After many requests we have created a compact, special balun for single band loop (Sky loop or Delta loop) antennas. The CB-2.25-1500 is a CUBE(TM) enclosure containing a multi-core, broadband 2:25 impedance transformer (50 ohm coax input to 112.5 ohm balanced output) in series with a 1:1 current balun for extra common mode current choking to keep RF current off the outside of the coax braid and on the antenna where it belongs. The extra choking action also means that the coax feed line will not act as a radiator causing unnecessary RF interference (RFI). Rated for full 1500 watts PEP and 450 watts CW (ICAS). 1.8Mhz – 61 MHz.
CB-2.25-1-1500EB is housed in a 4” x 4” x 2” waterproof housing with SO-239 input and stainless steel eye bolts on the side for ease of connection to your wire antenna. Top eye bolt acts as an antenna hoist. Also available with top studs for post or wall mounting (Model # CB-2.25-1-1500TS)
Loop antennas should be cut for 1005/F(MHz) in total length, where F (MHz) is the lowest frequency to be used. For 3.5MHz this equates to 288 foot perimeter (square, delta, multi-side ok).
Production Note: These hybrid baluns are special order and made to order for each customer. Please note that shipping will be approximately 2-3 weeks after order placed depending upon our existing production schedule.
Pictures show 2-1 balun but you will receive the 2.25:1 balun with 1:1 hybrid in a single enclosure.
Also make sure you connect a good RF ground to the transceiver ground post.
Note to Flex Radio users: Use snap on ferrites for firewire cable, speaker cable and mic cable, Ring ferrites for Antenna output and DC power.
For additional RFI suppression, use a feed line choke at the antenna to suppress common current on the coax feed line – see our store for feed line choke alternatives for use at the antenna.
If you use a linear amplifier we have RFI kits for linear amplifiers that help suppress RFI in your shack or in your neighbor’s house.