternet.com X-CTCH-RefID: str=0001.0A090202.5706EB74.007D,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-Junkmail-Premium-Raw: score=40/50,refid=2.7.2:2016.3.31.190617:17:40.733,ip=81.152.77.81,rules=__HAS_MSGID, __SANE_MSGID, MSGID_32HEX_LC, INVALID_MSGID_NO_FQDN, __MSGID_32HEX, __HAS_FROM, __PHISH_FROM2, __FRAUD_WEBMAIL_FROM, __TO_MALFORMED_2, __TO_NO_NAME, __BOUNCE_CHALLENGE_SUBJ, __BOUNCE_NDR_SUBJ_EXEMPT, __MIME_VERSION, __CT, __CTYPE_MULTIPART_ALT, __CTYPE_HAS_BOUNDARY, __CTYPE_MULTIPART, __HAS_X_PRIORITY, __HAS_MSMAIL_PRI, __HAS_X_MAILER, USER_AGENT_OE, __OUTLOOK_MUA_1, __USER_AGENT_MS_GENERIC, __ANY_URI, __FRAUD_BODY_WEBMAIL, __URI_NO_WWW, __FRAUD_MONEY_BIG_COIN_DIG, __SUBJ_ALPHA_NEGATE, SUPERLONG_LINE, __HTML_AHREF_TAG, __HAS_HTML, HTML_NO_HTTP, BODYTEXTP_SIZE_3000_LESS, BODYTEXTH_SIZE_3000_MORE, BODYTEXTH_SIZE_10000_LESS, __MIME_HTML, __TAG_EXISTS_HTML, RDNS_GENERIC_POOLED, __URI_NS, SXL_IP_DYNAMIC[81.77.152.81.fur], HTML_50_70, __FRAUD_MONEY_BIG_COIN, RDNS_SUSP_GENERIC, __FRAUD_WEBMAIL, __PHISH_FROM, __OUTLOOK_MUA, RDNS_SUSP, FORGED_MUA_OUTLOOK, NO_URI_HTTPS X-CTCH-Spam: Unknown Received: from gnat (81.152.77.81) by rgout03.bt.lon5.cpcloud.co.uk (8.6.122.06) (authenticated as alan.melia@btinternet.com) id 56F6915D0161CA16 for rsgb_lf_group@blacksheep.org; Fri, 8 Apr 2016 00:21:24 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1460071286; bh=AuI6C+BzIzcCUw6ZP5UBirDczN+vgwOH/GZmnIxawjo=; h=Message-ID:From:To:References:Subject:Date:MIME-Version:X-Mailer; b=rI/+DLFVOhYCdQhQNdxTY9NCoFWeLtHy/TRCigzscIliLjESY4jDBEejJz8muSGtTjp81IcBx+1ANi3syScO0xXQTOmZwfzyeAuFXHfme6Kney9xTK7Ou9XicuatFWf9tu9d9hN0yD/1xtgsmKIP4woLkmX8Tp1dTH6yQBgA5ns= Message-ID: From: "Alan Melia" To: References: <1840555212.2044542.1460066335241.JavaMail.yahoo.ref@mail.yahoo.com>,<1840555212.2044542.1460066335241.JavaMail.yahoo@mail.yahoo.com> <7E7DFBB4D102A04DB5ADC88D66628A4A444EBB97@ICTS-S-MBX1.luna.kuleuven.be> Date: Fri, 8 Apr 2016 00:21:34 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-Scan-Signature: 14e68a9cb6dee915a96310ea9bf261c5 Subject: LF: Re: RE: Field Strength Measurements Content-Type: multipart/alternative; boundary="----=_NextPart_000_01EB_01D1912C.9B59D7C0" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7611 This is a multi-part message in MIME format. ------=_NextPart_000_01EB_01D1912C.9B59D7C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Chris two other points 1. How far from the aerial are you taking the measurement .....you need = to be at least 300 to 500 metres away 2 Because of ground loss problems even the best (fully in the clear) = amateur short aerials measure around 5 to 6 dB low.(that is a 136kHz = observation.) Often a better reading is taken say a mile away on = slightly elevated ground to the aerial site. Jim Moritz did tests in a = field adjacent to the Puckeridge Decca mast, with a 10m high inverted L. = Alan G3NYK ----- Original Message -----=20 From: Rik Strobbe=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, April 07, 2016 11:24 PM Subject: LF: RE: Field Strength Measurements Hello Chris, (1) will give you the EMRP (Effective Monopole Radiated Power) (2) will give you the EIRP (Effective Isotropic Radiated Power) The formula P =3D 0.0203252(Ed)^2 will give you the ERP (Effective = Radiated Power) 73, Rik ON7YD - OR7T -------------------------------------------------------------------------= ----- Van: owner-rsgb_lf_group@blacksheep.org = [owner-rsgb_lf_group@blacksheep.org] namens Chris Osborn = [g3xiz@yahoo.co.uk] Verzonden: donderdag 7 april 2016 23:58 Aan: LF Group Onderwerp: LF: Field Strength Measurements LF,=20 I've recently resurrected my old RF field strength meter as designed = by PA0SE and published in the LF Experimenters' Handbook. I've modifed it to measure signals in the MF band and have calibrated = it with a home made Helmholtz coil arrangement. This question may have been raised before but PA0SE gives the formula = for deriving the transmitter power as P =3D 0.0111 (Ed)^2 . . . (1) where E is the electrical field strength and d the distance I've read in other places that the power from an isotropic radiator is P =3D (Ed)^2 / 30=20 i.e. 0.0333 (Ed)^2 . . . . (2) My calculated radiated power seems rather low so I'm wondering whether = I should be using formula (2) Any clarification would be most welcome. 73 Chris G3XIZ ------=_NextPart_000_01EB_01D1912C.9B59D7C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Chris two other points
1.  How far from the aerial are = you taking the=20 measurement .....you need to be at least 300 to 500 metres = away
2   Because of ground loss = problems even=20 the best (fully in the clear) amateur short aerials measure around = 5 to 6=20 dB low.(that is a 136kHz observation.) Often a better reading is taken = say a=20 mile away on slightly elevated ground to the aerial site. Jim Moritz did = tests=20 in a field adjacent to the Puckeridge Decca mast, with a 10m high = inverted L.=20
 
