Tagged: LNA

New Product: RTL-SDR Blog 1090 MHz ADS-B LNA

We're happy to announce the release of our new high performance low noise amplifier (LNA) for improving 1090 MHz ADS-B reception. The LNA uses a low noise figure high linearity two stage MGA-13116 amplifier chip and three stages of filtering to ensure that strong signals or interference will not overload either the amplifier or SDR dongle.

The LNA is currently only available from our Chinese warehouse, and costs US$24.95 including shipping. Please note that the price may increase slightly in the future, and that Amazon USA may not be stocked until March.

Click here to visit our store

RTLBlog_LNA_Product_Flat
RTLBlog_LNA_Product_PCB_Flat

An LNA can help improve ADS-B reception by reducing the noise figure of the system and by helping to overcome losses in the coax cable and/or any other components such as switches and connector in the signal path. To get the best performance from an LNA, the LNA needs to be positioned close to the antenna, before the coax to the radio.

The gain of the RTL-SDR Blog ADS-B LNA is 27 dB's at 1090 MHz, and out of band signals are reduced by at least 60 - 80 dB's. Attenuation in the broadcast FM band and below 800 MHz is actually closer to over 100 dB's. In the LNA signal path there is first a low insertion loss high pass filter that reduces the strength of any broadcast FM, TV, pager or other similar signals that are usually extremely strong. Then in between the first and second stage of the LNA is a SAW filter tuned for 1090 MHz. A second SAW filter sits on the output of the LNA. The result is that strong out of band signals are significantly blocked, yet the LNA remains effective at 1090 MHz with a low ~1 dB noise figure.

The LNA is also protected against ESD damage with a gas discharge tube and low capacitance ESD diode. But please always remember that your antenna must also be properly grounded to prevent ESD damage.

Finally please note that this LNA requires bias tee power to work. Bias tee power is when the DC power comes through the coax cable. The RTL-SDR V3 has bias tee power built into it and this can be activated in software. See the V3 users guide for information on how to activate it. Alternatively if you don't own a dongle with bias tee built in, then an external bias tee can be used and those can be found fairly cheaply on eBay. Finally, if you are confident with soldering SMT components, then there are also pads and a 0 Ohm resistor slot on the PCB to install an LDO and power the LNA directly.

Specification Summary:

  • Frequency: 1090 MHz
  • Gain: 27 dB @ 1090 MHz
  • Return Loss: -16 dB @ 1090 MHz (SWR = 1.377)
  • Noise Figure: ~1 dB
  • Out of band attenuation: More than 60 dB
  • ESD Protection: Dual with GDT and ESD Diode
  • Power: 3.3 - 5V via bias tee only, 150 mA current draw
  • Enclosure: Aluminum enclosure
  • Connectors: Two SMA Female (Male to Male adapter included)

Dimensions:

46.5 x 32 x 15.6 mm (not including the SMA).
Including the SMA the length is 69.8 mm.

Testing

We tested our new LNA against another ADS-B LNA with filter built in that is sold by another company and the FlightAware Prostick+ dongle in an environment with strong out of band signals such as pagers, broadcast FM, DVB-T and GSM signals. The results showed that the RTL-SDR Blog ADS-B LNA gathered the most ADS-B packets. In the tests both LNA's were connected on the receiver side to be fair to the FA dongle. Improved performance could be achieved by moving the LNA to the antenna side.

Other ADS-B LNA vs RTL-SDR Blog ADS-B LNA Received Messages
FlightAware Prostick+ vs RTL-SDR Blog ADS-B LNA Received Messages

Checking in SDR# for out of band signals also showed that the RTL-SDR Blog ADS-B LNA significantly reduces those strong out of band signals, whereas the others have trouble blocking them out. Below we show the results as well as some measurements.

