[Lowfer] Loop-D-Loop

[Bill Ashlock]

>Something tells me no, that good performance would require a clear and elevated placement. If true, then by what measure and how high?
 
Peter,
 
John is basically correct in saying that elevation is not a factor - and who would doubt his excellent record of weak-signal catches. There are a couple of exceptions in loop receiving that I have noted. First, if there are any buried wires, connected or not connected, anywhere near the loop, they will tend to radiate signals (often interference) to the loop. So in this case raising the loop will help S/N. I highly recommend the technique of walking around with a 3' loop (a size that one can handle) and portable SVM (here we go again Mike :), or even your main receiver on an extension cord, to determine the lowest noise location. Secondly I have found that in the case of deep woods looping that nearby trees can have a small effect on the loop null. Tall trees can be modeled as high resistance vertical antennas, low performance ones at that, which have a associated E-field and H-field around them.
 
And another two cents worth of comment: I wish someone would do a careful investigation into the effect of receiving loop size in the 3' to 10' range for very weak signals. This would have to be a Bill Bowers type of very careful investigation similar to what he did for loading coil Q and other lowfer topics in his excellent  'Lowdown' articles. I guess I should have done a Lowdown article on all the TX loop testing (multiturn results, ground spacing results, tree effect results, etc) I did way back in the pre-TX loop days but I figured the interest would have been low because few believed in those things. 
 
That's all.....
Bill> Date: Thu, 10 Jul 2008 07:33:54 -0500> From: pbarick at wpo.cso.niu.edu> To: lowfer at mailman.qth.net> Subject: [Lowfer] Loop-D-Loop> > G'day gents,> > Here's a loop question on my mind.> > I'm reworking an old LF loop wooden frame for 600M. It will be almost 10 X 10Ft and near-ground mounted.> (The rebuild is adding two more support arms and refinishing the paint.)> > So Bill's loop-in-the-trees works have shown how immune such a large wire loop is to adjacent and conductive objects. Then by extension would a smaller, multi-turn loop behave in kind, ie, near trees, buildings?> > Something tells me no, that good performance would require a clear and elevated placement. If true, then by what measure and how high?> > Cheers - Peter> _______________________________________________> >From the Lowfer mailing list> Send messages to: Lowfer at mailman.qth.net> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer