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Many people are attempting to implement the #Airspy #YouLoop antenna without paying attention to some details. Here's a summary of things one should take care of.
Full details here: https://airspy.com/youloop
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#Airspy #YouLoop #Thread
Full details here: https://airspy.com/youloop
#Retweet and #SpreadTheLove
#Airspy #YouLoop #Thread
In most implementations, the whole point of noise cancelling has been made irrelevant because of small mistakes:
1) Try to have a perfectly symmetric loop shape. Failing to achieve symmetry makes the antenna sensitive to the local electric noise.
#Airspy #YouLoop #Thread
1) Try to have a perfectly symmetric loop shape. Failing to achieve symmetry makes the antenna sensitive to the local electric noise.
#Airspy #YouLoop #Thread
2) Use a high precision BALUN to avoid introducing gain and phase imbalance. This also makes the antenna sensitive to the electric component of the electro-magnetic spectrum.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
3) Given this antenna is passive by nature, it has a lower gain than its active counterpart. The BALUN must also have a very low loss, otherwise, the weak signals are lost before they have a chance to reach the receiver.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
4) In the official implementation, we use high precision 18 GHz SMA cables with perfect matching. The manufacturer of these cables also serves the spectrum analyzers market. Again, the phase/amplitude mismatch results in lower performance.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
5) This design has a high impedance in frequencies lower than 10 MHz. If you are using a low-impedance preamp, you will load the coax loop and create a sharper (narrow band) lobe.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
6) The whole design was optimized for the #Airspy HF+ Discovery (and to some extent the HF+ Dual Port). These receivers have an MDS lower than -140 dBm, which is suitable for passive loops. Don't expect your regular Radio or SDR to perform similarly.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
7) If you ignore these points, just please refrain from comparing your random variant of the #YouLoop to other antennas, or just don't call it #YouLoop (because it is not). I have seen a lot of videos with all these gotchas perfectly illustrated.
#Airspy #YouLoop #Thread
#Airspy #YouLoop #Thread
8) That said, with a little of care and proper understanding of the theory, one can achieve good results, like this detailed DIY. tutorial by Thomas of #SWLing blog.
https://swling.com/blog/2020/04/diy-how-to-build-a-noise-cancelling-passive-loop-ncpl-antenna
#Airspy #YouLoop #Thread
https://swling.com/blog/2020/04/diy-how-to-build-a-noise-cancelling-passive-loop-ncpl-antenna
#Airspy #YouLoop #Thread