Alan
G3NYK
 
 
----- Original Message -----
From:=20 Rik Strobbe
Sent: Thursday, April 07, 2016 = 11:24=20 PM
Subject: LF: RE: Field Strength = Measurements

Hello Chris,

 

(1) will give you the EMRP (Effective Monopole Radiated Power)

(2) will give you the EIRP (Effective Isotropic Radiated Power)

The formula P =3D 0.0203252(Ed)^2 will give you the ERP (Effective = Radiated=20 Power)

 

73, Rik  ON7YD - OR7T

 

Van: owner-rsgb_lf_group@bl= acksheep.org=20 [owner-rsgb_lf_group@blacksheep.org] namens Chris Osborn=20 [g3xiz@yahoo.co.uk]
Verzonden: donderdag 7 april 2016=20 23:58
Aan: LF Group
Onderwerp: LF: Field Strength=20 Measurements

LF,

I've recently = resurrected my old=20 RF field strength meter as designed by PA0SE and published in the LF=20 Experimenters' Handbook.
I've modifed it to = measure=20 signals in the MF band and have calibrated it with a home made = Helmholtz coil=20 arrangement.

This question may have = been=20 raised before but PA0SE gives the formula for deriving the transmitter = power=20 as

P =3D 0.0111 = (Ed)^2  . .=20 .   (1)

where E is the = electrical field=20 strength and d the distance

I've read in other = places that=20 the power from an isotropic radiator is

P =3D (Ed)^2 / 30 =

i.e.  0.0333 = (Ed)^2  .=20 . . . (2)

My calculated radiated = power=20 seems rather low so I'm wondering whether I should be using formula = (2)

Any clarification would = be most=20 welcome.

73
Chris G3XIZ







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