Hybrid 4:1 Balun + 1:1 Current Balun in one enclosure, 1.8-61 MHz, 1.5/5KW PEP - Loop, OCF AntennasProduct DetailsMPN: CB-4-1-1500TS/EB , CB-4-1-5000TS/EBCountry/Region of Manufacture: USAInput ohms/Output ohms: 50 in/200 outFrequency Range < 2:1 SWR (MHz): 1.8-61 MHz for 1.5KWPEP Power Rating (watts): 1.5KW/5KWInput Connector: UHF SO-239Output Connector(s): Side Eyeboplts (EB) or Top Studs (TS)Enclosure Size: 4"x4"x 2"(1.5KW), 4"x 4" x 4"(5KW)Weight (pounds): 2# (1.5KW), 4# (5KW)Antenna Compatability: OCF, Loop, BBTD, T2FD, ZEPP
After many requests we have created a compact, special balun for Off Center Fed (OCF) , loop (Skyloop or Delta loop) , BBTD, T2FD, folded dipoles antennas. The CB-4-1-1500 is a CUBE(TM) enclosure containing a multi-core, broadband 4:1 impedance transformer 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 1000 watts CW (ICAS). 1.8Mhz – 61 MHz.
CB-4-1-1500 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.
5KW are in 4" x 4" x 4" enclosure. 1.5KW is 2 pounds, 5KW is 4 pounds.
For an 80 meter OCF antennas we recommend a (95 feet/79.5% and 40 feet/29.5% offset for best all band results. If you use 66%/34% offset, do not use on 15 meters as the impedance mismatch may damage the balun at high power levels. 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 feet.
We highly recommend a feed line choke (MC-1-3000) or coax noise filter (CMNF-1500) at the radio end of the coax feed line to reduce common mode noise picked up by the coax braid.
CB-4-1-5000EB/TS are custom made to order - please allow 7-10 days ARO before ship.
Customer testimonial:
Callsign: NE5U Your CB-4-1500 +1:1 Choke made my homebrew, hail mary, 3 times folded 75m resonant attic dipole into a functional antenna from 6m to 160m. Most bands I can operate with no RFI. I've installed ferrites at all of the usual locations but still have some problem bands. Considering that the antenna is, at best, an NVIS antenna, I have made a lot of DX contacts (SSB, FT8 and other digital modes, and CW). Happy customer here. 73
After many requests we have created a compact, special balun for Off Center Fed (OCF) , loop (Skyloop or Delta loop) , BBTD, T2FD, folded dipoles antennas. The CB-4-1-1500 is a CUBE(TM) enclosure containing a multi-core, broadband 4:1 impedance transformer 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 1000 watts CW (ICAS). 1.8Mhz – 61 MHz.
CB-4-1-1500 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.
5KW are in 4" x 4" x 4" enclosure. 1.5KW is 2 pounds, 5KW is 4 pounds.
For an 80 meter OCF antennas we recommend a (95 feet/79.5% and 40 feet/29.5% offset for best all band results. If you use 66%/34% offset, do not use on 15 meters as the impedance mismatch may damage the balun at high power levels. 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 feet.
We highly recommend a feed line choke (MC-1-3000) or coax noise filter (CMNF-1500) at the radio end of the coax feed line to reduce common mode noise picked up by the coax braid.
CB-4-1-5000EB/TS are custom made to order - please allow 7-10 days ARO before ship.
Customer testimonial:
Callsign: NE5U Your CB-4-1500 +1:1 Choke made my homebrew, hail mary, 3 times folded 75m resonant attic dipole into a functional antenna from 6m to 160m. Most bands I can operate with no RFI. I've installed ferrites at all of the usual locations but still have some problem bands. Considering that the antenna is, at best, an NVIS antenna, I have made a lot of DX contacts (SSB, FT8 and other digital modes, and CW). Happy customer here. 73
TECH NOTE: We also stock RFI kits to protect effected devices such as garage door openers, computers (laptops, desktops), dsl/cable routers, ethernet hubs and many more devices. If you run a high powered RF amplifier in your ham station also consider a linear amp RFI kit which will cut down RFI transmitted by your station. Remember there is always a “transmitter” and a “receiver” of RFI and the quest is to find and choke the “path” the RFI has selected – you need to add ferrites to both the transmitting side and the receiving side to eliminate RFI problems. The RFI-HTS kit only helps suppress RFI on the receiving side.
Typical RFI Problem/Solution:
Hello, I am Larry, a ham operator and I am having interference issues with my Direct TV system. My station is a FT450D through an Ameritron ALS-600. From the amp through a coax switch to choose between an OCF dipole or an Hustler 5BTV vertical. Any power over 100 watts and my DTV goes off the air and must completly reboot/format. Coax is RG-8. The DTV dish is pointed away from the dipole and separated by about 25'. DTV was totally useless! They suggested I not talk on the radio while she is watching TV! Please help me with a reasonable, cost effective soultion. (The wife gets really pissed when I shutdown the tv!) Thank you, Larry
Hi Larry,
Your RFI problem is quite common and is usually a sign of either a radiating coax feed line or reception of your radiated signal (source) by the Direct TV (the victim) through either the AC power lines acting as “antennas” for your ham signal or the coax braid of the satellite antenna acting as an antenna for your signal.
The solutions are straight forward:
1. To make sure your feed line is not radiating you need a feed line choke at each antenna feed point (also makes your antenna work better since it is not using the coax as part of the antenna). You can use our simple Kit 110 with 5 snap on chokes on each antenna for this purpose. Part # Kit 110 at $27.50 each – one for each antenna. These chokes will keep your feed line from radiating and coupling into your ac power lines. INFO HERE
2. The radiation from your antennas themselves may also be getting into the ac power lines and coax braid of the Direct TV antenna so you need to protect the victim receiver. Depending upon the sophistication of your direct TV setup (e.g. home theater, dvd, tape player, sub woofer speakers, etc), the path of the RFI may be coming thru the AC power lines of any connected device to the video including the video monitor itself! To help solve this problem we have a home theater RFI kit for up to 5 devices (you need a minimum of two – one for the Direct TV receiver(AC and coax input) and another for the video monitor AC power lines and HDMI or video input cable. Our kit part # is RFI-HTS. INFO HERE
These items should help reduce the RFI and let you operate on the air while your wife watches TV.
Bob Brehm, AK6R
Chief Engineer