SSB LNA-ISM-433 SMA low-noise preamplifier

Do you want to amplify weak signals within the 433 MHz ISM band before they reach your receiver? The SSB LNA-ISM-433 is a selective low noise pre-amplifier specifically developed for reception between 433 and 435 MHz. With a typical gain of 20 dB and a low noise figure of only 0.7 dB at 20 °C, this receive pre-amplifier is designed for applications where good signal amplification and the lowest possible noise addition are important.

But this LNA does more than just amplify. A high-quality bandpass filter at the output helps suppress signals outside the desired frequency range. This not only amplifies the desired signal but also reduces the burden on the downstream receiver from unwanted signals outside the used band.

That makes the SSB LNA-ISM-433 an interesting technical solution for various analog and digital communication applications within the 433 MHz ISM band.

What is a low noise pre-amplifier?

A low noise pre-amplifier, often abbreviated to LNA, is a low-noise pre-amplifier that amplifies a received RF signal before it is further processed by the receiver.

For weak signals, not only the amount of amplification is important. The amplifier itself should add as little additional noise to the signal as possible. Therefore, the noise figure is an important specification of an LNA.

The SSB LNA-ISM-433 has a specified noise figure of 0.7 dB at 20 °C and a typical gain of 20 dB. This makes this pre-amplifier specifically aimed at high-quality reception within its frequency range.

Specifically for the 433 MHz ISM band

This SSB pre-amplifier is not a general broadband amplifier. It is developed for the frequency range of 433 to 435 MHz.

This is an important advantage when signals within this frequency range are precisely what is interesting. At the output of the amplifier, there is a bandpass filter with high-quality components. This provides extra band selectivity and helps suppress strong, unwanted signals outside the usable band.

As a result, fewer unwanted signals reach the downstream receiver. The LNA-ISM-433 thus combines low-noise signal amplification with selective filtering.

GaAs MMIC technology and high-quality RF construction

SSB has used a GaAs MMIC on a high-quality microwave substrate board with SMD technology for the amplifier.

The input circuit is also explicitly focused on good noise characteristics. According to the manufacturer, high-quality components in a cell-design construction are used for this.

The input and output networks are designed for an impedance of 50 ohms with very small imaginary components. Together with a specified OIP3 of 32 dBm and IIP3 of 12 dBm, the amplifier is designed for both low noise and good large-signal behavior.

Power supply locally or via the coaxial cable

The SSB LNA-ISM-433 can be supplied with power in different ways.

You can connect a local power supply to the +12V DC connection. The allowed operating voltage is between 8 and 14V, and the specified current consumption is 110 mA.

Another option is power supply via the coaxial output cable using a suitable remote feeder, such as the SSB DCC 5000pro, which is placed before the receiver input.

When a suitable receiver itself provides the power supply for an LNA via the antenna connection, the coaxial output of the pre-amplifier can be connected directly to the antenna input of the receiver according to the instructions.

Use a good coaxial cable

With weak signals, you want to prevent some of the benefits of a low-noise pre-amplifier from being lost in the antenna cable. The manufacturer therefore advises using the shortest possible coaxial cable with low losses on the antenna side.

Examples given are Ecoflex 15, Aircom Premium, and Ecoflex 10. For the output cable, a thinner coaxial cable such as Aircell 7 can optionally be used, according to the instructions.

SSB also advises taking transforming cable lengths into account when determining the cable length. For this, the manufacturer provides the formula Lambda / 2 × N × V, where Lambda is the wavelength, N is a natural number, and V is the velocity factor of the coaxial cable used.

Important: for reception only

An important point to note about the SSB LNA-ISM-433 is that this pre-amplifier does not have automatic transmit/receive switching.

The LNA is intended as a receive pre-amplifier. Too high a signal level at the input or output can damage the device.

Therefore, do not simply use the amplifier in a signal path where a transmit signal may also be present. Carefully check how your complete antenna and receive configuration is set up and what signal levels may occur before installation.

Main features

• For 433 MHz ISM: selective receive pre-amplifier for 433 to 435 MHz.
  
• Low noise pre-amplifier: noise figure of 0.7 dB at 20 °C and typical gain of 20 dB.
  
• Selective filtering: bandpass filter helps suppress unwanted signals outside the usable band.
  
• High-quality RF technology: built around GaAs MMIC technology with a 50 ohm input and output.
  
• Flexible power supply: locally via the DC connection or, with a suitable installation, via the coaxial output line.

For serious 433 MHz reception

When working with weak signals, every component between the antenna and the receiver counts. A good low noise pre-amplifier should therefore not simply amplify as much as possible. Low inherent noise, selectivity, and good behavior with strong signals are at least as important.

Precisely that is what the SSB LNA-ISM-433 is aimed at. The combination of 20 dB typical gain, a noise figure of 0.7 dB, and filtering outside the desired band makes this LNA a specialized solution for high-quality reception between 433 and 435 MHz.

Do you want to get more out of a suitable receive installation for the 433 MHz ISM band? Choose the SSB LNA-ISM-433 and combine low-noise pre-amplification with selective filtering directly in your RF signal path.