Portable antenna
The antenna is made of copper wire with a diameter of 2.5 mm and a length of about 45 cm Coil L1 contains 5.5 turns (step 5.5 mm). The inner diameter of 12 mm from the Top of the antenna is soldered metal "umbrella", providing her widely-banding and reduces the radiation resistance. To the lower end of the antenna connector soldered SR50. The antenna, shown schematically in Fig. 1, designed by hams W6AAQ and W6TWW for installation on vehicles. On the parameters it is close to vertical antennas having a length of 5/8A .
"Pounder"
K1TD, using the theory of automatic process antennas, constructed up to the antenna, which because of its small weight (about 500 g) was given the name Pounder (translated to English means pound). Schematic drawing of this antenna is shown in Fig. 2.
The antenna elements are made of dural pipes with a diameter of 6 mm, which is attached to the supply line with M4 screws. To configure from the outside elements, it is expedient to provide for the possibility of screwing them in M4 screws with a length of about 50 mm.
The supply line is made of two dural area HH,5 mm, between which is located an insulating spacer (made of organic glass, Teflon, etc.) with a thickness of 3...6 mm Between the corners of the bonded side of the element L4 M4 screws from the side of the L1 - RF connector which is connected to the feeding coaxial cable. To the mast antenna is attached using a traverse length of about 1 m of insulating material.
Balancing antenna coaxial cable near the plug is wound (six turns) on the ferrite ring.
The antenna has a gain of about 5 dB. The SWR on the edges of the operating range is within 1...1.8. The ratio of the radiation back and forth approximately equal to 20 dB.
Author: George Chliyants (UY5XE) Ukraine, Lviv; Publication: N. Bolshakov, rf.atnn.ru