Tagged: LNA

New Products in Our Store: Wideband LNA + Spare V3 Metal Enclosures

We've just released two new products in our store. The first is a low cost general purpose wideband LNA and the second is some spare RTL-SDR V3 aluminum enclosures. The wideband LNA is currently available for shipping from our Chinese warehouse and will be available on Amazon in a few days time. It costs US$17.95 including worldwide free shipping. The spare aluminum enclosure is only available from our Chinese warehouse and costs US$5.95.

Please Click Here to Visit our Store

Wideband LNA

The Wideband LNA is based on the Qorvo SPF4189Z LNA chip (datasheet pdf) which has the following declared specs:

  • Frequency range of 50 MHz to 4000 MHz
  • Noise figure = 0.6dB @ 900 MHz
  • OIP3 = 39.5 dBm @ 900 MHz
  • P1 Saturation = 22.7 dBm @ 1960 MHz
  • Gain = 18.7 dB @ 900 MHz

Compared to most of the other SPF5189Z LNAs found on eBay, our wideband LNA comes standard with a full conductive metal case, includes ESD protection on the antenna input, and is by default powered via 3 - 5V bias tee power. Our RTL-SDR Blog V3 dongles have a 4.5V bias tee built in, so they can be used to power this LNA. Direct power can be enabled simply by changing a jumper position, and removing the metal case.

This is a general purpose wideband LNA. It is useful for reducing the noise figure and thus increasing SNR, and for overcoming coax loss on all supported frequencies between 50 - 4000 MHz. However, because it is wideband you may need additional filtering if you have strong overloading signals in your area. If you're mostly interested in improving ADS-B reception, then we instead recommend our Triple Filtered ADS-B LNA which is also available at our store. The specs of the SPF5189Z are similar to that of PGA-103+ or PSA4-5043+ based LNAs. In the image slider below we compare the gain with the LNA4ALL which is a PSA4-5043+ based LNA.

Spare Aluminum Enclosure

The second product is some spare RTL-SDR Blog V3 aluminum enclosure. A few readers of this blog contacted us as they found RTL-SDR V3 enclosures to be a good fit (after being cut down to size) for home made filters, other LNAs and for FlightAware dongles. Our spare enclosures come with two SMA side panels, and one USB side panel. There is only limited stock of this product at the moment. Note that we're not including a thermal pad, since FlightAware dongles do not require additional cooling since they operate at 1.09 GHz. Additional cooling via thermal pad is only needed for stable operation when using RTL-SDRs above ~1.5 GHz.

WidebandLNA_Store
WidebandLNA_PCB_Store
wideband_lna_gain
spare_enclosure_shop

New Products in Our Store: Wideband LNA + Spare V3 Metal Enclosures

We've just released two new products in our store. The first is a low cost general purpose wideband LNA and the second is some spare RTL-SDR V3 aluminum enclosures. The wideband LNA is currently available for shipping from our Chinese warehouse and will be available on Amazon in a few days time. It costs US$17.95 including worldwide free shipping. The spare aluminum enclosure is only available from our Chinese warehouse and costs US$5.95.

Please Click Here to Visit our Store

Wideband LNA

The Wideband LNA is based on the Qorvo SPF4189Z LNA chip (datasheet pdf) which has the following declared specs:

  • Frequency range of 50 MHz to 4000 MHz
  • Noise figure = 0.6dB @ 900 MHz
  • OIP3 = 39.5 dBm @ 900 MHz
  • P1 Saturation = 22.7 dBm @ 1960 MHz
  • Gain = 18.7 dB @ 900 MHz

Compared to most of the other SPF5189Z LNAs found on eBay, our wideband LNA comes standard with a full conductive metal case, includes ESD protection on the antenna input, and is by default powered via 3 - 5V bias tee power. Our RTL-SDR Blog V3 dongles have a 4.5V bias tee built in, so they can be used to power this LNA. Direct power can be enabled simply by changing a jumper position, and removing the metal case.

This is a general purpose wideband LNA. It is useful for reducing the noise figure and thus increasing SNR, and for overcoming coax loss on all supported frequencies between 50 - 4000 MHz. However, because it is wideband you may need additional filtering if you have strong overloading signals in your area. If you're mostly interested in improving ADS-B reception, then we instead recommend our Triple Filtered ADS-B LNA which is also available at our store. The specs of the SPF5189Z are similar to that of PGA-103+ or PSA4-5043+ based LNAs. In the image slider below we compare the gain with the LNA4ALL which is a PSA4-5043+ based LNA.

Spare Aluminum Enclosure

The second product is some spare RTL-SDR Blog V3 aluminum enclosure. A few readers of this blog contacted us as they found RTL-SDR V3 enclosures to be a good fit (after being cut down to size) for home made filters, other LNAs and for FlightAware dongles. Our spare enclosures come with two SMA side panels, and one USB side panel. There is only limited stock of this product at the moment. Note that we're not including a thermal pad, since FlightAware dongles do not require additional cooling since they operate at 1.09 GHz. Additional cooling via thermal pad is only needed for stable operation when using RTL-SDRs above ~1.5 GHz.

