@jcaron I have two antennas which perform more robust. One, which looks similar, but is 22 cm long (18 cm up from the hinge). That one shows a nice current profile, peak in the middel of the "active" section and going down to almost zero towards bot sides. The other is a home-brew ground plane antenna, along a recipe from the ttn forum, which also work pretty well. Both are not very sensitive to touching the xxPy and moving.
Compared to these the PyCom antenna performs between 6dB and 16 dB, depending on placement and touching. I have my xxPY built into a aluminium box with the antenna connector at the shorter side. The PyCom antenna shows some current at the connector, which explains the sensitivity to touching.
Picture: GP antenna on FiPy in a box, built from a SMA connector an 1.5 mm wire. Tip wire it 82mm, the radial are 86 mm.