Over on YouTube user Adam Alicajic has recently been uploading videos that show him testing a prototype of his upcoming product the MIX4ALL. The MIX4ALL is an RF downconverter which will allow the RTL-SDR to receive signals at around 1.5 GHz or higher. Although the RTL-SDR can already tune up to ~1.7 GHz, above about 1.2 GHz sensitivity is poor and some units have problems receiving when they get hot. The downconverter will convert a 1.5 GHz signal into a signal at around 250 MHz, where the RTL-SDR operates well. At around 1.5 GHz there are several satellite signals of interest including Inmarsat EGC, Iridium and AERO signals.
On one video Adam decided to use the MIX4ALL to test the difference between a GPS patch antenna and a home made air gap patch antenna. The GPS patch antenna was salvaged from an old GPS receiver and the patch antenna is the one discussed in this previous post. In the test Adam used the MIX4ALL and an RTL-SDR, and tested reception of Inmarsat signals. His results showed that the reception given by the GPS patch was very poor compared to the home made patch antenna.
Comparing the GPS and DIY Patch antenna for the L-band INMARSAT
GPS antenna match on L-band 1575 MHz
Some other recent videos by Adam show him also testing his MIX4ALL with S-Band signals around 2.3 GHz and also receiving Alphasat XL.
MIX4ALL receiving on S-band terestrial weak signals
Alphasat XL band spectrum using the converter and R820T dongle
Adam (9a4QV) is well known in the RTL-SDR community for creating and selling the LNA4ALL low noise amplifier and several filter circuits as well. Now Adam has uploaded on his YouTube channel a new video that shows a prototype of his latest upcoming RTL-SDR compatible product called the MIX4ALL. The MIX4ALL is a downconverter that will improve the ability of the RTL-SDR to receive satellite signals in the L-band which are usually at around 1.5 GHz.
It is known that the most common R820T/2 RTL-SDR’s are not very sensitive at 1.5 GHz, and some can even stop receiving properly at this frequency when they get too hot. A downconverter will simply convert the 1.5 GHz signals into a lower frequency which can be received much better by the RTL-SDR.
In the first video Adam shows the MIX4ALL being used with an RTL-SDR to receive various Inmarsat signals with a patch antenna. In the second video he shows reception of AERO-I signals.
Adam writes that he expects to be able to sell the MIX4ALL near the end of January 2016.
MIX4ALL test @ L-band Inmarsat
MIX4ALL AERO-I L band Inmarsat 4F2