JUMA TC Turnstile Controller for Circular Polarization

This is Revision D of JUMA TC

JUMA TC provides the 90 degrees phase shift to two dipoles (ANT-X and ANT-Y) in turnstile 90 degrees configuration. Both of the two antennas must be fed with the same length of separate coax cables. The Left hand (LHCP) and Right hand (RHCP) polarization can be selected with the rotary switch SW1 as well as one of the dipoles can be selected singly. The selection can also be done remotely with 2 logic signals by turning the rotary switch to REMOTE position. The PTT signal is used to swap the polarization between transmit and receive. JUMA TC requires only 50mA of 12V DC supply. The RF power handling capability is up to QRO power.
Circular polarization provides many known benefits for NVIS communication. Additionally the quadrature hybrid in JUMA TC provides SWR 1:1 on whole the band by delivering the reflected power to the dummy load in the band edges. The two dipoles in 90 degrees configuration should be tuned to a same frequency.



JUMA TC PCB layout

SMD assembled photo

JUMA TC revision D supports both internal and external dummy load. The internal dummy load (R16, R17) is for TX power up to 200W. The external dummy load is recommended for TX power over 200W up to legal power. Use only one of the dummy loads.
JUMA TC supports the most important NVIS bands 80 meter and 160 meter. Only the iron powder core and two capacitor are different. See the differences and other details in the schematics.