Various Tube sizes for Power Splitters. G4CYA

For 2 antennas Zt (calc)=35.4 ohms For 4 antennas Zt (calc)=25 ohms

 

D d Zt (act) Z comb VSWR aref D d Zt (act) Z comb VSWR aref
mm mm ohms ohms   dB mm mm ohms ohms   dB
7 4 38.2 29.2 1.17 22.5 6 4 28.9 16.7 1.34 16.7
9 5 39.9 31.8 1.27 18.4 7 5 24.8 12.3 1.02 40
10 6 35.3 24.9 1.01 46 8.5 6 25.5 13.0 1.04 34
13 7 41.8 34.9 1.40 15.5 10 7 26.0 13.5 1.08 28
14 8 38.2 29.2 1.17 22.5 11.5 8 26.4 13.9 1.11 26
15 9 35.3 24.9 1.01 46 12 8 28.9 16.8 1.34 16.7
16 9 39.2 30.7 1.23 20 13 9 26.7 14.2 1.14 23.8
17 10 36.5 26.6 1.07 29.5 14 10 24.8 12.3 1.02 40
18 10 39.9 31.8 1.27 18.4 15 11 23.2 10.8 1.16 22.5
18.5 11 35.8 25.6 1.03 36 17 12 25.5 13.0 1.04 34
19 11 37.4 27.9 1.12 25 18 13 24.1 11.7 1.07 29.3
20 12 35.3 24.9 1.01 46 20 14 26.0 13.5 1.08 28
21 12 38.2 29.2 1.17 22.5 21 15 24.8 12.3 1.02 40
21 13 33.4 22.3 1.12 25 22 16 23.7 11.3 1.11 26
22 12 40.9 33.5 1.34 16.7 24 17 25.3 12.8 1.02 40
22 13 36.2 26.2 1.05 32 25 18 24.3 11.8 1.06 30.8
23 14 34.4 23.7 1.06 31 26 19 23.4 11.0 1.14 23.8
25 15 35.3 24.9 1.01 46 28 20 24.8 12.3 1.02 40
27 16 36.0 25.9 1.04 34 30 21 26.0 13.5 1.08 28
28 17 34.6 23.8 1.05 32 31 22 25.2 12.7 1.02 40
30 18 35.5 24.9 1.01 46 33 23 26.3 13.8 1.10 26
32 19 35.9 25.8 1.03 36 35 25 24.8 12.3 2.03 36.5
33 20 34.7 24.0 1.04 34            
34 20 36.5 26.6 1.06 31            

The values shown in Bold are the preferred values giving the best match.

Usable dimensions for the square section material (DxD) and the tubular inner conductor(d) of l/4 line transformer used to combine two or four 50 ohms antennas to 50 ohms coaxial cable.