RTL Blog ADS-B LNA @ 1090 MHz

RTL Blog ADS-B LNA @ 1090 MHz

Other ADS-B LNA @ 1090 MHz

Other ADS-B LNA @ 1090 MHz

FlightAware Prostick+ @ 1090 MHz

FlightAware Prostick+ @ 1090 MHz

RTL Blog ADS-B LNA tuned to Broadcast FM

RTL Blog ADS-B LNA tuned to Broadcast FM

Other ADS-B LNA tuned to Broadcast FM

Other ADS-B LNA tuned to Broadcast FM

FlightAware Protstick+ tuned to Broadcast FM

FlightAware Protstick+ tuned to Broadcast FM

RTL Blog ADS-B LNA tuned to a DVB-T Signal

RTL Blog ADS-B LNA tuned to a DVB-T Signal

Other ADS-B LNA tuned to a DVB-T Signal

Other ADS-B LNA tuned to a DVB-T Signal

FlightAware Prostick+ tuned to a DVB-T Signal

FlightAware Prostick+ tuned to a DVB-T Signal

RTL Blog ADS-B LNA tuned to a GSM Signal

RTL Blog ADS-B LNA tuned to a GSM Signal

Other ADS-B LNA tuned to a GSM Signal

Other ADS-B LNA tuned to a GSM Signal

FlightAware Prostick+ tuned to a GSM Signal

FlightAware Prostick+ tuned to a GSM Signal

Gain Measurements

Gain Measurements

Return Loss

Return Loss

Simulated Gain/Attenuation

Simulated Gain/Attenuation

Conclusion

This RTL-SDR Blog ADS-B LNA can significantly improve ADS-B reception, especially if you are in an environment with strong out of band signals. Even if you are not, the low noise figure design will improve reception regardless.

New Product: RTL-SDR Blog 1090 MHz ADS-B LNA

We're happy to announce the release of our new high performance low noise amplifier (LNA) for improving 1090 MHz ADS-B reception. The LNA uses a low noise figure high linearity two stage MGA-13116 amplifier chip and three stages of filtering to ensure that strong signals or interference will not overload either the amplifier or SDR dongle.

The LNA is currently only available from our Chinese warehouse, and costs US$24.95 including shipping. Please note that the price may increase slightly in the future, and that Amazon USA may not be stocked until March.

Click here to visit our store

RTLBlog_LNA_Product_Flat
RTLBlog_LNA_Product_PCB_Flat

An LNA can help improve ADS-B reception by reducing the noise figure of the system and by helping to overcome losses in the coax cable and/or any other components such as switches and connector in the signal path. To get the best performance from an LNA, the LNA needs to be positioned close to the antenna, before the coax to the radio.

The gain of the RTL-SDR Blog ADS-B LNA is 27 dB's at 1090 MHz, and out of band signals are reduced by at least 60 - 80 dB's. Attenuation in the broadcast FM band and below 800 MHz is actually closer to over 100 dB's. In the LNA signal path there is first a low insertion loss high pass filter that reduces the strength of any broadcast FM, TV, pager or other similar signals that are usually extremely strong. Then in between the first and second stage of the LNA is a SAW filter tuned for 1090 MHz. A second SAW filter sits on the output of the LNA. The result is that strong out of band signals are significantly blocked, yet the LNA remains effective at 1090 MHz with a low ~1 dB noise figure.

The LNA is also protected against ESD damage with a gas discharge tube and low capacitance ESD diode. But please always remember that your antenna must also be properly grounded to prevent ESD damage.

Finally please note that this LNA requires bias tee power to work. Bias tee power is when the DC power comes through the coax cable. The RTL-SDR V3 has bias tee power built into it and this can be activated in software. See the V3 users guide for information on how to activate it. Alternatively if you don't own a dongle with bias tee built in, then an external bias tee can be used and those can be found fairly cheaply on eBay. Finally, if you are confident with soldering SMT components, then there are also pads and a 0 Ohm resistor slot on the PCB to install an LDO and power the LNA directly.

