Portable and Mobile Radio RFI Solutions
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.
Portable operation is typical of ham radio operating events such as Field Day, Summits on the Air, Route 66 events, National Parks on the Air, California QSO party, DXpeditions, and emergency operation command posts, etc.
Suggestions
Each low power operating station with a generator should have:
- Generator RFI Kit (Part # RFI-GEN) with FSB31-1 ferrite filters at each end + Nylon ties for security
- Transceiver RFI Kit (Part # RFI-XCVR)
- Laptop RFI Kit (Part # RFI-1C)
- Coax Cable Noise Filter (Part # CMNF-1)
- Bullet-55 portable HF end fed antenna system
4:1 impedance transformers (Baluns and Unun configurations) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call CUBE Baluns™ and CUBE Ununs™. All 4:1 impedance transformers use ferrite cores and the kit forms can be configured as a balun with balanced output of 200 ohms or as ununs with one side grounded.
4:1 baluns are designed for 50 ohm unbalanced (coax) input to 200 ohm output (either balanced or with one side grounded).
4:1 Baluns are useful between balanced lines for center fed Zepps, Off-center fed (OCF) dipoles with coax, G5RV antennas, full wave loops, NVIS dipoles that are close to ground and have impedance levels near 200 ohms or high impedance feeds for log periodic beams.
4:1 ununs are useful between coax and vertical antennas, monopole verticals or long wires with load impedances near 200 ohms.