MOBIUS cross loop antenna
#1
Hi all
I`m a new participant and I had running the system blue, first with two 200mm indoor rod ferrite antenna, that later I changed to MOBIUS cross loop. The system seems working very well with ferrite antennas, but it pickup strong noise from switching power supply in my house and Neighbors (I live in an apartment), especially from cell phone chargers. So I build a cross MOBIUS loop with coaxial cable HELIAX 3/8", with PL 259 connectores, and respective SO panel connector. I used a square metal box for coaxial connectors, that shunt all shields in the point oposite to the inverter connections of the coaxial cable. I had run this antenna for some days, and it working great, with much lower noise and more directivity that give the possibility of optimizing the noise floor. With this "shield shunted" MOBIUS cross loop I was able to detect lightning at 6600Km. I read about MOBIUS and I always saw that the shields were not interconnected. So, I decided buil a new "shield isolated" MOBIUS cross loop and test again. I was desapointed, because the noise go up and the directivity drop. I tested this "isolated loops" by a pair of days, and the detection drop a lot. Again, I returned to the "Shield shunted" cross loop, and the detections ratio was go up again. I use a gray color toroid transformer with 50 turns of 0.25 isolated wire.  Has someone  done other tests with MOBIUS cross loop?
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#2
Made my first Mobius Loop Antenna a week ago.

It consists of 4 turns of RG6 Quad Shield Coax, (Just because it was readily available).
600mm in diameter & mounted in 65mm PVC pipe.
Not finished yet; need to shorten the leads & move it to it's final location.

Would be interested in feedback & in particular whether adding  transformers will be of benefit.
(Have some toroids on order).

Would also like to know what the major difference in it being a Mobius loop, Vs just a plain coax loop is,
considering it's only whether it's joined at the centre or not, (and the shield connected).

Obviously my first attempt & know there's still a lot to be learnt.

Thanks

Phil.
 
   
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