[Lowfer] Grounded loops

[Bill Ashlock]

Hello fellow looper from afar!

>With xfmr fed loops there is no reason NOT to have the loop grounded >at 
>one point.

Some of my TX loop designs have not cared when I connect a ground at the 
bottom. BTW, they are typically transformer fed and use the series resonant 
mode. My latest designs however that use the trees as the main support 
system indicate a loss of Q causing a ~3db reduction in loop current if I 
attach a ground at the bottom. I suspect that if I were to attach a ground 
wire at the very top there would be no loss in Q. This would not offer much 
improvement in component protection, however, since my spark plug at the 
bottom fires at ~1kv and the transformer isolation provided to the primary 
would be many times this voltage.

These loops are sure the tree-lovers savior aren't they? Or maybe that 
should be the worded "the Lowfers tree saver"?

Bill A


>Mine is fed this way and I can measure virtually no performance
>difference on receive or transmit with or without a ground connected to one
>bottom corner of what is basically a vertical rectangular loop (fifty feet
>long and 25 feet high). I guess ideally it (the ground) should be applied 
>in
>the middle at the top or bottom, but  that assumes the loop is far enough
>away from other nearby 'stuff' that application of a asymmetrically located
>ground will upset near field noise source rejection-- a function of loop
>capacitive balance to everything else.
>With my loop- just ain't so- it's probably within a couple of feet of just
>about everything down the back of the yard- at least at the bottom, and 
>well
>up the two sides.  And the upper bit has trees etc all through it. In fact
>it's so well dug in down there it's a wonder it works at all- and there
>surely is no danger of a lightning strike- too much other stuff higher and
>in the way.
>  BUT........!!!
>
>73
>  Dave
>  ZL3FJ
>Christchurch
>New Zealand
>


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