Specification Summary:

  • Frequency: 1090 MHz
  • Gain: 27 dB @ 1090 MHz
  • Return Loss: -16 dB @ 1090 MHz (SWR = 1.377)
  • Noise Figure: ~1 dB
  • Out of band attenuation: More than 60 dB
  • ESD Protection: Dual with GDT and ESD Diode
  • Power: 3.3 - 5V via bias tee only, 150 mA current draw
  • Enclosure: Aluminum enclosure
  • Connectors: Two SMA Female (Male to Male adapter included)

Dimensions:

46.5 x 32 x 15.6 mm (not including the SMA).
Including the SMA the length is 69.8 mm.

Testing

We tested our new LNA against another ADS-B LNA with filter built in that is sold by another company and the FlightAware Prostick+ dongle in an environment with strong out of band signals such as pagers, broadcast FM, DVB-T and GSM signals. The results showed that the RTL-SDR Blog ADS-B LNA gathered the most ADS-B packets. In the tests both LNA's were connected on the receiver side to be fair to the FA dongle. Improved performance could be achieved by moving the LNA to the antenna side.

Other ADS-B LNA vs RTL-SDR Blog ADS-B LNA Received Messages
FlightAware Prostick+ vs RTL-SDR Blog ADS-B LNA Received Messages

Checking in SDR# for out of band signals also showed that the RTL-SDR Blog ADS-B LNA significantly reduces those strong out of band signals, whereas the others have trouble blocking them out. Below we show the results as well as some measurements.

RTL Blog ADS-B LNA @ 1090 MHz

RTL Blog ADS-B LNA @ 1090 MHz

Other ADS-B LNA @ 1090 MHz

Other ADS-B LNA @ 1090 MHz

FlightAware Prostick+ @ 1090 MHz

FlightAware Prostick+ @ 1090 MHz

RTL Blog ADS-B LNA tuned to Broadcast FM

RTL Blog ADS-B LNA tuned to Broadcast FM

Other ADS-B LNA tuned to Broadcast FM

Other ADS-B LNA tuned to Broadcast FM

FlightAware Protstick+ tuned to Broadcast FM

FlightAware Protstick+ tuned to Broadcast FM

RTL Blog ADS-B LNA tuned to a DVB-T Signal

RTL Blog ADS-B LNA tuned to a DVB-T Signal

Other ADS-B LNA tuned to a DVB-T Signal

Other ADS-B LNA tuned to a DVB-T Signal

FlightAware Prostick+ tuned to a DVB-T Signal

FlightAware Prostick+ tuned to a DVB-T Signal

RTL Blog ADS-B LNA tuned to a GSM Signal

RTL Blog ADS-B LNA tuned to a GSM Signal

Other ADS-B LNA tuned to a GSM Signal

Other ADS-B LNA tuned to a GSM Signal

FlightAware Prostick+ tuned to a GSM Signal

FlightAware Prostick+ tuned to a GSM Signal

Gain Measurements

Gain Measurements

Return Loss

Return Loss

Simulated Gain/Attenuation

Simulated Gain/Attenuation

Conclusion

This RTL-SDR Blog ADS-B LNA can significantly improve ADS-B reception, especially if you are in an environment with strong out of band signals. Even if you are not, the low noise figure design will improve reception regardless.

How an LNA can Improve VHF Reception with an RTL-SDR

Over on his YouTube channel Adam 9A4QV has uploaded a video showing how an LNA work to improve signal SNR on VHF, as long as the LNA is placed close to the antenna. Adam is the manufacturer and seller of the popular LNA4ALL low noise amplifiers.

On UHF and high frequencies an LNA can help by reducing the system noise figure, but on VHF this effect is small. But if the LNA is placed near the antenna then the LNA can still help significantly by overcoming any losses in the coax cable, filters, switches or any other lossy components in the signal path. It might also help create a better SWR match for the dongle and antenna. The video has some sound issues in during the demonstration part, but on his Reddit thread Adam writes:

Well, monitoring the beacon signal on 144.478 Mhz the S/n without LNA was just 10dB and cannot improve with decreasing the gain. Inserting the LNA in line, close to the antenna, through the Bias-T the S/n improve from 10dB to 23dB.

