when I looked for more information about my antenna (base coil loaded half sloper) I found interesting antenna also for restricted space.
In fact the vertical part is helical vertical where 11.7m of insulated 2.5mmsq wire is wounded on the 5m of the fiber glass pole including the wire going to point A for feed line. The spacing for the winding is approx. 1.5cm.
The 2x 18.1m of the insulated wire used for radials on the ground is compromised solution for that installation. Definitely it's needed better grounding system and 16x 16m is recommended as minimum where 3dB loss is expected.
Well I did not tested it but for those who are space limited it can be inspiration for experiments.
Do not hesitate to share with us Your experiences with compromised antennas like this.
73 - Petr, OK1RP