Coaxial Dynamics 81100-A – Precision Directional RF Wattmeter

Overview – Coaxial Dynamics 81100A

Coaxial Dynamics 81100A is a high-power directional RF wattmeter designed for 50-ohm 1-5/8 inch coaxial transmission lines at broadcast, telecom and industrial RF sites. It provides accurate forward and reflected power readings when used with the correct plug-in elements, making it ideal for monitoring high-power FM, VHF and UHF systems over a broad operating range. With its rugged metal housing, shock-mounted taut band meter movement and large mirrored scale, Coaxial Dynamics 81100A gives engineers a reliable, easy-to-read instrument that can live in the rack or travel in a field kit for many years.

Performance and key features

Coaxial Dynamics 81100A supports a wide power span, typically from a few hundred watts up to tens of kilowatts, depending on the selected plug-in element, so one meter can serve both medium-power and high-power transmitters. The 4-1/2 inch triple-scale meter face and taut band movement offer high readability and good accuracy, helping engineers spot even modest changes in forward or reflected power. A built-in 1-5/8 inch EIA flanged line section minimises insertion loss while maintaining a stable 50-ohm impedance, and the directional coupler arrangement allows quick selection of forward or reflected power with a simple element rotation. Gold-plated plug-in elements, quality connectors and a durable finish help Coaxial Dynamics 81100A maintain stable readings in demanding RF environments.

Applications and use cases

Coaxial Dynamics 81100A suits RF engineers who need dependable, high-power RF measurements in 1-5/8 inch transmission lines.

• Continuous monitoring of forward and reflected power on FM, VHF or UHF broadcast transmitters using 1-5/8 inch EIA rigid line.
• Commissioning and proof-of-performance tests on new transmitter plants, combiners and RF distribution networks.
• Routine maintenance, return-loss checks and troubleshooting of antennas, filters and dummy loads at elevated power levels.
• Portable RF test kits where a rugged, shock-resistant high-power directional wattmeter is required across multiple transmitter sites.

What’s included and integration

Coaxial Dynamics 81100A is supplied as a single-socket 1-5/8 inch EIA flanged line section with integrated directional coupler, large analogue meter and shock-mounted housing ready for rack or bench use. Plug-in elements, available in different frequency and power ranges, are ordered separately so engineers can configure the meter to match their specific band and power requirements. Integration into existing RF systems is straightforward: insert the unit in-line between the transmitter and antenna or dummy load, install the correct element and rotate it for forward or reflected readings. With a proven mechanical design and long service reputation, Coaxial Dynamics 81100A is a dependable choice for long-term RF power monitoring at high power levels.