WidebandLNA_Store
WidebandLNA_PCB_Store
wideband_lna_gain
spare_enclosure_shop

Japanese RTL-SDR Products Now Available for International Shipping on Amazon.co.jp

Thanks to 'Nobu' for letting us know that his RTL-SDR products sold on Amazon.co.jp are now available for international shipping (in Japanese, please use the Google Translated version if needed). Before Amazon.co.jp offered international shipping you had to use a third party Japanese forwarding service in order to purchase his products.

Japan has a strong RTL-SDR scene, with a few small Japanese companies and individuals (including Nobu) selling custom RTL-SDR products on their local Amazon store. Products such as upconverters, galvanic isolators, LNAs, filters, cooling products and more are available. Back in 2015 we reviewed some of these products in a post available here. Since then we've found continued use in particular with the galvanic isolator which helps reduce noise from the computer and nearby electronics at HF frequencies. 

Some Japanese RTL-SDR Products available for International Shipping on Amazon.co.jp
Some Custom Japanese RTL-SDR/RF Products available for International Shipping on Amazon.co.jp

NooElec SAWBird: An LNA + Filter for GOES Weather Satellite Reception Now Available

NooElec has just released their new "SAWbird" GOES LNA for sale. This is an LNA and filter combination designed to help receive GOES weather satellite images. On the PCB is a 1688 MHz SAW filter and a low noise amplifier. It can be powered with 3V - 5.5V connected directly or via bias tee. The SAWbird is currently available on Amazon and their store for US$34.95. They also have a version for Inmarsat and Iridium, so make sure you choose the correct one.

GOES 15/16/17 are geosynchronous weather satellites that beam high resolution weather  images and data. In particular they send beautiful 'full disk' images which show one side of the entire earth. As GOES satellites are in a geosynchronous orbit, the satellite is in the same position in the sky all the time, so no tracking hardware is required and images can be constantly pulled down throughout the day without having to wait for a satellite to pass over. 

However, compared to the more familiar and easier to receive low earth orbit satellites such as NOAA APT and Meteor M2 LRPT, geosynchronous satellites like GOES are quite a bit further away, and transmit at 1.7 GHz. So to receive the signal you'll need a dish antenna that you can accurately point, a good low noise figure LNA and possibly a filter. So setting up a receiver is a bit more difficult when compared to receivers for NOAA and Meteor satellites. The SAWbird should help however, by providing a ready to use LNA+Filter combination.

Over the past few months several testers have already received engineering samples of the SAWbird and have been successful at receiving GOES images. From the results of several experimenters, it appears to be possible to use a cheap 2.4 GHz WiFi grid antenna with some minor modifications as a GOES satellite antenna. Get one with at least a one meter long width and bend the feed as described here or here to tune reception for the 1.7 GHz GOES frequency. Pieter Noordhuis has also shown that it's possible to use an RTL-SDR to receive GOES images, so an entire GOES system can be built on a budget.

NooElec SAWbird LNA + Filter for GOES reception.
NooElec SAWbird LNA + Filter for GOES reception.
GOES Full Disk Image of the Earth
GOES Full Disk Image of the Earth

Getting the V3 Bias Tee to Activate on PiAware ADS-B Images

A few owners of our RTL-SDR V3 and/or our Triple Filtered ADS-B LNA (or other bias tee powered LNAs) have been having trouble getting the V3 bias tee to activate on the FlightAware PiAware Raspberry Pi image. The core stumbling point is that the PiAware image activates the dump1090 ADS-B decoder immediately upon boot. To activate the bias tee, the bias tee software requires access to the dongle which it cannot get since dump1090 is blocking it. So to get around this the bias tee must be activated first before dump1090 runs.

PiAware is FlightAware's Raspberry Pi image which feeds their flightaware.com flight tracking service using RTL-SDR dongles. By using our Triple Filtered ADS-B LNA, users can expect increased range and decoded messages, especially when using long runs of coax cable, and/or in environments with strong interfering signals.

In the instructions below we'll explain how to set up a PiAware image that automatically enables the Bias Tee upon boot.

Downloading the V3 Bias Tee Software onto PiAware

First we assume that you're starting fresh from a new PiAware image, so we need to enable WiFi and SSH connections which is part of the standard set up for PiAware. See the following links for instructions.

Enable WiFi via config file https://flightaware.com/adsb/piaware/build

Enable SSH by adding ssh file to boot https://flightaware.com/adsb/piaware/build/optional#password

 
Now log in to your PiAware machine using SSH and PuTTY (or any other terminal software) using username "pi" and password "flightaware".