To meet the most of the user's conditions I was using the RTL-SDR dongle and the 20 meters of RG-6 coaxial cable with F-connectors.

It is obvious that using the LNA on the antenna can improve your reception even on the VHF band. Using the proper bandpass filter instead of a single FM stop filter will give much better results.

Comparing Two LNA’s for HRIT/LRIT (GOES) Reception

Over on his blog Lucas Teske has been comparing the LNA4ALL and an SPF5189 LNA from eBay on HRIT/LRIT reception from GOES satellites. SPF5189 LNA’s can be found on eBay for less than $8 USD, with free shipping from China, whereas the LNA4ALL costs 27 Euros shipped from Croatia. GOES is a geosynchronous orbit weather satellite which requires a satellite dish or other high gain antenna to receive. It downlinks at about 1.7 GHz, which means that a high quality LNA with low noise figure and good PCB design is needed for reception.

In his post Lucas mentions how he saw a review on eBay stating that the SPF5189 did not work at L-band. However, he found that odd as all of his SPF5189 LNA’s seemed to work just fine with L-band reception. So he did a benchmark comparing the SPF5189 to the PSA5043+ based LNA4ALL which is known to work well on L-band.

From his comparisons he found that the SPF5189 does indeed work well on L-band, and is comparable to the LNA4ALL. He concludes that the reviewer must have received a bad unit, or didn’t know what he was doing.

Lucas also makes an important note regarding the PCB design of these LNA’s. Even though the SPF5189 and PSA5043 chips have similar specs, with LNA’s the design of the PCB is crucial, as a poor design can significantly degrade performance. With the LNA4ALL you can be sure that the design is good, although the SPF5189 LNA’s currently on eBay look to be designed okay as well. Though with some eBay sellers there is no guarantee that you will receive a good board. We note that we have seen some really poor designs for PSA5043 LNA’s out there as well.

The eBay SPF5189 LNA vs the LNA4ALL from 9A4QV
The eBay SPF5189 LNA vs the LNA4ALL from 9A4QV

Radio For Everyone New Posts: Line of Sight, Why USB Cable Quality Matters, Uputronics 1090 MHz Filtered Preamp Review

Over on his radioforeveryone.com blog, author Akos has uploaded three new posts. The first post briefly explains visually what is meant by line of sight when it comes to radio signals. Essentially at UHF and higher frequencies the radio antenna needs to be able to ‘see’ the transmitter, meaning that any blockages such as trees, houses etc will block the signal.

In his second post Akos briefly explains why USB cable quality can matter when it comes to SDRs. He shows that some USB cables tend to pick up more interference than others. 

Finally in his third post Akos reviews the Uputronics 1090 MHz Filtered Preamp. Uputronics is a UK based company that sells various filtered LNA’s. Akos writes how he’s very impressed with the premium packaging, look and feel of the device and thickness of the metal case. In performance tests the preamp together with a V3 dongle with bias tee power clearly improves ADS-B position reports significantly. We note that we also have 1090 MHz filtered preamp from Uputronics (an older model), and can also highly recommend their products.

The Uputronics 1090 MHz Filtered Preamp reviewed on radioforeveryone.
The Uputronics 1090 MHz Filtered Preamp reviewed on radioforeveryone.com

FlightAware Release their Pro Stick Plus: An ADS-B Optimized RTL-SDR with LNA and 1090 MHz Filter Built in

Back in March of this year we posted about the release of the FlightAware “Pro Stick”. The Pro Stick is FlightAware’s ADS-B optimized RTL-SDR dongle. It uses a low noise figure LNA on the RF front end to reduce the system noise figure, thus improving the SNR at 1090 MHz. Because the added gain of the LNA can easily cause overload problems if there are other strong signals around, FlightAware recommend using one of their 1090 MHz ADS-B filters in front of the dongle to prevent overload.

