Protecting transmitter PA stages from reflected power and inter-system intermod
A failed antenna, a wet feedline connector, or a strong nearby transmitter can drive reflected power back into the PA — and at multi-carrier sites, two transmitters mixing in a non-linear element generate intermod products that fall back into your receiver band.
The two failure modes
Reflected power: SWR climbs above 2:1 and the PA's reverse-power protection trips, or worse, fails open. A ferrite isolator absorbs reflected power into a load, decoupling the PA from antenna-side faults.
Inter-system intermod: when a strong second carrier reaches your transmitter's output stage, the non-linearity generates IM products that fall in-band at nearby receivers. The isolator presents > 75 dB of reverse isolation, suppressing the second carrier before it reaches your PA.
Recommended product
For UHF systems, Dual Isolator UHF 380-470 MHz. For VHF, Dual Isolator VHF 145-175 MHz. For airband, Dual Isolator AIRB 112-136 MHz. All three share the same dual-stage construction and temperature-stability curve — pick by band.
Recommended products
Dual Isolator UHF 380-470 MHz
380-470 MHz, 150 W max power, >75 dB typical isolation, <1.0 dB insertion loss.
- Freq
- 380-470 MHz
- Power
- 15 W
- Isolation
- > 75 dB
Dual Isolator VHF 145-175 MHz
145-175 MHz, 150 W max power, >75 dB typical isolation, <1.0 dB insertion loss.
- Freq
- 145-175 MHz
- Power
- 15 W
- Isolation
- > 75 dB
Dual Isolator AIRB 112-136 MHz
112-136 MHz, 150 W max power, >75 dB typical isolation, <1.0 dB insertion loss.
- Freq
- 112-136 MHz
- Power
- 15 W
- Isolation
- > 75 dB
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