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)

Wednesday, July 01, 2015

New Toy

A new radio is ready for testing. I was lucky enough to be among those who got the first batch of 100 or so receivers, and I will look forward to testing it the coming weekend. For anyone not familiar with the CloudIQ, here's the story:

More as it happens.

Recent Verifications

(Well, not so recent... since March actually)

WGVA Geneva NY 1240
WAEB Allentown PA 790
WMAL Washington DC 630
WMLM St. Louis MI 1520
WMEL Cocoa Beach FL 1300
WDAE Tampa Bay FL 620
WRTA Altoona PA 1240
WTVL Waterville ME 1490 (tnx OJS!)
KNEU Roosevelt UT 1250

Friday, March 20, 2015

An Alternative Way To Power Your Perseus

While the stock, switching 5VDC power supply for the Perseus is among the quieter ones, it doesn't perform adequately in an extremely low noise environment. Linear 5V power supplies aren't abundant, and they often come at a price.

Unlike the RF Space SDR-IQ, the Perseus draws too much current to be powered from most  PC's USB 2.0 outputs which are usually limited to 500 mA. However, with the advent of the USB 3.0 standard, this has changed. The Perseus typically draws 700-750 mA, while a standard USB 3.0 output will deliver around 900 mA - more than enough for a Perseus.

This needs a proper power cord with a USB connector in one end and a 2.5 mm connector in the other. It is perfectly feasible to build your own, and there are several DIY instructions on the net. I wanted to avoid potential problems related to poor soldering skills though, and then I found this on Ebay:

It's a custom made power cable for the Perseus. It sells from the USA for a nickel short of $20, + shipping. I've bought three of these, and they work perfectly. The seller claims they are "roughly 6 feet", which is roughly true as the last cable I bought measured in at 5.75 ft/175 cm.

A cable like this is an absolute must have if you want to do an outdoor DX session. You can power your Perseus from a laptop or a battery pack, and use the laptop to run the Perseus from a different USB port.

All my three Perseus in Kongsfjord are now powered from PCs and they seem to cope well.

This particular item will pop up if you do a "perseus sdr" Ebay search.

Admittedly there are literally hundreds of Chinese-made USB-to-2.1 mm cables on Ebay, with prices as low as 0.99 USD/EUR including shipping. I haven't spotted any 2.5 mm cables though.

Whatever you do, always check the polarity of the connector before you power up the Perseus. Mistakes do happen.

Saturday, February 28, 2015

February 2015 Verifications

CBT Grand Falls/Windsor NL 540
CBNA St. Anthony NL 600
WATR Waterbury CT 1320
CJLO Montreal QC 1690
HJIP BBN 1590 AM, Bogotá 1590
WRNI Providence RI 1290
KXLO Lewistown MT 1230
CHRF Montreal QC 980 (Canada #215)
KBMW Breckenridge MN 1450
WYSL Avon NY 1040
WOND Pleasantville NJ 1400
WAMG Dedham MA 890
CHML Hamilton ON 900
WERC Birmingham AL 960 (North America #1100)
KCLK Asotin WA 1430
WKNY Kingston NY 1490
WSLB Ogdensburg NY 1400 (#50 on 1400)
WATN Watertown NY 1240
Radio Capital, Lima Peru 1470 (thanks Arvid Husdal)
WTWD Plant City FL 910 (thanks OJS)

Saturday, January 31, 2015

January 2015 Verifications

KRKC King City CA 1490
KXPA Bellevue WA 1540
WKOX Everett MA 1430
WXKS Newton MA 1200
WMMV Cocoa FL 1350
WNTN Newton MA 1550
WCMC Wildwood NJ 1230 (tnx Jarmo Patala)
WMID Atlantic City NJ 1340
WRKO Boston MA 680
KRZR Fresno CA 1400 (tnx OJS)
WVEI Worcester MA 1440
WTAG Worcester MA 580
CFCB Corner Brook NL 570
KTIP Porterville CA 1450 (tnx OJS)
KCMY Carson City NV 1300
WAXY Miami FL 790
WCTC New Brunswick NJ 1450
WPIE Trumansburg NY 1160
WNBP Newburyport MA 1450 (USA #900)
WROC Rochester NY 950
KMYC Marysville CA 1410
KOBO Yuba City CA 1450
WMNN Pompano Beach FL 1470
WKBK Keene NH 1290
WDMC Melbourne FL 920

Thursday, January 01, 2015

December 2014 Verifications

KICD Spencer IA 1240
KBIZ Ottumwa IA 1240
KINO Winslow AZ 1230
CKMK Mackenzie BC 1240

Monday, December 01, 2014

November 2014 Verifications

WQSC Charleston SC 1340 (facebook) – “graveyard” station # 200.
KCIK Kihei HI 740 (tnx OJS)
KLER Orofino ID 1300 (pdf)
KBAM Longview WA 1270 (tnx ABU)
KUOM Tumwater WA 1340
KGIW Alamosa CO 1450
KGGS Garden City KS 1340
WBUC Buckhannon WV 1460
WNDE Elkins WV 1240
WMCR Oneida NY 1600
KUIK Hillsboro OR 1360
KPIO Loveland CO 1570
KEWE Kahului HI 1240 (Hawaii # 30, on test mode at low power)

Friday, October 31, 2014

October 2014 Verifications

KKAN Phillipsburg KS 1490
WAOS Austell GA 1600
WNDA New Albany IN 1570
KVSV Beloit KS 1190 (Tnx OJS)
KDCC Dodge City KS 1550 (Tnx ABU)
Rete Italia, MacKay QLD AUS 1611
KLFJ Springfield MO 1550 (Tnx ABU)
WGAM Manchester NH 1250
KVSH Valentine NE 940 (Tnx OJS)
WBEX Chillichote OH 1490
WNSW Newark NJ 1430
KEYE Perryton TX 1400
KGWU Uvalde TX 1400
KKOW Pittsburg KS 860
KAJO Grants Pass OR 1270
WIRY Plattsburgh NY 1340
KCRC Enid OK 1390 (Tnx ABU)
KCMN Colorado Springs CO 1530
KMBI Spokane WA 1330 (facebook)
KOKL Okmulgee OK 1240
KCNW Fairway KS 1380 (Tnx OJS)

KNOT Prescott AZ 1450 (Tnx OJS)

Friday, October 17, 2014

KONG24 - Day Seven

Final evening! OJ and TJ leave on Saturday morning, so we were hoping for some really hefty signals last night and today.  Not so....

Overnight monitoring of the MW band on the 310 beverage. Sun symbol illustrates local sunrise and sunset times. Sunset times for North American cities indicated to the right. Red line on the time scale illustrates the total strength of the stations in the band (10-kHz stations only)

Only the 04:00 UTC full hour provided any signals of interest, but on the other hand they weren't all that interesting after all. Stations noted were KGYN-OK 1210, KPOW-WY 1260, KGOE-CA 1480. Maybe more interesting stuff will materialise as we check the recordings.

OK weather, light to fresh breeze, mostly dry and +1C.  

Dinner-wise we always save the best meal to the last day, so today was reindeer tenderloin day. The meat was accompanied with fried mushrooms, potato paste and woked carrots, scallions and shallots. With these excellent ingredients, we opted for an exquisite Italian red, the 2007 Gattinara. For dessert we enjoyed dark chocolate pudding with vanilla custard. An eternal favourite. The picture of the day honours the main course:

I will leave Kongsfjord for Vadso later on Saturday or early Sunday, so this is the last KONG24 blog post, unless exceptional conditions appear tonight. Thanks to all who had the patience and interest to follow us in our Arctic Endevour!