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 Integrated RTL-SDR and upconverter covers 100kHz-1.7GHz 
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Joined: Sun Aug 26, 2012 2:08 pm
Posts: 1048
Location: Lacey, WA USA
Nooelec and others have built upconverters so that the RTL-SDR USB radios that cover about 54MHz (or 25MHz with the 820T chip) to 1.7GHz can also cover lower frequencies. It is an external add-on. It also bears mentioning that Nooelec has their own modified RTL-SDRs with much more accurate and stable 28.8MHz oscillators.

Edit: There are some kits advertised as 100kHz to 1.7GHz coverage in an all-in-one unit with an SDR soldered inside. Caveat Emptor: they work without an upconverter by bypassing the internal tuner and feeding the RF in the HF band directly to the ADC chip for direct sampling. This is rather more noisy and subject to overloading than the upconversion method.

Kit, $30:
http://www.ebay.com/itm/100KHz-1-7GHz-Full-band-Radio-HF-FM-AM-CW-DSB-LSB-RTL-SDR-Receiver-Kit-Antenna-/142227202653?hash=item211d66e25d:g:i3wAAOSwopRYZIHl

You can also find them built for between $50 and $70.

Review:
http://www.cnx-software.com/2014/08/05/100khz-1-7ghz-rtl-sdr-usb-tuner-receiver-diy-kit-sells-for-33/

I don't see any mention of upgraded 28.8MHz clocks. So it might be worth getting Noelec's upgraded RTL-SDR and putting it into this kit.

Nooelec 0.5ppm RTL-SDR, $21:
http://www.nooelec.com/store/sdr/sdr-receivers/nesdr-mini-2-plus.html

Also available from Amazon with free Prime shipping for the same price:
http://amzn.to/2moiBWn

I'm not sure things will line up, though. The layout of the board is slightly different than what appears in the 100kHz-1.7GHz kit. I already have the above Nooelec 0.5ppm RTL-SDR. So I may order the above kit and see if I can get my SDR to fit.

http://www.nooelec.com/store/nesdr-smart.html

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Steve Greenfield AE7HD


Tue Mar 14, 2017 9:47 am
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Joined: Sun Aug 26, 2012 2:08 pm
Posts: 1048
Location: Lacey, WA USA
It bears pointing out that the upconverter boards work better than the mods that simply bypass the tuner and feed the RF signal directly to the ADC chip.

Using the upconverter, the signal is cleaner and quieter, and can take stronger off-band signals without distorting.

The Nooelec Ham It Up 1.3 upconverter also has an area on it to add integrated wideband noise output, which can be used for antenna and filter testing with the addition of a Return Loss Bridge as discussed here:
https://www.olymega.org/forum/viewtopic.php?f=60&t=354&sid=5fc663a5ace2163bd5d87bbf6760b400

I guess I got an earlier deal that included the parts for the noise source. The current models have the places on the PCB for them with most of the parts installed. From their ad:

Quote:
FREE BONUS: We had space left on the PCB, so rather than waste it we have added a noise source circuit at no additional cost. We have even populated most of the components for you. We have the SMA connector required to complete this bonus noise source circuit available for a small additional fee. Details of the noise source circuit are available with the project documentation.


As I recall, all surface mount parts are installed. I think it was just the SMA connector and a jumper that had to be soldered in.

Fortunately, it is open source:
https://github.com/opendous/Upconverter1v3

Nooelec 0.5ppm upgraded RTL-SDR on Amazon for $21:
http://amzn.to/2npR346

Nooelec Ham It Up 1.3 converter board, extends frequency coverage down to 100kHz. Uses a 125MHz conversion frequency so it no longer ends up in the middle of the FM radio band. . $45
http://amzn.to/2nBHkXK

Blue aluminum case for the Ham It Up 1.3. If you add the noise source, you'll need to drill one additional hole for the SMA connector, and if you wish to be able to turn it on and off, another for a switch.
http://amzn.to/2lXLYTk

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Steve Greenfield AE7HD


Tue Mar 14, 2017 11:38 am
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