PLH-3500
Power Line Carrier Hybrid
A power line carrier hybrid for coupling transmitter and receiver equipment to high-voltage transmission lines. Supports up to four configurable hybrid slots in any combination of skewed and balanced, all in a compact, 1U rack-mountable form factor.
Insertion loss (skewed / balanced)
0.5 / 3.0 dB
Form factor
1U rack-mount
Transhybrid loss
> 50 dB
Power Line Carrier Hybrid Networks
A hybrid is a bridge network used to combine and separate transmitter and receiver signals on a shared power line carrier path. The PLH‑3500 includes two primary hybrid types, balanced and skewed, each optimized for different roles in the signal chain.
Low‑Loss Transmitter Path
The skewed hybrid is designed for bi‑directional applications, combining transmitters and receivers on a single line connection. It delivers less than 1 dB of insertion loss in the transmitter path, compared with 3.5 dB in resistive or reactive type hybrids, helping overcome power line noise. This low insertion loss comes at the expense of added attenuation (approximately 12–13 dB) in the receive port; however, both signal and noise are attenuated equally, so receiver performance is unaffected.
The skewing action is achieved using two transformers for balancing. A skewed hybrid should be used as the first hybrid in a chain, with all receivers daisy‑chained off the receiver port. The receiver port must be terminated in 50 ohms.
Precision Signal Splitting
The balanced hybrid consists of an accurately mid‑tapped transformer and a balance resistor, designed so that a signal applied to either input terminal produces minimal signal voltage at the opposite input. In a typical balanced hybrid, the signal attenuation between inputs is around −30 dB, known as the transhybrid loss. The PowerComm Solutions PLH‑3500 achieves transhybrid loss greater than 50 dB, far exceeding industry norms.
This balancing transformer is also used to split the carrier signal at the line tuner, with the same circuit serving dual roles depending on how the inputs and outputs are configured.
| Skewed Hybrid | |
|---|---|
| Frequency range | 30 kHz to 600 kHz |
| Max power | 100 Watts |
| TX port | BNC into 50 Ω system |
| RX port | BNC 50 Ω / HI Z |
| Line port | BNC 50 Ω connected to transmission line |
| Insertion loss (TX to Line) | 0.5 dB |
| Insertion loss (Line to RX, 50 Ω jumper selected) | 12.5 dB |
| Transhybrid loss | > 50 dB |
| Balanced Hybrid | |
| Frequency range | 30 kHz to 600 kHz |
| Max power | 25 Watts |
| IN 1 port | BNC into 50 Ω system |
| IN 2 port | BNC into 50 Ω system |
| Line port | BNC 50 Ω connected to transmission line |
| Insertion loss (IN 1 to Line) | 3.0 dB |
| Insertion loss (IN 2 to Line) | 3.0 dB |
| Insertion loss (Line to IN 1 & IN 2) | 3.0 dB |
| Transhybrid loss | > 50 dB |
| Physical | |
| Dimensions (W × H × D) | 19.0 × 3.5 × 12.0 in |
| Weight | 13.21 lbs |
| Mounting | Standard 19" rack, 2U |
| Environmental | |
| Operating temperature | -30°C to +70°C (ANSI C37.90) |
| Humidity | Up to 95% non-condensing at 40°C for 96 hrs cumulative (ANSI C93.5) |