To: rsgb_lf_group@blacksheep.org
MIME-Version: 1.0
From: Markus Vester <markusvester@aol.com>
Message-Id: <8CE1F480AFAA39A-BE4-3E91@webmail-d146.sysops.aol.com>
Date: Tue, 2 Aug 2011 12:26:19 -0400 (EDT)
X-AOL-SCOLL-URL_COUNT: 0  
X-Spam-Score: 0.0 (/)
X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,UNPARSEABLE_RELAY=0.001
Subject: LF: Fieldstrength and radiated power
Content-Type: multipart/alternative; 
 boundary="--------MB_8CE1F480B10100C_BE4_B987_webmail-d146.sysops.aol.com"
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com
X-Spam-Level: 
X-Spam-Status: No, hits=0.1 required=5.0 tests=HTML_FONTCOLOR_UNKNOWN,
	HTML_MESSAGE 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-SCOLL-SCORE: 0:2:428207904:93952408  
X-AOL-SCOLL-URL_COUNT: 0  
x-aol-sid: 3039ac1d60564e38258a3aaf
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


This is a multi-part message in MIME format.
----------MB_8CE1F480B10100C_BE4_B987_webmail-d146.sysops.aol.com
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; charset="us-ascii"


Dear LF,

to support estimates of radiated power, I have added a fieldstrength readou=
t on my LF grabber=20

 http://www.alice-dsl.net/df6nm/grabber/Grabber.htm

It simply displays the peak frequency and amplitude within the QRSS subband=
 at the time of the capture (ie. every five minutes). Due to different cali=
bration issues, the readout will be accurate only to within about 3 dB. The=
re may also be considerable day-to-day variation, for example from switchin=
g between different receive antennas.

In the region of groundwave dominance (up to 400 km daytime, 200 km in dark=
ness), radiated power in dBm or milliwatts can be roughly estimated based o=
n distance R using

 EMRP[dBm] =3D 20 log E[uV/m] + 20 log R[km] + 0.02 R[km] - 49.5
 EMRP[mW] =3D 10^(EMRP[dBm]/10)

To convert to halfwave-dipole ERP or EIRP, you would have to apply the usua=
l factor of 1.83 or 3.

Hope this may be useful...

Best 73,
Markus (DF6NM)





----------MB_8CE1F480B10100C_BE4_B987_webmail-d146.sysops.aol.com
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html; charset="us-ascii"

<font color=3D'black' size=3D'2' face=3D'arial'>
<div>Dear LF,</div>


<div>&nbsp;</div>


<div>to support estimates of radiated power, I have added a fieldstrength r=
eadout on my LF grabber </div>


<div>&nbsp;</div>


<div>&nbsp;<A href=3D"http://www.alice-dsl.net/df6nm/grabber/Grabber.htm">h=
ttp://www.alice-dsl.net/df6nm/grabber/Grabber.htm</A></div>


<div>&nbsp;</div>


<div>It simply displays the peak frequency and amplitude within the QRSS su=
bband at the time of the capture (ie. every five minutes). Due to different=
 calibration issues, the readout will be accurate only to within about 3 dB=
. There may also be considerable day-to-day variation, for example from swi=
tching between different receive antennas.</div>


<div>&nbsp;</div>


<div>In the region of groundwave dominance (up to 400 km daytime, 200 km in=
 darkness), radiated power in dBm or milliwatts can be roughly estimated ba=
sed on distance R using</div>


<div>&nbsp;</div>


<div>&nbsp;EMRP[dBm] =3D 20 log E[uV/m] + 20 log R[km] + 0.02 R[km] - 49.5<=
/div>


<div>&nbsp;EMRP[mW] =3D 10^(EMRP[dBm]/10)</div>


<div>&nbsp;</div>


<div>To convert to halfwave-dipole ERP or EIRP, you would have to apply the=
 usual factor of 1.83 or 3.</div>


<div>&nbsp;</div>


<div>Hope this may be useful...</div>


<div>&nbsp;</div>


<div>Best 73,<br>
Markus (DF6NM)<br>
<br>
<br>
</div>


<div style=3D"CLEAR: both"></div>
</font>
----------MB_8CE1F480B10100C_BE4_B987_webmail-d146.sysops.aol.com--