A new super budget HF upconverter has appeared over on cosycave.co.uk, a UK based trading site. It is currently priced at £9.99. The budget HF upconverter uses a 50 MHz oscillator and an NE602AN double balanced mixer and oscillator integrated circuit. It is only suitable for use on the R820T and is incompatible with the E4000.
This circuit appears to have no preselection or filtering circuits.
Over on YouTube user Theo Faber has uploaded a video showing his adjustable multiband HF preselector project for his RTL-SDR dongle. The preselector covers the entire HF band. Theo designed and built his own homemade upconverter for this project as well.
Preselectors on the RTL-SDR can vastly improve reception quality. Without preselection, noise and strong images of other nearby stations can cause strong interference.
My project ‘pre selector’ for wideband radios and in particular the popular tv-sticks than can be used for SDR reception. The sticks are very cheap and the software free available on the internet. SDR Sharp in this case, is operating stable under XP and W7. Sticks are sensitive, however the input level can only vary +- 20dB. The sticks are easely overloaded and will produce cross and intermediation. So you need in front of the stick / converter band pass or tunable filters. Hopefully this inspired you to build your own set of filters, to fully benefit from the perfect performing of this affordable SDR.
for more info contact me on: t.faber87__AT__upcmail.nl
kind regards and 73’s
Hak5, a popular YouTube technology show has recently been dedicating a bunch of episodes to RTL-SDR projects. Recently we posted about their efforts with ADS-B, and some GNU Radio tutorials. Their most recent video discusses AIS (Automatic Identification System) which is a system similar to ADS-B which ships use to transmit their location to create a modern GPS based radar system.
The Hak5 video discusses how AIS works and also shows how to use an RTL-SDR to receive it. In their tutorial they use SDR#, VBCable and ShipPlotter to receive and view AIS data on map. Note that we also have an AIS tutorial here.
The HackRF One, a TX/RX capable software defined radio for 10 MHz – 6 GHz is now available for preorder at certain resellers for $299USD . Micheal, the man behind the HackRF expects the Kickstarter HackRF rewards to be shipped in June. Then after shipping the HackRF reward units, the resellers will receive their units.
HackRF One from Great Scott Gadgets is a Software Defined Radio peripheral capable of transmission or reception of radio signals from 10 MHz to 6 GHz. Designed to enable test and development of modern and next generation radio technologies, HackRF One is an open source hardware platform that can be used as a USB peripheral or programmed for stand-alone operation.
- 10 MHz to 6 GHz operating frequency
- half-duplex transceiver
- up to 20 million samples per second
- 8-bit quadrature samples (8-bit I and 8-bit Q)
- compatible with GNU Radio, SDR#, and more
- software-configurable RX and TX gain and baseband filter
- software-controlled antenna port power (50 mA at 3.3 V)
- SMA female antenna connector
- SMA female clock input and output for synchronization
- convenient buttons for programming
- internal pin headers for expansion
- Hi-Speed USB 2.0
- USB-powered
- open source hardware
HackRF One has an injection molded plastic enclosure and ships with a micro USB cable. An antenna is not included. ANT500 is recommended as a starter antenna for HackRF One.
AIS enthusiast K2NCC has posted in our forum a link to a PDF document he has created showing how to use SDR#, AISMon and AIS Dispatcher to report AIS data to marinetraffic.com and aishub.net. Marinetraffic.com and Aishub.net are websites which aggregate AIS data from various contributors around the world.
AIS is an acronym for Automatic Identification System and is a type of modern GPS based radar system similar to ADS-B used by mariners to help avoid collisions at sea.
Recently a bunch of amateur radio nano-satellites known as ‘Kicksats‘ were launched on the latest SpaceX rocket. So far the Kicksat carrier has been successfully deployed, which is essentially the box containing the nano-satellites. On May 4, the nano-satellites known as ‘sprites’ are due to be deployed from the carrier.
Both the carrier and Kicksat sprites have telemetry signals which are receivable with the RTL-SDR. As the sprites transmit using only 10mW of power, a high gain Yagi antenna and an LNA are required to receive their signals.
Over on his blog, Dolske has been trying to receive and record the Kicksat carrier using his RTL-SDR. He was able to capture a telemetry packet at 437.505 MHz using SDR#. He then tried to use QTMM AFSK1200 to decode the packet, but has been unsuccessful so far probably due to the weak signal he received.
Over on YouTube user mutezone has posted a video comparing the RTL-SDR with upconverter against a Softrock Ensemble II software defined radio. The Softrock Ensemble II is an SDR dedicated to the HF frequencies and is thus expected to have better performance for that purpose. Mutezone writes
A performance between the Softrock Ensemble II vs the RTL-SDR (R820T) on shortwave. Here we are trying to see which one is best at receiving AM broadcasters. Both SDRs were using the same longwire antenna connected to an ATU (Antenna Tuning Unit).
Although I know this comparison is somewhat unfair, since the RTL-SDR is not meant for shortwave & the Softrock is, it is to show that there is a difference in performance, even though the RTL-SDR has a much wider frequency range & cannot be beaten when it comes to value for money. My opinion is that if you want an SDR that should deliver on HF / Shortwave performance, then go for a dedicated one like the Softrock, Afedri, SDR-IQ or any others that do the same job on the market. Even when using a decent HF Upconverter, the RTL-SDR will still not match the performance of more upmarket HF SDRs.
Over on YouTube, Hak5 a electronics enthusiast channel has posted a video showing an interesting ADS-B project they undertook.
The Hak5 team took a quadcopter up on top of a high mountain, attached to it a WiFi Pineapple (a small WiFi equipped Linux computer), an RTL-SDR dongle and a coax collinear antenna and then flew it up high. They ran dump1090, a Linux based ADS-B decoder on the WiFi pineapple and then broadcast the decoded information back to a laptop on the ground.
Although the results were less than favourable, it is still an interesting project to explore. Their poor results may be due to a nearby RF broadcast tower which could have been overloading the dongle, or EMF from the quadcopter motors.
