Mime-Version: 1.0 (Apple Message framework v1251.1)
From: John Rabson <john.rabson@numeo.fr>
In-Reply-To: <4F230085.2060504@m0dts.co.uk>
Date: Sat, 28 Jan 2012 09:54:26 +0100
Message-Id: <5CB0763E-E801-47BE-8D51-E75122FD6C10@numeo.fr>
References: <4F209013.2030803@iup.uni-heidelberg.de> <4F219B7E.6090001@m0dts.co.uk> <4F22F36A.6090209@iup.uni-heidelberg.de> <4F230085.2060504@m0dts.co.uk>
To: rsgb_lf_group@blacksheep.org
Content-Type: text/plain; charset=us-ascii
Subject: Re: LF: Conds
Content-Transfer-Encoding: quoted-printable
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-AOL-SCOLL-URL_COUNT: 0  
x-aol-sid: 3039ac1d60554f23b8097985
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


Rob,

You might well find it useful to build an RF ammeter and  (if you have =
an oscilloscope) a Scope Match. See Chapter 10 of the Radio =
Communications Handbook.

I have had the same problems with earth resistance as you have. In my =
case, multiple earth spikes near the feed point do not seem to do much. =
Their total resistance when connected in parallel is about 24 ohms, but =
the resistive component of the feed impedance is about 150. I am =
experimenting with earth mats, but think I will probably need to improve =
the insulators at the high voltage points, and move those points further =
from the trees.

John
F5VLF

On 27 Jan 2012, at 20:52CET, Rob, M0DTS wrote:

> My TX is now working all be it fairly QRP 90W ;-)
>=20
> Antenna is 53m horizontal at ~9m high.. a droopy 'T' single strand =
copper all the way.
> I'm also receiving on this antenna too with much better results than =
the loop i have.
>=20
> Problem is going to be getting enough routes to earth, my last =
attempts were getting ~1A antenna current with the same power but it =
looks much worse on G4WGT's grabber than last time so i guess it's less =
than 1A.
> Will do some more improvements over the weekend.
>=20
> Rob
> M0DTS
>=20