Good news for amateur radio operators using the Icom IC-905 10 GHz system!
Following feedback from the San Bernardino Microwave Society (SBMS), Gordon West WB6NOA, and other users, Icom America has agreed to address the polarization configuration issue that’s been affecting signal performance.
The issue: The IC-905’s dish antenna comes configured for vertical polarization. Vertical polarization is standard in Japan. However, most U.S. amateur microwave operations use horizontal polarization.
This mismatch has resulted in significant signal strength differences during contacts.
The solution is simple: rotate either the entire dish or just the feed horn 90 degrees to achieve horizontal polarization. However, many operators weren’t aware of this requirement.
Ray Novak (N9JA) from Icom America has committed to updating the product instructions and adding a label to the packaging that alerts customers about the dish’s default vertical polarization and how to configure it for horizontal operation.
Icom has also expressed willingness to work with SBMS on developing educational content about this issue, potentially including information about SBMS membership.
Amateur radio groups interested in contributing to this effort should contact Ray Novak directly at
raynovak@icomamerica.com.
This collaborative approach between manufacturers and the amateur radio community demonstrates how user feedback can lead to improved documentation and better user experiences for microwave enthusiasts.
Below is a diagram showing the 90 degree relationship between horizontal and vertical polarization. Rotating the dish or feed by 90 degrees restores the 20-30 dB loss that you will get if your equipment is cross-polarized.
