December 27, 2017

Outernet 3.0 Coming Soon: Free 30kbps – 100kbps satellite data downlink for news, weather, audio etc

Over the past few years we've posted quite a bit about Outernet who offered a free downlink of satellite data such as news, Wikipedia articles and weather updates that was able to be received with a small L-band patch antenna, LNA and an RTL-SDR dongle.

Recently we've seen news on their forums that Outernet is planning on discontinuing their L-band service, and instead opening up a new much more efficient Ku-band service. Unfortunately that means that RTL-SDRs and the previous Outernet L-band hardware will no longer be useful for the downlink, but the new service appears to offer several significant advantages.

Firstly the downlink data rate is much higher at 30kbps, with the plan to eventually go up to 100kpbs. That's 300MB - 1 GB a day which is a lot more compared to the previous L-band implementation that gave less than 20MB a day.

Secondly the hardware seems to be simplified as well. All that is needed is their new Dreamcatcher V3 receiver board and a small Ku-band LNB (11.7-12.75 GHz). They claim that no dish is required as the LNB pointed at the satellite by itself will work just fine. The first iteration of Outernet also used Ku-band satellites, but required a large dish antenna to receive it which was a major hurdle to user adoption. They now appear to have discovered a new way to broadcast in the Ku-band without the need for a dish.

Thirdly, moving to Ku-band means significant cost savings for Outernet allowing them to survive and continue with their free data service. From what we understand the L-Band satellite downlink service is extremely costly to run, whereas a Ku-band service is much cheaper. There are also cost savings for the user as Ku-band LNBs are very common hardware that can be found cheaply for $10 - $20 US.

About the new services that they can offer and the cost savings that they can achieve Syed the CEO of Outernet writes:

The fatter pipe [300MB - 1GB] makes a lot of things possible, one of which is a true radio broadcast. How about a national radio broadcast that isn't SiriusXM? Our new receiver will include a speaker; audio through the speaker while files download in the background. But more data is not the most important thing that comes out of all this. The real win is that leasing standard, commodity Ku bandwidth is far, far more cost effective than the few kilohertz we have on L-band. Long-term sustainability of a free broadcast is no longer the financial burden that it once was--especially considering how much more interesting the service becomes.

There is no concrete hardware release date just yet, but on the forums Syed estimates mid-Jan. You can sign up to the Outernet mailing list on their buy-now page to be emailed when the new hardware is released. In the forums Syed also writes that the target price for the hardware is $99 US, with the intention to provide lower cost options in the future. Of course it might still be possible to DIY your own unit just like it was with the previous Outernet iterations.

We're really looking forward to this and think that this is what will finally make Outernet a very popular and useful service!

Tweet57

Reddit183

Vote

240 Shares

December 24, 2017

Video Comparison of the Airspy HF+ and SDRplay RSP1A on the FM Broadcast Band

Frequent reviewer of SDR products Mile Kokotov has just uploaded on his YouTube channel a new video where he compares the Airspy HF+ against the SDRplay RSP1A on FM broadcast reception.

At first Mile compares the two against strong broadcast stations, and then later compares them on weak DX stations surrounded in amongst other strong stations. With the strong stations a difference between the two radios is impossible to detect. But with the weaker stations that are surrounded by strong signals the Airspy HF+ has the edge with it's higher dynamic range and sensitivity.

Mile writes:

In this video I am comparing two popular SDR-Receivers (Airspy HF+ and SDRplay RSP1A) on FM Broadcast Band.

I have made few recordings with every receiver with the same antenna trying to set the best SNR = signal-to-noise ratio.

My intention was to ensure the same conditions for both SDR`s in order to make as fair as possible comparison.

No DSP enhancing on the SDR`s was used.

Antenna was Vertical Dipole.

When receiving signals are strong enough, You should not expect the difference between most receivers to be very obvious!

