An update:

I received my FUNcube Dongle! Initial bench test results receiving a strong PICetSat signal (see http://simsat.net/carrollsat/) look good so far to me.

One reluctant evaluator, however, questioned whether the tiny unit was little more than a toy. So, I would like to run some formal tests on it and other receivers at the same time under the same conditions, and then compare results. More testing and evaluation will follow.

In the mean time, one fine group in Texas may have stolen my thunder. See below for an insightful message from Ken N8KH, who uncovered the recent NTMS test results and offered additional helpful comments to us.

But, as an aside about Ken's pre-amplifier recommendation, I found several amplification stages in the FUNcube Dongle itself that are variable and can be easily changed. I will experiment with them before purchasing another satellite-grade low-noise pre-amp. I also have a nice big DCI filter for 145 MHz and another for 435 MHz to insert between the dongle and antenna if and when needed.

Immediately below Ken's message, please see the related links of interest for your convenience.

Did YOU order a FUNcube Dongle yet?

Keep trying. The next sale should be announced on the FUNcubeDongle Web site soon.

Cheers,

Pat N8PK

-----Original Message----- From: Ken Hendrickson [mailto:khendr01@harris.com] Sent: Thursday, May 5, 2011 11:19 PM To: pat@patkilroy.com Subject: MDS & NF Tests (Including FUNcube Dongle)

The North Texas Microwave Society (NTMS) just did some testing of minimum detectable signal (MDS) and noise figure (NF) measurements for common IF receivers, including the FUNcube Dongle Pro [and the IC-910H]. (It was published tonight.)

The FUNcube performed very well. On both 435 MHz and also 1296 MHz it was within 3 dB of the best out there. As you know, 3 dB is just barely measurable in the laboratory with expensive test equipment, and only barely noticeable on the air. Their report/slides:

http://www.NTMS.org/files/MDS_NF_Measurements_IF_Rigs_RevC.pdf

If you want to make up that 3 dB, just add a very good pre-amp to the front end. But be careful, and do not overload the FUNcube with too much signal. You don't want much gain -- only the lower noise figure and enough gain to overcome feedline losses. Make sure to measure dynamic range after adding the preamp, to ensure you haven't degraded dynamic range. But to be honest, 3 dB probably isn't worth it.

Here are some quick and easy rules of thumb:

If you want to double range, you need +6 dB.

If you cut the bandwidth in half, you will add +3 dB of performance (at the expense of time).

So if you need 6 dB, you can cut the bandwidth in half twice. Use slower signaling, and longer integration times at your receiver, and you will have your 6 dB and doubling of range.

The first step to deciding if your FUNcube will really work in your application is to do a link budget. Do you have antenna gain pattern figures? Bandwidths? Power output? Perhaps I can help you out with the link budget.

My gut level feel is that your system will work well, but math is better than a gut feeling.

73, Ken N8KH

PS Please send the address of the Carroll County amateur radio club meeting on Monday night.

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LINKS

FUNcube Dongle Pro http://www.funcubedongle.com/

SoftRock SDR http://www.wb5rvz.com/sdr/ http://homepages.wightcable.net/~g4zfq/Si570.htm

Power SDR http://www.flexradio.com/Products.aspx?topic=PowerSDRv2 http://flexradiowiki.com/frsradoiowiki/index.php?title=Main_Page http://support.flex-radio.com/Downloads.aspx

HP 83712A http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&nid=-5...

MDC High-Altitude Balloon Experiments http://simsat.net/carrollsat/

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Sent: Wednesday, April 27, 2011 11:08 AM Subject: Join a FUNcube Eval

Cross-posted from amsat-dc@amsat.org ...

Yesterday I ordered a FUNcube Dongle Pro from Howard Long, G6LVB, and AMSAT-UK at http://www.funcubedongle.com/ for under $200 USD to evaluate. []

I am evaluating this SDR receiver for dual use on the Amateur Satellites and my STEM project of SimSat, specifically, currently, on quality of reception of my high-altitude balloon experiment PICetSat flight modules. We will fly again this summer.

Part of the FUNcube Dongle Pro technical FAQ is reproduced below, FYI.

I am looking for others who wish to also evaluate the same receiver for whatever one's purpose. Please let me know if you got one or when you get one, and what software you are trying.

Thoughts?

THANKS and 73,

Pat Kilroy, N8PK AMSAT Area Coordinator MDC Area

From http://www.funcubedongle.com/ . . .

Technical FAQ Q. What is the FUNcube Dongle Pro frequency range? A. 64-1,700MHz, although straw poll tests on pre-production units indicate that units can be stretched down to 51.5MHz or so. Upper frequency limit is beyond 2,000MHz. In testing, we have determined that there is a gap between about 1,100MHz and 1,270MHz where the design of the local oscillator VCO, PLL and divider chain in the tuner chip don't provide seemless coverage.

Q. What can the FUNcube Dongle receive? A. The FUNcube Dongle has no restriction on modulation schemes: it is limited only by the application program running on the host computer. As long as the signal fits within about an 80kHz bandwidth, the FUNcube Dongle is capable of receiving the radio signal. So, for analogue reception, as well as narrow band FM and SSB, it is also possible to receive, for example, sound subcarriers for TV broadcast. Similarly for data reception, as long as a data demodulator has been written that will accept standard soundcard quadrature I/Q reception, that will work too.

Q. What is the bandwidth? A. 96kHz is the quadrature sampling rate. Once the ADC's decimation filter skirts have been taken into account, you have about 80kHz.

Q. What applications work with the FUNcube Dongle? A. As well as the forthcoming FUNcube front end application, any application that understands a standard stereo soundcard configured for quadrature, or I/Q, reception should work. Examples include Linrad, Spectravue, Rocky and M0KGK.

Q. What is the sensitivity? A. Each unit is tested for 0.15uV for 12dB SINAD NBFM at 145MHz and 435MHz.

Q. What operating systems are compatible? A. Currently Windows 2000 SP4, XP 32 bit, and Vista and Windows 7 32 and 64 bit have been tested. The sound card element works with Mac OSX and Ubuntu 10.10 32- and 64-bit, but the frequency setting application has not been ported yet. [snip]