Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org)
Message-ID: <20070615001329.6ikxlepiewskckg0@webmail3.kuleuven.be>
Date: Fri, 15 Jun 2007 00:13:29 +0200
From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: rsgb_lf_group@blacksheep.org
References: <001f01c7ae26$3474ab40$c2137ad5@w4o8m9>
	<20070614125512.BD7D431E702@smtps01.kuleuven.be>
	<46718D94.8050303@telia.com>
In-Reply-To: <46718D94.8050303@telia.com>
MIME-Version: 1.0
Content-Disposition: inline
User-Agent: Internet Messaging Program (IMP) H3 (4.1.2)
Subject: Re: LF: M0BMU ERP on 500k
Content-Type: text/plain;
	charset=ISO-8859-1;
	DelSp="Yes";
	format="flowed"
Content-Transfer-Encoding: quoted-printable
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

Hello Johan,

a most interesting theory to explain the "lost dB's".
Looking at the patterns:
am I right to conclude that not-so-perfect ground will only attenuate =20
the surface wave (radiated at 0=B0) but will not affect skywave (or even =20
improve it a bit)?

73, Rik  ON7YD

Quoting "Johan H. Bodin" <jh.bodin@telia.com>:

> Hello,
>
> Rik wrote:
>> It seems that even on 504 kHz still a lot of power is "absorbed"  =20
>> near the antenna.
>
> If there are a few dBs still missing when all near field losses have
> been taken into account, I would guess it is time to blame the
> non-perfect ground. The lower the ground conductivity, the weaker
> the low angle radiation radiation from the antenna. I don't think FS
> measurements taken at ground level are reliable, there are too many
> "it depends..." factors involved. Unfortunately, at 1km distance, the
> FSM antenna has to be raised to almost 500m height to get a reading
> at 25 degree elevation... Tethered balloon?
>
> 73
> Johan SM6LKM


Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm