Balun for HAM Radio antenna up to 800 watt CW/SSB with built-in cut-off choke

Description

Several years of operation of baluns at the "Radial" test site have shown that for some types of antennas, in addition to asymmetry, there is also not enough current cutoff from the cable braid.
The appearance of parasitic resonance due to the "antenna effect" of the feeder forced the installation of a current choke.
With its inclusion, the problem was solved and the resonances of the antenna began to clearly respond on the panoramic SWR meter without any parasitic bursts.
The current choke is made of a fluoroplastic cable, which is wound on 12 ferrite rings. Cutoff currents are shown in the DR diagram.
Considering that in the modern world there are a sufficient number of competing manufacturers, and many professionals may envy the abilities of radio amateurs (in a good way), we want to pay special attention to the fact that we do not just produce baluns, but also periodically test and control them for the main indicator is the coefficient of asymmetry. It is this parameter that we sell and are responsible for.
Therefore, the following improvements are implemented in our new baluns:
1. All baluns have a cut-off choke. This ensures elimination of the antenna effect and stablizes parameters of field antennas independently of the feeder location.
2. All baluns are manufactured basing on Wide Band RF Transformers on Ferrite Tubes
. This means that the power is passed not by a magnetic field through the core, but over wires that considerably reduces losses of the entire balun.
3. Baluns are completely leak-tight due to the sealing by a two-component compound.
4. Mass of the baluns is reduced due to the decreased dimensions, light-weight plastic enclosure, absence of contact screws, role of which is fulfilled by the conventional multi-core wires.
Operating frequency band, MHz
2-30
Impedance ratio
BR-800-1.5DR
50:75 (1:1.5)
BR-800-2.5DR
50:112 (1:2.25)
BR-800-4DR
50:200 (1:4)
BR-800-6DR
50:300 (1:6)
BR-800-9DR
50:450 (1:9)
Impedance, Ohm
50
Insertion loss, dB
0.23-0.45
Input power, not more, W
(CW, SSB)*
800
Asymetrict factor no less, dB
25
Connector
SO-239
Weight, g
750-790
Length/Width/Depth, mm                          112x61x346