Off center fed multiband antenna for 40 - 20 - 10 meter bands with frequency ranges of 7000kHz to 7200kHz, 14000kHz to 14350kHz, and 28000kHz to 29700kHz with overall length of 20.5 meters (~ 67 ft.) (arms length: 13.65m/ ~45ft., 6.8m/ ~22ft.), with 0dBd gain on 40m band. A maximum power load of 1200W PEP SSB with the 4:1 ratio balun
|Frequency range||7000 Khz – 7200 Khz, 14000 Khz – 14350 Khz, 21000 Khz – 21450 Khz a 28000 Khz – 29700 Khz|
|Working band of the antenna||Approx.130 kHz for SWR less than 2 (depends on the placement of the antenna in space)|
|Arms length||13.65m/ ~45ft., 6.8m/ ~22ft.|
|Overall length||20.5 meters (~ 67 ft.)|
|Gain||0 dBd for the 40 meter band|
|Maximum power load||1200 W PEP SSB|
|Antenna feed||50 ohm coaxial cable|
|Mounting height||not less than 6 meters (~20 feet) (the higher, the better)|
The materials used to build this antenna have been selected with an emphasis on the best electrical and mechanical properties, and resistance against outside weather conditions. An equally important factor is the durability of these properties in the future.
For the dipole arms a hardened and prestressed copper line with a cross-section of 2,5sqmm and a harder PVC isolation is used.
On the box side of the dipole arm the wire is tipped with an eye for a M4 screw (made by ZES Dolny Kubin).
It is isolated by a shrink tube on both sides. The mechanical connection with the balun is made by using a simple wire loop secured with a duplex wire clamp and, on the hanging rope side, a ceramic isolator (type 16C01 made by MFJ is used), also secured with a duplex wire clamp.
The antenna balun with a ratio of 4:1 and a maximum power rating of 1200W PEP SSB is made from a waterproof box of IP56 made by SCAME, model 686.205.
On both sides of the box are screws with closed hook ends; The screws are of size M5 and are made from anticorrosion steel for durability.
A brand name SO239 connector is used, with teflon diaelectricum and gold plated middle socket, bolted to the box via anticorrosion steel screws and nuts.
The balun transformer is wound on a ferite toroid core model AMR R2 with the respective measurements of (outer x inner x height) 50 x 25 x 20 mm.
The arms of the dipole are electrically connected to the transformer through a pair of M4 bolts and nuts on both sides of the box.
The connector on the antenna serves only to electrically connect with the coaxial cable. For bearing the coaxial cable, use the attached rope (with inner core made by LANEX).
After the antenna is tuned, it is necessary to insulate the ends of the arms with shrink tubing to prevent water intrusion.
The warranty does not cover damage made by overloading the balun with more power than specified on the balun`s label.