Portable Operation RFI Kits

50:200 (4:1) CUBE™ Unun, 1.8-61 MHz, 1500/5000 Watts PEP, End Fed, Vertical, Monopole

SKU CU-4-1500
$109.95
Bulk pricing available for quantities of 2 units or more
Power Rating (PEP)
1
Buy more, save more
QuantityPrice per itemDiscount
2 items$99.959% off
10 items$94.9514% off
50 items$89.9518% off
100 items$79.9527% off
Save this product for later
Customer reviews
No reviews yet. Only signed-in customers who bought this product can leave reviews. To leave a review, sign in
Share this product with your friends
50:200 (4:1) CUBE™ Unun, 1.8-61 MHz, 1500/5000 Watts PEP, End Fed, Vertical, Monopole
Product Details
Input ohms/Output ohms: 50/100-400
Frequency Range < 2:1 SWR (MHz): 1.8-61 (1.5KW), 1.8-31 MHZ for 5000/5000HD
PEP Power Rating (watts): 1500/5000
Insertion Loss (dB): .15
Input Connector: SO-239
Output Connector(s): Wingnut/Eyebolt
Transformer Topology: Broadband Ferrite
Hardware Type: Stainless
Enclosure Size: 4" x 4" x 2"
Antenna Compatability: verticals, slopers, monopoles

Purpose. The CU-4-1500 is used as a 4:1 (200 ohm unbalanced load to 50 ohm unbalanced source) broadband transformer for 50 ohm coax cable rated at at 1500 PEP into 200 ohms unbalanced load from 1.8-61 MHz. Excellent for 43 foot verticals and also slopers (51', 85' or 119" work great)

USE: The top connector is for the 200 ohm unbalanced output, and the side connector is for a ground rod or radial connection.The SO-239 input connector shield/ground is shared with the ground connector.


For best results use a feed line choke between the CU-4-1500 and the coax input to isolate the coax from becoming part of the antenna. Our Maxi-Choker (MC-1-3000) is an excellent companion for this unun.

This Unun is a very efficient match for many 43 and 31-33 foot multi-band verticals including the S9, ZeroFive, MFJ and DX Engineering vertical antennas.

The CU-4-1500 is also useful for end fed OCF antennas utilizing a 4:1 unun and a coax feed line choke to set the antenna length for the "short" side of the OCF.

CU-4-5000 is in a 4" x 4" x 2" NEMA enclosure and weighs 3 pounds and is specified for 1.8-31 MHz - rated at 5KW PEP

CU-4-5000HD is in a 4" x 4" x 4" NEMA enclosure, contains 50% more ferrite cores then the 5000 and weighs 4 pounds and is specified for 1.8-31 MHz - rated at 4KW continuous duty, 5K+ PEP. The HD version of this unun is CUSTOM MADE PER ORDER - PLEASE ALLOW 2 WEEKS FOR MANUFACTURING PRIOR TO SHIPMENT.

Portable operation is fun but also brings challenges to the radio operator concerning receiver “noise” levels, RF interference from adjacent sources including close by transmitting stations, and RFI from portable generators.  A typical scenario and some suggested Palomar product solutions are shown in the picture below:

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:

AC/DC common mode filters

Feed Line chokes

Coax Noise Filters

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

Computer RFI Kits

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)

Bullet Antenna Product 300x292 - Portable Operation RFI Kits