Re: why does my 7.5" loopstick favor one direction above 1000 KHz?
Andy and Chuck,
The 7.5" loopstick PL-380 antenna design has a completely symmetrical coil (not offset to one side,) and is well isolated from the receiver circuitry (much more so than the internal stock loopstick), as shown in the attached photo. It has also been successfully built and/or used by at least a dozen DXers (including Patrick Martin, not a member of our Ultralight Yahoo group), all of whom have reported good results with it. None of the users have reported any issue with nulling or loopstick directivity, as Ryan has mentioned. The evidence would indicate that Ryan either has nearby metallic objects (indoors) which are skewing the symmetrical loopstick reception pattern, or a unique issue related to his own loopstick construction.
Ryan, as I recall, you originally had asked me to build the 7.5 loopstick PL-380 model for you. I have a couple of the models finished now, neither of which have any loopstick directivity issue (like you describe). As a final check, I would recommend that you get outdoors and check to see if your loopstick directivity issue still exists. If so, you may either send your finished model here for loopstick replacement, or simply exchange your finished model for one of the two finished MW test models here (both of which operate normally).
73, Gary DeBock (in Puyallup, WA, USA) .
Sent: Sun, Jan 12, 2014 7:30 pm
Subject: Re: [ultralightdx] why does my 7.5" loopstick favor one direction above 1000 KHz?
I agree with Andy. A ferrite loop figure 8 is normally very close to a figure 8. If something is wrong to the point where you notice it casually, something is badly wrong. This can also be confirmed if the nulls are not 180 degrees apart. The normal culprits are nearby objects and a lot of pickup (contamination) between the loop and the radio.
One question I'd like to know the answer to is the performance of a proper 7.5 inch replacement to the PL-380 rod. As far as I know, no one has reported the values for standard pattern skewing tests.