Building the Portable Convertible Vertical

(Thanks to Jay ad5pe, and Jeff kc5ert for assembling this info and making it available to us.)

Parts: 

A Conduit – base (1) 4’6” 
B Conduit – 10m (1) 3’6 13/16” 
C Conduit – 12m (1) 1’3 11/16” 
D Conduit – 15m (1) 1’6 15/16” 
E Conduit – 17m (1) 1’11 3/8” 
F Conduit – 20m (1) 3’5 3/4 ” 
Couplers (5) 
Star washer (1) 
Screws (6) 
Ring Terminal (2) 
Board (1) 
Clamps (2) 
Radials (8) 18’ of network cable 

The A conduit is the base – it fastens to the board with the 2 clamps and 4 screws. Positioning is not critical, but keep the base end up about 2” from the end of the board. The board will sit on the ground with the antenna erected, and is the “base insulator” to keep the vertical radiator off the ground. Pre-drill a hole in the lower end of the A conduit for the coax. Put this slightly below the bottom clamp ,positioned out.

Strip a couple of inches of your coax pigtail jacket. Fold the braid back and pull the center conductor (with dialectric) out through the braid. Leave the dialectric in place. Strip ¼” of the dialectric off the center conductor.

Instal a ring terminal on the center conductor, and fasten to the predrilled hole in the A conduit with a star washer and screw.Strip the jacket off the network cable. Untwist the inner conductors, yielding 8, 18’ wires. Fasten all 8 wires to the coax pigtail braid. Use a ring terminal and a screw into the board for a strain relief. Coil the wires up to keep them out of the way until you set up the antenna. 

For 10m operation, attach the B conduit to the A base conduit with one coupler. Guy the antenna approx. 2/3 of the way up (any nonconductive rope with work). You will need the appropriate connector to match your radio on the other end of the coax. 

For lower bands, add the appropriate conduit stubs using the additional couplers. For 20m, you need all six pieces. You will have to move your guys up, keeping them 2/3 of the way up the vertical radiator. Also, unless you need to frequently switch bands, (in which add them in order by band) the antenna is more stable with the longest stubs towards the bottom. In other words, for a day of 20m operations, A, B, F, then C, D, and E stubs puts the shortest stubs up top and makes the antenna flex less, but to change to 17m you have to break the antenna at both ends of the F stub, and then reconnect C to B. 

The below spreadsheet was contributed by Edd, kk5edd. 

Band Lo Freq. Hi Freq. Freq. Avg. LnthFt.
20 14.225 14.350 14.288 16.378 3.478
17 18.110 18.168 18.139 12.900 1.947
15 21.275 21.450 21.363 10.954 1.579
12 24.930 24.990 24.960 9.375 1.306
10 28.300 29.700 29.000 8.069 3.569
Base       4.500  
Band             Total Mine Jay’s
20 4.500 3.569 1.306 1.579 1.947 3.478 16.379 16’4 9/16″ 16′ 51/16″
                  12′ 10
17 4.500 3.569 1.306 1.579 1.947   12.901 12’10 13/16″ 13/16″
15 4.500 3.569 1.306 1.579     10.954 10’11 7/16″ 10′ 11 1/2″
12 4.500 3.569 1.306       9.375 9’4 1/2″ 9′ 4 1/2″
10 4.500 3.569         8.069 8’0 13/16″ 8′ 2 7/8″
Base 4.500           4.500 4’6″ 4’6″
3’6 1’3 1’6
20 4’6″ 13/16″ 11/16″ 15/16″ 1’11 3/8″ 3’5 3/4″
    3’6 1’3 1’6    
17 4’6″ 13/16″ 11/16″ 15/16″ 1’11 3/8″  
    3’6 1’3 1’6    
15 4’6″ 13/16″ 11/16″ 15/16″    
    3’6 1’3
12 4’6″ 13/16″ 11/16″
    3’6  
10 4’6″ 13/16″  
Base 4’6″    
Edd also contributed his illustration on how he configured the assembly of the antenna to suit his needs