Thursday, December 18, 2014

RTL SDR Problem/Caution

I'm a huge fan of SDR after discovering it around 6 months ago and these £6 RTL SDR dongles that are all over eBay at the moment are a great way to get started. They're a great value SDR dongle that coupled with SDR# in my opinion is a very powerful tool and since then my scanners have sat switched off in my shack.

I decided recently that I'd get a second SDR dongle from eBay so I could run one on my PC for pager and digital decoding and the other on my laptop for analogue VHF and UHF monitoring. So I got onto eBay and bought the absolute cheapest one I could find. It came in about a week and was identical to my existing dongle right down to the packaging. Happy days! Or so I thought.

I plugged the dongle into the laptop and decided to give it a test to check everything was ok but when I clicked play in SDR# I received an error message saying cannot access RTL devicde. So I decided to reinstall all software/drivers etc and try again but the same message kept appearing. The exact same happened on my desktop PC too.

So I decided to do some searching around on Google and all results pointed to software issues but there was no difference between the dongles and all my software was correct. I plugged my old dongle back in and received no signals which worried me a bit as I use my SDR all the time. After racking my brains for 30 minutes I noticed the faulty dongle had knocked my RF gain to 0Db!

I gave it up as a bad job and decided to take the dongle apart to see if there was any difference in hardware inside that could be causing the fault and saw that the board inside seemed corroded! Now, I'm no electrical expert so it could be that either the board inside had fried when I plugged the dongle in, or the unit has been exposed to moisture but the pictures below show the damage that is causing the fault.

The soldering on the board seems to be of a very low standard too which makes me think that some manufacturer in China is cloning these boards for various eBay sellers to distribute onwards in bulk hence the poor quality. Who knows!

Anyhow, the dongle was only £6 and I received a full refund after contacting the seller so no harm done really but just a word of warning when buying these dongles on eBay or anywhere else. Sometimes the cheapest one isn't always the best one. Go for a dongle that's around £8-£10 and save the hassle.

Thanks for reading!

73's, Lewis M3HHY.

Manchester, UK.

1 comment:

  1. Hey Lewis,

    That stuff on the second PCB is flux residue, most likely left when the board was reworked.
    It doesn't usually cause any problems, but if it needed rework at the factory there could have been something else that at fault that isn't so easily visible.