FlightAware have just come out with the “Pro Stick Plus” which is the same as their Pro Stick, but now with the 1090 MHz filter built into the dongle itself. The Pro Stick Plus costs $20.95 USD on Amazon, which is a good deal cheaper than buying the standard Pro Stick ($16.95 USD) plus their ADS-B filter ($19.95 USD), which totals $36.90. Customers outside of the USA can purchase the Pro Stick Plus from seller WiFi Expert on eBay for $29.95 USD.

FlightAware.com is a company that specializes in live air travel tracking. Most of their data comes from volunteers running RTL-SDR ADS-B receivers.

The new Pro Stick Plus RTL-SDR based ADS-B Receiver from FlightAware.
The new Pro Stick Plus RTL-SDR based ADS-B Receiver from FlightAware.

Over on their forums and on Amazon, they announced the device and specs. They wrote:

FlightAware is excited to announce the next evolution of USB SDR sticks for ADS-B reception! The new Pro Stick Plus USB SDR builds on the popular Pro Stick by adding a built-in 1090 MHz bandpass filter. The built-in filter allows for increased performance and range of reception by 10-20% for installations where filtering is beneficial. Areas with moderate RF noise, as is typically experienced in most urban areas, generally benefit from filtering. By integrating the filter into the SDR stick, we are able to reduce the total cost by more than 40% when compared to buying a Pro Stick and an external filter.

Specifications:

  • Filter: 1,075 MHz to 1,105 MHz pass band with insertion loss of 2.3 dB; 30 dB attenuation on other frequencies
  • Amp: 19 dB Integrated Amplifier which can increase your ADS-B range 20-100% more compared to dongles from other vendors which can increase range 10-20% over a Pro Stick in environments where filtering is beneficial
  • Native SMA connector
  • Supported by PiAware
  • R820T2 RTL2832U chips
  • USB powered, 5V @ 300mA

Note that this dongle is only for ADS-B at 1090 MHz, and not for 978 MHz UAT signals, as the filter will cut that frequency out.

Back in April, we did a review of the original Pro Stick. We found its performance on ADS-B reception to be excellent, but only when a filter was used. The low NF LNA theoretically improves the SNR of ADS-B signals by about 7-8 dB, but in reality there is too much gain causing signal overload everywhere, thus making reception impossible without the filter. Rural environments may not need a filter, but in a typical urban or city environment strong FM/TV/GSM/etc signals are abundant and these signals easily overloaded the Pro Stick when no filtering was used. This new Pro Stick Plus dongle completely solves that problem at a low cost with its built in filter.

Remember that if you are using a run of coax cable between the LNA and RTL-SDR, then it is more optimal to use an external LNA, like the LNA4ALL. Only an external LNA mounted near the antenna can help overcome coax, connector, filter and other losses as well as reducing the system noise figure. The FlightAware dongles are the optimal solution when they are mounted as close to the antenna as possible. This is usually the case when running the FlightAware feeder software on a Raspberry Pi.

We hope to soon review the Pro Stick Plus, however we assume it will operate nearly identically to the Pro Stick + FlightAware ADS-B filter combination.

Review: Outernet LNA and Patch Antenna

Recently we posted news that Outernet had released their 1.5 GHz LNA, Patch Antenna and E4000 Elonics RTL-SDR + E4000/LNA Bundle. When used together, the products can be used to receive the Outernet L-band satellite signal, as well as other decodable L-band satellite signals like AERO and Inmarsat STD-C EGC. Outernet is a new satellite service that aims to be a free “library in the sky”. They continuously broadcast services such as news, weather, videos and other files from satellites.

EDIT: For international buyers the Outernet store has now started selling these products at http://store.outernet.is.

A few days ago we received the LNA and patch antenna for review. The patch antenna is similar to the one we received a while ago when writing our STD-C EGC tutorial, although this one is now slightly larger. It is roughly 12 x 12 cm in size, 100g heavy and comes with about 13 cm of high quality RG316 coax cable with a right angled SMA male connector on the end. The coax cable is clamped on the back for effective strain relief.

