Friday, January 17, 2014

RTL-SDR Adapters and Pigtail Cables

MCX to BNC pigtail cable (bottom) - BNC to UHF adapter (top)
Thanks to Ron VA7VW for providing this information for me and the other NORAC club members as we prepare our bulk order of some RTL-SDR's.

Ron is a 'VHF and Up' enthusiast so his expertise is appreciated. 

The RTL2382U / R820T USB DVB-T dongle is 24 MHz to 1.850 GHz

So let's look at some common Amateur Radio RF connectors

N type connector
  • 0 - 18 GHz
  • insertion loss is less than .15dB @ 10GHz

BNC type connector
  • 0 – 4 GHz
  • insertion loss is .2dB @ 3 GHz

UHF type connector
  • 0 - 300 MHz
  • insertion loss is 1 dB @ 300MHz
  • As you can see it's good for HF but not really suitable for a very very wide portion of the RTL-SDR’s frequency range 300 MHz - 1.85 GHz)

MCX to SMA is also a very common pigtail/adapter combination on these dongles with very acceptable low loss.

So with lots of cool activities on the full range of the RTL-SDR we need connectors and cables with suitable low loss characteristics.

As Ron says... At VHF and up, every dB counts. 

So with that in mind I suggest that we increase the variety of pigtail cables that we supply to NORAC members with the RTL-SDR.

As mentioned in the original quote we still provide the MCX to BNC pigtail with the BNC to UHF adapter (picture at top of this post).

But we should all ALSO consider some or all of the following.

MCX to N female

MCX to N male

MCX to SMA female

And since a couple of the NORAC members have already expressed interest in an Upconverter, you will absolutely require the pigtail below to connect the RTL-SDR to the NooElec Upconverter board.

MCX to SMA male - This is a required cable for a RTL-SDR to Upconverter connection.

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