Sunday, July 05, 2015

RFSpace CloudIQ: Sensitivity & I/Q Bandwidth

Sensitivity may not be an important issue for many DX-ers, especially if they live in a high signal level environment. To me, sensitivity is an important issue, and I always make sure to measure the sensitivity levels of my receivers.

Up until now, all SDRs have been somewhat inferior to the best conventional receivers. Such as the NRD-525 (-114 dBm) and the R-390A (-116 dBm).

My SDRs of various guises have weighed in at -93 to - 106 dBm, with the exception of the Winradio G33DDC which made the -110 dBm mark with the preamp engaged.

RFSpace promised the CloudIQ to be considerably more sensitive that the SDR-IQ, and indeed we have a new SDR winner of the weak signals prize. The sensitivity was a uniform -111 dBm from 500 kHz (my lowest measurement) to 20 MHz (my highest). The measurements were done in AM mode, 6 kHz bandwidth, 400 Hz tone into 30 % modulation.

Pieter Ibelings at RFSpace informed me that they had spent a lot of time on the matching of the ADC. Evidently their efforts paid off.
The 19 meter band on the CloudIQ
The I/Q sample rate maxes out at 1 MHz, 24 bits. Now, this is a little less than desired for recording the MW band for later analysis, as 160 kHz on the 540-1700 kHz range is missing; 173 kHz for the European/Asian 531-1704 kHz range. The older NetSDR also has a 1 MHz, 24-bit limit, but in addition it has two 16-bit bandwidths, 1.3 and 1.6 MHz. 

I sincerely hope that the CloudIQ will be given a similar option.

CloudIQ I/Q bandwidth (NetSDR bandwidth for comparison in green frame)


3 comments:

Anonymous said...

Tack, Bjarne!
Mycket intressant rapport! Och en intressant rx.
Vilken SDR SW tänker du köra med? Perseus har ju fördelen av en dedikera SW och dessutom Jaguar.
73
Arne Nilsson

Bjarne Mjelde said...

Which software to use? Well, for the time being Spectravue is my first choice. I do agree however that the Perseus/Jaguar combo is unbeatable, simply because Jaguar was developed by a MW DX-er, with collaboration from many other MW DX-ers. But the Perseus is old, and every hardware and Windows development makes it increasingly tough to stay compatible.

Ron Liekens said...

Looks nice Bjarne, but if only the CloudIQ could work with Jaguar I would be very keen to buy one. Seems a question was raised from Ilpo to Pieter to write a API that could work with Jaguar but Pieter did not reply to this. If only some could see the benifit to gain from such endavour. Also commercially this will be benificial for RFspace. I for one will be a new customer. I have replaced my Perseus with a Elad FDM-S2 a few years ago, but even Franco makes no efforts to make a API for Jaguar use. The business seems to lack commercial insight I guess.

73' Ron
ON2RON