Monthly Archives: November 2024

When it comes to satellite communication, the choice between a Phase-Locked Loop (PLL) and a Dielectric Resonator Oscillator (DRO) Low Noise Block (LNB) can have a significant impact on signal quality and reception. 

 

Understanding the Basics

The LNB is a critical component in satellite reception systems, responsible for converting the high-frequency satellite signal into a lower frequency that can be processed by the satellite receiver. The L.O. (Local Oscillator) frequency generated by the LNB is the key to this conversion process. PLL and DRO are two different techniques used to generate this frequency.

 

PLL vs. DRO: A Technical Breakdown

Feature	PLL	DRO
Oscillator Type	Phase-Locked Loop	Dielectric Resonator Oscillator
Stability	High (±500 kHz to ±25 kHz)	Low (±1 MHz to ±3 MHz)
Temperature Sensitivity	Low	High
Cost	Higher	Lower

A PLL oscillator uses a more accurate reference clock and a feedback circuit to maintain a stable output frequency, while a DRO is a simpler and less expensive device that relies on a ceramic disc to resonate at a specific frequency. The tradeoff is that PLL LNBs offer superior stability and accuracy.

 

When to Choose PLL or DRO LNB

The choice between a PLL or DRO LNB depends on the specific needs of your satellite reception setup and the type of signals you’re trying to receive.

DRO LNB: Best for Strong, Stable Signals

• DRO LNBs are well-suited for receiving powerful, “fat” DVB-S MPEG-2 signals, such as those found on 97W/Galaxy 19.
• These signals are already strong and don’t require a high degree of frequency accuracy for decent reception.
• DRO LNBs are often used in more affordable satellite systems or dedicated setups for religious/ethnic programming (Allseeing Technology, 2019).

 

PLL LNB: Excelling at Weak and DVB-S2 Signals

• PLL LNBs are the preferred choice for enthusiasts and commercial users who need to receive weaker signals, DVB-S2 transmissions, and signals with high Forward Error Correction (FEC).
• The superior stability and accuracy of PLL oscillators allow them to “thread the needle” and lock onto these challenging signals much more effectively than DRO LNBs.
• PLL LNBs can also provide higher signal strength, better rain fade resistance, and the ability to receive more channels, including those that may be out of reach for DRO-based systems (Allseeing Technology, 2019).

 

The Rise of Affordable PLL LNBs

Until recently, PLL LNBs were primarily used in high-end commercial and enthusiast-level satellite systems due to their higher cost. However, a recent technological advancement has led to the development of a single-IC Ku-band PLL oscillator, enabling manufacturers to offer PLL LNBs at more affordable prices (Allseeing Technology, 2019).

This breakthrough has been a game-changer, allowing everyday satellite enthusiasts to benefit from the superior performance of PLL technology without breaking the bank. As more manufacturers adopt this new PLL IC, the availability and affordability of PLL LNBs are expected to continue improving.

 

Key Features at a Glance

• PLL LNBs offer significantly better stability and accuracy than DRO LNBs, especially for weak and DVB-S2 signals.
• DRO LNBs are suitable for strong, stable signals like those found on 97W/Galaxy 19, but may struggle with more challenging transmissions.
• Affordable PLL LNBs are now available thanks to a new single-IC Ku-band PLL oscillator, making this advanced technology accessible to a wider audience.
• The choice between PLL and DRO LNBs depends on the specific requirements of your satellite reception setup and the type of signals you need to receive.

 

 

 

 

Source:
Allseeing Technology. (2019). PLL vs DRO LNB – Which is better?