I just wanted to put a quick post up as I am in a new QTH and decided to make a larger SWL receive-only loop than my current 30cm diameter one in the hope it would catch a slightly better signal and help when things weren't booming in and I was struggling on the small loop.
I made a much larger 75cm diameter loop and after hours of tests right the way across the board from 4mhz right up to 21mhz I can honestly say it made no difference whatsoever. It performed identically to the loop that was barely 30cm in diameter.
In a way this was good news to me, as the larger loop is unsightly indoors. But it made me think that perhaps this was the reason AOR and PK Loops had settled for these smaller loops that sit neatly and comfortably by your side in the radio shack. Up until now I had assumed the smaller AOR loop was a compromise over the larger Wellbrook loops.
But my own tests have proved the extra size doesn't affect reception. Obviously I realise if you are transmitting then it's a whole different ball-game, but for anyone thinking of building a loop and wondering what size to go for, bigger isn't better.
I have now hacked a large piece of my loop and reduced it to a more manageable and attractive 1 foot diameter as a back for my other small loop.