Message-ID: <4A687388.4050801@usa.net>
Date: Thu, 23 Jul 2009 16:28:24 +0200
From: Alberto di Bene <dibene@usa.net>
User-Agent: Thunderbird 2.0.0.22 (Windows/20090605)
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <1MTixd-0cGXyK0@fwd00.t-online.de>
In-Reply-To: <1MTixd-0cGXyK0@fwd00.t-online.de>
Z-USANET-MsgId: XID905NgwoCC2064X40
Subject: Re: LF: Loop discussion
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


James and Ha-Jo,

   thanks for your answers and considerations about using the loop itself as the primary of the transformer.

I thought that it could be a good idea, based on this consideration :
If I make a single turn loop using copper tubing, it will have a very low resistance, guesstimated between one 
thousandth and one hundredth of a ohm. A regular primary winding on a transformer will have a resistance at least an 
order of magnitude greater. IMHO, this affect negatively the Q of the loop... if I use the loop as primary, closing the 
single turn on itself with a good soldering, the Q would be unaffected, also because the secondary is not loaded...

In fact, my intention was to have a high number of turns on the secondary, let's say at least 20, directly connected to 
the gate of a FET used as a source follower. This, again IMHO, would have the benefit to leave the Q of the loop at its 
unloaded value, and to have a great voltage gain, given by the high turn ratio of the transformer...
Naturally, this will imply that the loop cannot be tuned, but there are applications for untuned loops.

Is this line of thinking completely wrong ? Thanks for any considerations.

73  Alberto  I2PHD