The RX888-MKII radio

 

RX888 mkII is the new generation of RX888 with the following improvements and enhancements:
1.Add a tunable Attenuator in the HF path, which can tune from 0 to -31.5dB.
2.Change the fixed LNA of RX888 to a VGA, which gives the -10dB to +33dB range. VGA applies to both HF and VHF.
3.Use the newer generation of tuner chip R828D instead of R820T2.
4.Use an enhanced version of 64M LPF to improve image rejection further.
5.A jumper can select the internal reference clock or an external 27Mhz reference clock.
The primary motivation is giving users smaller granularity control on the RF front-end and a big dynamic range to fit the demands of both strong and weak signals receiving. The tunable range is -41.5dB to +33dB for HF and 0db to 55dB for VHF, which covers most use cases. During the mkII development, we are working very closely with the original author of BBRF103, IK1XPV, on his new universal driver. The new driver supports RX888 and RX888 mkII now. The new driver can download here: https://github.com/ik1xpv/ExtIO_sddc…. And we expect the power of opensource will significantly improve the software support and the lifetime of RX888.

Technical specifications:
1.LTC2208 16bit ADC @ 130 MSPS
2.Dual RF input, HF frequency range:1kHz-64Mhz, maximum real-time bandwidth 64M. VHF
frequency range:64M-1700Mhz, maximum real-time bandwidth 10M.
3.0.5ppm VCXO
4.ATT adjustment range -32dB to 0dB
5.VGA adjustment range -11dB to +34dB
6.External 27Mhz reference clock support
7.3.3v software switched Bias-Tee HF/VHF independent control
8.ADC PGA Rand Dither software control
9.Support mainstream SDR software such as HDSDR SDRConsole SDR# SDR++

Package Included:
- 1 * SDR Radio

- 1* USB3.0 cable

 

What we specifically like and use in our new websdr design is:

- direct conversion from radio signal to 16 bits data. No IQ techniques used anymore.

- it scans the complete HF band at once

- externally controllable  with precision clock signal

- easy testable with SDRConsole

 

What we dislike is the heat control, so we took some measurements to better cool the unit.

 

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