The ADALM Pluto software-defined radio is our runner up for best SDR. It’s an excellent platform for learning about SDR. By way of specifications, it provides frequency coverage between 325 MHz and 3800 MHz which covers most signals of interest.
ADALM Pluto is a transceiver. This means that it is capable of both transmitting and receiving signals.
For some applications you may want to amplify the transmitted signal such that it can reach further. As well, you may want to improve the sensitivity or the range of the receiver with the use of a low noise amplifier.
The good thing about the Plutosdr relative to other SDRs like HackRF is that it has separate transmit and receive ports. So as we discussed in this article you can add amplifiers to each port in order to accomplish this.
The question is what kind of amplifier should be used?
An amplifier used on a transmitter generally has different specifications relative to one that’s to be used on a receiver.
For a transmitter amplifier, the two most important parameters are:
- Gain – how much will the device amplify a signal at its input
- P1dB – this is a measure of how much output power the amplifier is capable of delivering
For a receiver amplifier, the two most important parameters are:
- Gain – how much will the device amplify a signal at its input
- Noise Figure – used to calculate how much the sensitivity of the receiver can be improved by
What’s the best transmitter amplifier for the Pluto SDR?
The maximum output power from the Pluto SDR transmitter is between +7 dBm and +8 dBm or about 5 mW. This transmitter amplifier will increase the transmit power to about +20 dBm or 100 mW.
Before you increase the amount of RF power you’re transmitting it’s important to check that you are legally allowed to do so. Many countries have restrictions on the amount of RF energy you can transmit in any band.
What’s the best receiver amplifier for the Pluto SDR?
The noise figure of the Pluto SDR is between 2.5 dB and 3.3 dB. In order to improve the sensitivity, this low noise amplifier can be used.
An important precaution is that the absolute maximum signal level at the input to the ADALM Pluto SDR is +2.5 dBm. Since the amplifier adds 17 dB of gain, it is important to ensure that the input signal does not exceed -15 dBm. It’s not often that signals of this amplitude are encountered in the real world unless you place the antenna right next to a wireless transmitter. However it’s very easy to exceed this level if you inject a signal from a signal generator into the amplifier.
Summary
In this article we have talked about two different LNAs that can be used with the ADALM Pluto Software-defined radio. These amplifiers can be used to enhance the performance of SDRs.