If you compare one average transceiver (which cost about $ 1000 USD) and top class transceiver which cost ten times more, the difference in receiving average signals will be very small too. Almost negligible! But when you have difficult conditions, the very weak signal between many strong signals, than the better receiver will receive the weak signal readable enough, but cheaper receiver will not. Today it is not a problem to design and produce the sensitive receiver, but it is far more difficult to design and produce high dynamic receiver for reasonable price! The Airspy HF+ and RSP1A are very very good SDR-receivers. They have different customers target and have strong and weak sides. For examle Airspy HF+ has better dynamics in frequency range where it is designed for, but RSP1A, on the other hand, has broadband coverage...

Airspy HF+ vs SDRplay RSP1A Comparison on FM Broadcast Band

Watch this video on YouTube

Vote

December 22, 2017

An RTL-SDR Based Ground Penetrating Radar & Metal Detector

Thanks to Dr. Celalettin Uçar from Turkey for submitting a video of the work done by a PhD student who as part of his research created an RTL-SDR based ground penetrating radar simulation and metal detector. He writes:

This apparatus (YAĞRIN) was created with rtlsdr in a phd work. We achieved detecting a metal gasoline tube from the depth of aproximately 1 meters. Furthermore, we created the time domain signal and ploted the reflaction from the metal with using the matlab (simulink) model.

A video on YouTube is linked which we display at the end of the post. They write that the system consists of a 12V DC supply, step down voltage regulator, ADF 4350 programmable signal generator, 25W power amplifier (470 MHz, 45 dBm signal power), Philips omnidirectional antennas (RX,TX), a 64 dB low noise amplifer and an RTL-SDR and computer to display the output. The software he uses is SDR# which appears to simply listen for a tone and detect any changes that occur when something metal moves near it. The PC also runs a MATLAB Simulink model which we believe helps detect metal signatures by plotting the reflection.

In the past we posted about a similar but simpler metal detector implementation by Ancient Discoveries.

RTL-SDR BASED GPR (Simulation) & METAL DETECTOR (YAĞRIN) - Dr. Celalettin UÇAR

Watch this video on YouTube

Vote

December 21, 2017

A YouTube Review of the ColibriNANO SDR with Remote Server and Web Interface Demo

Over on YouTube user Laboenligne.ca has uploaded a review of the ColibriNANO. If you didn't already know the ColibriNANO is a low cost but high performance direct sampling receiver designed for the HF bands. Currently it costs $269.95 US from nsiradio. It now competes almost directly with the recently released Airspy HF+ which is a lower cost $199 unit with similar performance specifications.

Laboenligne.ca's review initially goes over the specs of the ColibriNANO and usage of the free ExpertSDR2 software that is used with the ColibriNANO. He also shows how the ColibriNANO can be connected to a Raspberry Pi 3 and used remotely over the internet. This is similar to the Airspy's SpyServer, but the difference is that ColibriNANO's server interface works in a browser via HTML5, so it can be used on any platform including mobile devices. Of course the ExpertSDR2 software can also be used to connect to the server as well. In his review Laboenligne.ca notes that he is very impressed with the remote web interface and has set up a public server demonstration of his ColibriNANO available at vpn.laboenligne.ca. He notes that if there is no reception to try again later, as he may be using the antenna on another radio.

The ColibriNANO SDR receiver review (English version)

Watch this video on YouTube

Vote

December 21, 2017

Monitoring Home Power Consumption with an RTL-SDR

Over on his blog "K-roy" has completed a writeup discussing how he is using an RTL-SDR dongle to monitor and graph the power usage of his home. After seeing multiple ads for the Sense home power usage monitor, K-roy decided to roll his own similar device instead.

Many homes in the US and elsewhere no longer require meter reader personnel to come onto the property to read a physical meter at the back of the house. Instead the meter transmits wireless data in the 900 MHz ISM band about electricity usage, and all the meter reader has to do is turn up outside the house and take a reading from the street.