Run the following commands to update and install some dependencies. 

sudo apt-get update
sudo apt-get install git cmake build-essential libusb-1.0-0-dev

 
Download and install the RTL-SDR V3 Bias Tee software.

cd ~
git clone https://github.com/rtlsdrblog/rtl_biast
cd rtl_biast
mkdir build
cd build
cmake ..
make

Testing the Bias Tee

Over on his blog Akos has created a short guide to activating the bias tee manually, by first stopping dump1090, activating the bias tee, then restarting dump1090. It's a simple one line copy and paste job.

So after installing the rtl_biast software above you can use the following line to test the bias tee. After running this line the FlightAware service should be up and running again, with the bias tee and LNA activated.

sudo service dump1090-fa stop && cd ~/rtl_biast/build/src && ./rtl_biast -b 1 && sudo service dump1090-fa start

Automatically Starting the Bias Tee on Boot

Ideally we don't want to have to reactivate the bias tee manually every time the Raspberry Pi reboots. To make it automatic use the following instructions:

First create a service directory and configuration file

sudo mkdir /etc/systemd/system/dump1090-fa.service.d
sudo nano /etc/systemd/system/dump1090-fa.service.d/bias-t.conf

 
Then paste in the following

[Service]
ExecStartPre=/home/pi/rtl_biast/build/src/rtl_biast -b 1

 
Finally press Ctrl+X then Y to close and save. Now whenever PiAware reboots the bias tee should be automatically activated as this service runs before dump1090 is activated.

Credits:

Thanks to the discussion on the FlightAware forums and in particular user 'obj' for originally finding this automatic solution.

Tysonpower Reviews our Triple Filter ADS-B LNA

Thank you to YouTuber 'Tysonpower' who is known for making various RF related videos as he has recently reviewed our Triple Filtered ADS-B LNA on his blog and on YouTube. Note that his video is in German, but it contains English subtitles. In the review he compares our LNA against a more expensive ADS-B LNA and found that it performs just as good, if not better in some cases. 

Our ADS-B LNA uses a triple filter design, as well as a two stage LNA which aims to significantly cut out interference from out of band signals which could overload the LNA and/or SDR dongle. It also has a low noise figure and high output gain of 27dB which is great for reducing losses on long runs of coax cable. More information about our LNA on the release post, and it can be purchased from our store.

[EN subs] Top ADSB LNA für nur 25€ - RTL-SDR Blog LNA

Radio For Everyone: Testing the RTL-SDR.com Triple Filtered ADS-B LNA, Amplified Coketenna

Akos, author of his blog 'Radio for Everyone' has recently reviewed our new RTL-SDR.com Triple Filtered ADS-B LNA. In the review he compares our ADS-B LNA against another external ADS-B LNA by Uputronics and against the FlightAware Prostick and Prostick+. The tests use the external LNA's plugged directly into the dongle in order to more fairly compare against the FlightAware dongles which have LNA's built in to the dongles themselves. From his results the RTL-SDR.com ADS-B LNA appears to have near identical results with the Uputronics LNA, and slightly better results compared to the FlightAware dongles. Akos has not yet tested the main use-case of the LNA, which is to use it at the end of a run of coax cable, however he plans to do this in a future test. Also in his second post Akos shows how to build a simple amplified Coketenna using our ADS-B LNA.

On the subject of ADS-B performance we note that there are two ways to set up a system for optimal reception (apart from the antenna). The first is to place the computing and radio devices (such as a Raspberry Pi and RTL-SDR) as close to the antenna as possible (leaving a ~1m coax run to avoid local interference from the Pi). For this type of setup it is cheaper to use a FlightAware Prostick Plus RTL-SDR dongle since this has an ADS-B LNA built into it. However, the disadvantage is that you may need to set up a Power over Ethernet system, or find a remote power source, and possibly place the Pi in a difficult to service location such as in an attic or up a mast.

The second option is to use an external ADS-B LNA close to the antenna, and run coax down to the computing device which is positioned in a more accessible location. The LNA will negate any losses in the coax cable, and with high enough gain on the LNA, using quality coax is not such a high requirement since those losses are negated by sufficient LNA gain. Both methods will yield similar excellent performance.

Tested ADS-B LNA's and ADS-B RTL-SDR Dongles
Tested ADS-B LNA's and ADS-B RTL-SDR Dongles

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.

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.

In addition please remember that this is a high gain LNA. It is expected to be used at the antenna side, with some 3+ db loss expected on the coax. However, if desired, it can still be used on the receiver side. If used on the receiver side or with a low loss run of coax, you will need to tune the RF gain on the RTL-SDR dongle. By default most software sets the RF gain to maximum. We recommend turning the RTL-SDR RF gain down to about 32 dB if connecting it directly to the dongle, otherwise the high input power may overload the dongle causing poor performance.

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

VNA_180530_231521

Reviews

Tyson Power YouTube Review

Radio For Everyone Review

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.

LNA4ALL on the VHF close to antenna effect