My Home Made NCPL (YouLoop Clone).

 I made a prototype version of the NCPL (Noise Cancelling Passive Loop) receiving antenna.

This version is the same size as the YouLoop, but made with RG-58 cable, cross soldered (shield to inner and inner to shield at the top, then pushed through a hula hoop plastic tubing.

The ends of the tubing are inserted into a distribution box for electric wiring at the bottom. The shields are soldered together there, and the inner conductors are fed to a transformer made with 2x4 windings on a type 73 binocular ferrite core, one end connected to the shields and to the ground part of a SMA connector, the other end to the center of the coax connector. A better mechanical construction is needed, but a preliminary outdoor test can be made when the weather permits.

Testing:

Under test the home made loop behaved, essentially, as the commercial loop with respect to frequency response and signal strength. Not unexpected, and encouraging for the next experiment with NCPLs, another loop almost 2.5x the size of the original.

Due to the small size of the loop, signal strength on the lower bands is quite low. Experiments with amplification are in order.I suspect that the S/N can be improved significantly on MW/LW for this antenna, because many receivers/transceivers have low sensitivity below 1.6MHz, and the atmospheric noise is quite high on the low frequencies. I found a simple 2 transistor design presented by N1KPR, with 15-20 dB gain and a reasonable dynamic range, and I think this should be the first test with low frequency amplification, and probably be mounted outdoors near the position of the antenna. After this I can think of making an indoor distribution system with some band splitting, more amplification (pet band) and possibly a pre-selector system for the receivers. 

For the larger NCPL the intention is to use the thin Teflon coax cable (RG-316(?)) for inserting in the tubing, because the fitting holding the tubing parts together will probably not have enough space to fit the cross connected pieces of RG-58 inside. The thin RG-174 could probably be used, but the Teflon cable is more heat resistant when soldering, and more mechanically stable. Experiments with a different transformation ratio and some amplification should be made to see if the VLF band (down to about 10kHz) can be covered with sufficient sensitivity.

Because the system will be more usable in the winter half of the year, there is no great haste needed, but the bigger loop should definitely be made and tested. After that, I should focus on 2, 4, 6 and 10m. The Sporadic E season is right around the corner.