A Biconical Cage Group working over the prescribed frequency range & power handling applicable to a specific Balun. The two baluns have been modified to accept a range of 3 smaller cages to address specific requirements for NSA using the RSM procedure. But more importantly, if the EMCO 3108 balun is substituted for the EM-6192A then for shielding tests it makes a good transmitter where space is seriously hampered, e.g. within vehicles where space is critical.
Essentially you order a case containing three cage sizes .
Dimensions of cages to balun are:-
BC-S: 53cm (tip to tip). Diameter: 18cm
BC-M: 67cm Diameter: 25cm
BC-L: 88cm Diameter: 36.5cm
Balun 3108 takes 300 Watt. Balun 6192A handles 0.5Watt.
The standard biconical has a tip to tip of 1.3m with a diameter of 52cm.
At the lowest frequency of operation ( 30MHz) the smallest cage is about 8-10 dB down in field strength on a standard cage but as the frequency rises toward the 300MHz end the difference becomes minimal. However, the useful range with the smallest cage is toward the 1 GigaHertz end. The disadvantage is in the linearity of gain over the range. However, if spot frequencies are chosen where shielding is concerned, prudent selection of frequencies can ensure an adequate dynamic range with just 50 watt feeding the EMCO 3108 balun seen here to the right. Select your Balun at time of order.