The new loop experiment

 Much long after designing an experimenting with wire antennas i decided to experiment with a Moebius antenna  design similar to the the home made youloop design as shown in the swling page 

Instead of the R58  types of cable I used RG6  the standard cable used for TV and satellite antenna lead that was very  handful together with some wire benders zip ties and cable terminals I used also the soldering probe and solder for any required joints but proved unnecessary as  the zip tie was quite tight over the cabe for all the time i was experimenting

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I made a mini change in the design :  I cut the cable in the middle, changed the poles in the middle of the wire while for the remain end i turned the cable so that the middle core could be in parallel and connected with a terminal block

 

and here is on how the mid points were connected:  It was much easier to jeep that quite safe and steady instead to use the solder. Its more than 15 years since i stopped using solder for making some basic electrical engineering . I also know a few technicians nearby my house who stopped soldering as most work  is just plug and play with mother boards!

 

this si the inversion part ..

Together with  joining the antenna parts I added a 'cloth hanger' . an idea seen in a antenna building This retains the shape of the cable.  Face-group Some short self bent wire tights the cable  soflty over the hanger

For more experimenting i used two different  lead cables to connect in the SDR or in the radio:
- a twin wire as used for electricity connections of 0.75 m2
-a 1.5  meter RG6 cable as in the photo 

The results were poor : Using the PL330 radio seen no  significant change in terms of noise caneling as far as i tested.

Putting the antenna over the railings (ie the metallic fence) raised the SNR to more than 10 db  Seen also a minimal level noise deletion as the antenna was turned

Testing with the spectrum analyzer as above shows many ghost carriers across the bands As you can see there are some relatively strong signals in the lower two bands there is also a huge noise level 

Instead of the band to be in the clear the SDR shown highly numerous unwanted carriers .someone called that close proximity but i think that most of them are unwanted spurs coming from the SDR or PC

step 2 

Something was  wrong for sure . Testing once again all connections i understood that the cables shields ends were  not connected each other . I removed  the plastic cover of shield ends by 1.5 cm and again used a new zip tie to keep them connected

the shielded part is shown in black

Results were quite better in terns of noise canceling. Signals were again the same with better reception above the railings but the spurious signals insisted  to exist 

step3

Finally days after , I have found a  toroid that is around 1,5 cm in diameter.This is the only available in the city. the balun designed was 1:1 using appliance twin cable . This was my fist time making a balun. Really a relatively easy job!

Again the problem with  the unwanted carriers existed  in  the SDR.  Tested not only with the RSP1a but also with the Aisrpy Discovery which made both SDR and program getting mad from the unwanted carriers

I was strikingly disappointed and dismantled the antenna and  immediately ordered the Youloop from RTLSDR blog via ebay ata cost of 40Eu . I was quite hurried to end these tests with this antenna but no sellers in Europe have been found in ebay or any other platform  for faster delivery

In the mean time :this is the  spectrum analysis of the 10 m antenna when is connected via the cable to BNC connector to the SDR (any SDR )

hmm it was a mistake: the  antenna wire was connected in the ground wire if he wire to BNC adaptor. the fault ws made by the person who soldered all the ends and connected the ground wire on the positive

 

By using connecting the ground cable in the BNC adaptor it adds many spurious . if using the ground to the the SDR case the curve is quite different and reduces the noise level! 

This is what happens when using a VHF whip , in the HF bands ...

update : the original antenna  has been received much earlier than i could expect that is in just two weeks . the report is the next in my blog and works very well

https://zachs-radiopage.blogspot.com/2022/03/short-review-for-youloop-antenna.html

update2: I m also expecting a clone model for test for testing their boxes that seems bigger and possible harder than their youloop counterparts at least by view This is 10 euros cheaper than the youloop