The CU-49-2000 is a 49 Unun housed in a NEMA enclosure box (4″ x 4″ x 2″) with top coax connector output of 2450 ohms used to translate a 50 Ω unbalanced coax input to 2450 Ω unbalanced output at RF power levels up to 2000 watts PEP. With a matched 2450 ohm load the SWR over the frequency range 1.8-30 MHz is less than 3:1 on the coax input terminal.
High power, triple core design for long life, side vents for air circulation..
The GROUND terminal is connected to the 50 Ω INPUT connector shield.
Input connector is a SO-239.
Also includes ground lug/wingnut connected to input shield connector.
This unun is DC grounded.
Just add half wave of antenna wire at lowest frequency desired and work the multiples of half wave above that frequency.
This product supercedes CU-49-2000LF
Application Note: When using the CU-49-2000HF with an antenna, you should measure the SWRs on the harmonic bands which the antenna is designed for (e.g. a 135 foot, 80 meter EFHW works on 80-40-20-10 if cut for the lower end of 80 meters, 3.5MHz). When used on non-harmonic related bands to the 3.5Mhz fundamental, the antenna must have a SWR (taken at the antenna feed point, not the end of the radio coax) < 1.5:1 without an antenna tuner, to be used at powers over 500 watts or any mode or with a 50% duty cycle.
WARNING: There are many antenna configurations available on internet websites that say you can work non-harmonic bands with the use of an antenna tuner, but they forget to tell you that the unun will be over-taxed at low power levels since the impedance seen by the unun may not be close to 2450 ohms but may be very different. Using an antenna tuner only tunes the load seen at the antenna tuner end of the coax (e.g it only tunes the coax, not the antenna – the unun is still seeing an unmatched load and may easily saturate if too much power is fed to the unun). If the unun is used with an antenna tuner and an end fed wire antenna (130-135 feet in length), power should be reduced on those bands that show an SWR above 1.5:1 SWR, at the antenna feed point, without the tuner. If your antenna shows a SWR of 3:1 on any band, you should restrict the power level and/or duty cycle down to a level which doesn’t saturate the unun.The power input level will depend on band, mode and antenna design.
This product is no longer in production as the EFHW antenna has been replaced with the far superior end fed OCF antenna which is shorter in length AND does cover all the WARC bands AND has no dangerous high voltage at the unun.
Generator RFI testimonial:
Bob Received your order in a timely fashion. Tried the generator kit on Sunday & it drops the noise from S9 to S5 and took out all the electrical noise. I may want some more toroids from you at some point for other interference problems I have here. Ken VE3KCY
Using an amplifier? Don’t forget our Linear Amplifier RFI Kits
Want to make up your own RFI kits for a particular operation? Here are links to some of typical RFI solutions used in portable operations:
If you use a computer for logging in your portable operations, RFI getting into computers will often lock up your computer and/or radio and a computer RFI suppression kits may be helpful
Make your expedition or portable operation a pleasant and fun outing and remember to take along your RFI kits so you have more time to operate rather then to troubleshoot intermittent or noisy receiver conditions.
Portable Antenna Kits
If you need an effective portable antenna which folds up for transport yet is easy to deploy at your operating site, consider the BULLET series of end fed wire antennas.
BULLET Antennas (click on link or picture for more info)