These electricity usage signals are unencrypted and can easily be decoded and displayed with an RTL-SDR and a ready to use program called rtl_amr. The signals even travel quite far, and there have been reports of receiving neighbours signals up to 600m away. K-roy took his RTL-SDR and rtl_amr and wrote on top of it a program that creates a JSON output of the data for easy processing, a PHP, SQLite3 and JQuery based database system for storing the data, and an HTML5 based page for graphing and displaying the data.

If you are interested, there is also a discussion about K-roy's work over on Reddit.

Power usage data collected and graphed by K-roys RTL-SDR, rtl_amr and his software.

Vote

December 21, 2017

A Tiny Object/Animal Tracking Device with RTL-SDR + Yagi Locator

Over on Hackaday.io we've come across a project by "Tom" who has created a small tracking device which is located using an RTL-SDR dongle and directional Yagi antenna. The tracking device itself is a simple fingernail sized low power UHF transmitter that transmits short pulses about every second or so in the 915 MHz ISM band. Tom writes that the range is about 400m (line of sight) and with a small button cell battery the device lasts a couple of days with its 180 uA current draw. Presumably longer operation could be achieved by significantly reducing the pulse rate of the circuit.

To receive the tracking device an RTL-SDR is combined with a high gain directional Yagi antenna, a three level 10 - 30 dB attenuator and an Android phone running the RF Analyzer app. The idea is to simply use the attenuator and directional Yagi antenna to determine the direction in which the signal is strongest. That direction with the strongest signal will indicate where the transmitter is. Tom's video below shows an example of the transmitter and RTL-SDR based tracking setup.

Low-tech Tiny UHF tracker transmitter

Watch this video on YouTube

Vote

December 20, 2017

SDR# Noise Reduction Plugins Updated + SDR-Console Testing Deep Learning Noise Reduction

Recently the SDR# team have updated the algorithm on the noise reduction plugins used in SDR#. It appears that both the IF and Audio noise reduction plugins were updated with a better smoothing algorithm. We briefly tested the new algorithm and compared it against an older version. The new algorithm has noticeably less hiss and is slightly clearer when compared at the same noise reduction level. We tested with the same threshold levels and using the speech profile.

At the same time we've also seen news that Simon of SDR-Console is working on another noise reduction algorithm based on deep neural networks in the latest private beta version. A video of it in action was posted by Paul J in the SDRplay users group (note that you will need a Facebook account and will probably need to be a member of the SDRplay group to view that video). The algorithm seems to be based on the RNNoise paper that was posted here. The SDR# algorithm was also tweaked based on information gained from that paper although it doesn't use neural networks directly.

SDR# NR Comparison

Unprocessed Audio

Old SDR# NR Algorithm

New SDR# NR Algorithm

Vote

December 19, 2017

Displaying Live Weather and Traffic Data from HD Radio (NRSC-5) Signals

Thanks to KYDronePilot for submitting news of his new Python based script called HDFM which displays live weather and traffic data from data that is embedded into iHeartRadio HD Radio (NRSC-5) radio stations.

If you are in the USA, you might recognize HD Radio (aka NRSC-5) signals as the rectangular looking bars on the frequency spectrum that surround common broadcast FM radio signals. These signals only exist in the USA and they carry digital audio data which can be received by special HD Radio receivers. Earlier in the year in June a breakthrough in HD Radio decoding for SDRs like the RTL-SDR was achieved by Theori when he was able to piece together a full HD Radio software audio decoder that works in real time.

It turns out that some of these HD Radio signals run by iHeartRadio also contain other data streams such as live weather and traffic data that is consumed by HD Radio based car GPS receivers or audio head units in US vehicles. HDRadio.com also write that they can embed other data such as sports scores and emergency messages into the data stream as well.

KYDronePilot's Python script utilizes Theori's decoder to save all received weather and traffic data maps for a folder. Below is an example of traffic and weather data that he received.

Tweet13

Reddit57

Vote

70 Shares