[Elecraft] Efficiency of MFJ remotely-tuned loop antennas

[Warren Merkel]

Resistive Losses around the loop are the biggest factor limiting 
efficiency.

My friend, Paul Casper, K4HKX has done very extensive investigation and 
documentation of Mag Loop performance.  His loops exhibit excellence in 
both Art and Science.   I'd recommend taking in his findings posted on 
his QRZ page.

https://www.qrz.com/db/k4hkx

You might get distracted looking at his other antenna creations.  I 
wrote the code running in the custom antenna control head.

The Mag Loops start way down at Section 7.   The progression of loop 
designs is staggering.  You might find his HF mobile loop quite 
interesting too.  He uses a KX3 + KXPA100 with his mobile loop.


Warren Merkel, KD4Z


On 1/19/2021 12:17 AM, elecraft-request at mailman.qth.net wrote:
> Date: Mon, 18 Jan 2021 20:17:38 -0700
> From: David Gilbert<ab7echo at gmail.com>
> To:elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Efficiency of MFJ remotely-tuned loop antennas
> Message-ID:<2cd662a2-5959-f155-547c-815e6b2429b7 at gmail.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> 
> You are neglecting the losses in various connections in the system ...
> including possibly the construction of the capacitor itself.? I don't
> believe that they are insignificant.? There is a reason why top quality
> variable capacitors often use welded plates.
> 
> I would also guess that contact resistance is worse for dissimilar
> materials, such as a copper wire to an aluminum tube.
> 
> Yours is a limited theoretical analysis ... not a practical one.
> 
> Dave?? AB7E