The Outernet patch antenna and LNA
The Outernet patch antenna and LNA

The LNA is manufactured by NooElec for Outernet. It amplifies with 34 dB gain from 1525 – 1559 MHz, with its center frequency at 1542 MHz. It must be powered via a 3 – 5.5V bias tee and draws 25 mA. The package consists of a 5 x 2.5 cm PCB board with one female and one male SMA connector. The components are protected by a shielding can. Inside the shielding can we see a MAX12000 LNA chip along with a TA1405A SAW filter. The MAX12000 (datasheet here) is an LNA designed for GPS applications and has a NF of 1 dB. It has a design where there are two amplifiers embedded within the chip, and it allows you to connect a SAW filter in between them. The TA1405A SAW filter appears to be produced by Golledge (datasheet here), and it has about a 3 dB insertion loss.

The Outernet L-Band LNA
The Outernet L-Band LNA
Inside the Outernet LNA
Inside the Outernet LNA

We tested the patch and LNA together with one of our V3 RTL-SDR Blog dongles, with the bias tee turned on. The LNA was connected directly to the dongle, with no coax in between. The patch antenna was angled to point towards the Inmarsat satellite. A 5 meter USB extension cord was then used to interface with a PC. The images below demonstrate the performance we were able to get.

Outernet Signal

Outernet Signal

Outernet Signal with 4x Decimation

Outernet Signal with 4x Decimation

AERO

AERO

STD-C EGC

STD-C EGC

The Outernet team writes that a SNR level of only 2 dB is needed for decoding to work on their signal. With the patch and LNA we were able to get at least 12 dB so this is more than good enough. Other signals such as AERO and STD-C EGC also came in very strongly. Even when not angled at the satellite and placed flat on a table it was able to receive the signal with about 5 dB’s of SNR.

In conclusion the patch and LNA worked very well at receiving the Outernet signal as well as AERO and STD-C EGC. We think these products are great value for money if you are interested in these L-Band signals, and they make it very easy to receive. The only minor problem with the patch antenna is that there is no stand for it, which makes it difficult to mount in a way that faces the satellite. However this issue can easily be fixed with some sellotape and your own mount.

In the future once the Outernet Rpi3 OS and decoder image is released we hope to show a demonstration and tutorial on receiving Outernet data.

RTLSDR4Everyone Four New Posts: Janilab Preamp Review, Why Use a Preamp?, Small ADS-B Antennas Review, SDRUno User Guide

Akos from the RTLSDR4Everyone blog has recently posted three new articles. The first article reviews the Janilab LNA Preamp which has a frequency range of 1 MHz to 3 GHz and an adjustable gain. In the review he compares reception with and without the preamp at shortwave frequencies and at ADS-B frequencies. Finally he also compares it against the LNA4ALL and LNA4HF, and notes that they generally have better specs than the Janilab preamp, but the disadvantage is needing two to cover HF + VHF/UHF, meaning an increase in costs.

In his second post Akos explains when and why you should use a preamp. Basically he explains how the lower noise figure of the preamp can help improve SNR.

In his third post Akos does a review on small ADS-B antennas. These are small whip type antennas that are tuned for 1090 MHz. In his testing he found that a telescopic antenna gave significantly better results that the ADS-B whip, but recognizes that these are designed for pilots and light aircraft owners who need a small sturdy antenna.

Finally his fourth post he shows an updated beginners guide for SDRuno. SDRuno is the official software for the SDRplay RSP, but is compatible with the RTL-SDR.

The LNA4ALL and LNA4HF vs the Janilab Preamp
The LNA4ALL and LNA4HF vs the Janilab Preamp

Testing L-Band Inmarsat Reception with Three LNA4ALL’s + Two Filters

Over the last few weeks Adam 9A4QV has been testing L-Band Inmarsat reception with his LNA4ALL low noise amplifiers. In a previous post he tested reception with two LNA4ALL and found that he got an improved SNR ratio over using just one LNA4ALL. In his latest video he tests Inmarsat reception with three LNA4ALL’s and two L-band filters. His results show that the SNR is improved over using two LNA4ALL’s, and can almost match the results obtained by a commercial L-band front end which he also demonstrated in a previous video.