40 mtr band short beverage`s last edited 09.2019

Test`s  / Development phase

Antennas feed with a 75 Ohm cable

Important technical aspects

- Antenna measurements through 50 Ohm Zin transformers  ( measuring system impedance). Then redesigning the transformers for Zin 75 Ohm for later use ones.  (beverage feed with a 75 Ohm coax cable)
- Antenna measurements through Zin 50 Ohm transformers. Then redesigning the transformers for other useful ones for impedance Z 75 Ohm. 
- Transformer with the minimal capacitance between the antenna winding and the rest of the system.

- to set the no-load winding impedance at the lowest frequency at
about five times the RF impedance across that winding




- selection of terminal resistor resistance value.  Based on pre-determined wire impedance and taking into account grounding resistance. Verification, among others, by measuring "waviness" of SWR chart changes in the range from 5 to 25 MHZ.
The purpose is to minimize the back radiation pattern at 30 degrees elevation angle.


Length currently under test
1.     53.5 meter
2.     68.6 meter