For portable use i use almost the same antenna i have constructed for my QTH , with the difference that i used 20 meter (65,6 feet) of wire for each leg of the dipole. On each end of the dipole i placed an ceramic egg, on witch is a extension of 3 meter (9,8 feet) of 4 mm (0.15 inch) polyester wire (picture 1 below). In the middle of this dipole i constructed the same feed line of 15 meter (49,2 feet) as described ad my QTH HF antenna page. On the end of the feed line i placed a special connector from the Conrad company. This connector is springy, so this connection stay's optimal.

dipole antenna
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If i want to extent the feed line in the field i can connect 2 extensions of 10 meter (32 feet) to the feed line. For this i used the same connectors. These 2 extensions are standard equipment in my crash kit
This antenna will be used with the portable mast and on the end of both lags, pools of bamboo (see picture 4 above) will be placed to raise the legs on the end of the rope on the dipole. These bamboo pools are made out of two rods of 2,10 meter (6,8 feet) long, which give a total length of 4 meter (13,12 feet) of height. The dipole can now be straitened by the two attached guy lines. These lines also will keep together the two poles when stored.