Combining multiple UHF transmitters onto a single antenna
Tower owners and operators need to host multiple transmitters on one antenna without sacrificing transmit power or generating intermodulation products.
Why combiners exist
Every additional antenna on a tower costs leasing fees, wind load, and installation time. A combiner consolidates many radios onto one feedline at the cost of insertion loss — a tradeoff that is almost always worth it.
What to look for
A serious transmitter combiner has three properties: (1) per-port ferrite isolators that prevent reverse power from killing PAs, (2) per-port bandpass cavities that suppress harmonics and broadband noise, and (3) a calibrated sweep report from the manufacturer.
Recommended product
For 4-channel UHF combining at 380-470 MHz, the UHF 4-Channel Cavity Combiner (8-Inch) is the production-tested choice. For 8-channel high-density deployments, UHF 8-Channel Cavity Combiner (8-Inch). For broadband combining where channel spacing is tighter than cavity Q allows, the hybrid family — UHF 3-Channel Hybrid Combiner / UHF 4-Channel Hybrid Combiner — gives > 100 dB isolation across a 20 MHz window.
Recommended products
UHF 4-Channel Cavity Combiner (8-Inch)
380-470 MHz, 4 channels, 150 W/port, > 75 dB isolation, 3.4 dB IL @ ΔTx 450 kHz. 18U.
- Freq
- 380–470 MHz
- Power
- 15 W
- Isolation
- > 75 dB
UHF 8-Channel Cavity Combiner (8-Inch)
380-470 MHz, 8 channels, 150 W/port, > 75 dB isolation, 4.0 dB IL @ ΔTx 450 kHz. 36U.
- Freq
- 380–470 MHz
- Power
- 15 W
- Isolation
- > 75 dB
UHF 3-Channel Hybrid Combiner
380-470 MHz (5 sub-bands), 3 channels, 50 W/port, > 100 dB isolation, 6.2 dB IL. < 20 MHz spacing.
- Freq
- 380–470 MHz
- Power
- 5 W
- Isolation
- > 1 dB
UHF 4-Channel Hybrid Combiner
380-470 MHz (5 sub-bands), 4 channels, 50 W/port, > 100 dB isolation, 7.5 dB IL. < 20 MHz spacing.
- Freq
- 380–470 MHz
- Power
- 5 W
- Isolation
- > 1 dB
Field-deployed for this problem
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