Receiving CB Radio with an RTL-SDR Dongle

Back in July we posted a story by Mario Fillipi (N2HUN) who wrote an article about using the RTL-SDR to receive CB radio, and how while the CB radio heyday is over, there are still opportunities for good listening available today.

Recently Mario has posted a new article on where he discusses his CB radio listening hobby further. To listen to the CB band at 26.965 – 27.405 MHz he uses an RTL-SDR dongle together with a ham-it-up upconverter. While an upconverter is not required since most RTL-SDR dongles typically tune down to 24-25 MHz, he finds that using one helps because it can help block out interference from the strong broadcast FM band.  We note that you could also use one of our BCFM Block filters for the same purpose.

Mario notes that recently he noticed the CB band was open during the night. Usually the frequencies that CB radio uses propagate best during the daytime, and poorly at night. But on some occasions it can open up at night as well. He writes that on some occasions during a winters night during a snowstorm he has been able to receive the world on CB, from Europe, the Caribbean and Australia.

CB Band Voice in SDR# with an RTL-SDR and Ham-it-up Upconverter
CB Band Voice in SDR# with an RTL-SDR and Ham-it-up Upconverter
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I heard 3 blokes swearing and arguing recently about which ‘Kodi box’ to buy on 27,781 kHz NFM (not AM as default). Mentioned a pub probably in Bolton (18 miles from me) NW UK using a 33 cm piece of coat hanger. I’ve heard other groups but usually weaker or one sided conversations (25 dB SNR).

I forgot to try the HF modified SDR# which worked well for SWL at 6,000 kHz+ using a long piece of wire out the window, getting China and Romania International mostly. Best with a laptop on battery power. I could barely hear one MW station with filtering. Might be worth a try as I was getting pager interference on CB. Using an RTL 820T2


I also gone through the website, get news that “NPR” discovered by the Harvard Physicist is the world’s tiniest radio receiver. It means the future of CB radio is bright, and near future the CB radio usability increases.


Using an upconverter helps not because of BCB interference, it helps because the dongles as they are are basically deaf on CB/10m.


thanks for Your comment….many have told me the same ‘these v3 dongles are nearly deaf’ and even with a k40 antenna I was unable to pull out one cb’er but then again I cant even get a known frequency to stay in same place stations tuned sudenly SOUND FUZZZY OR JUST ARENT THERE AT ALL SO HARD TO FIND THE CB BAND ‘WHEN YOU CANT TRUST THE FREQUENCY….even ya screen cap dont show You being on a cb channel (26.965/26.975/26.985/26.995/27.005 etc BUT WHEN CANT GET SDR TO FIND THE SAME RADIO CHANNEL YOU ADDED TO YOUR FREQUENCY LIST IT MAKES IT HARD TO FIND STUFF ‘period’ SO WHEN YA READ TO GO FIND AIRPLANES AT THIS FREQ ‘it’s only gonna maybe help You if Your actual in the right place to hear airplanes ‘not that the program has no clue’ I set mine up ‘calibrate’ with 162.555.000 WEATHER REPORT ;zoooom in center an tune in with pps adjustmet til hear it best ‘this ws supposed to make the thing know what frequency is what .. BUT CAN TURN OFF N COME BACK N ITS WRONG ALL OVER OR YOU DONT HEAR THE WEATHER AS GOOD DURING THE DAY TIME but alot of folks agree V3 IS DEAF FOR ME IN SDR SHARP .. dont think ever heard nothing but radio ..WITH HDSDR least had some folks talkin on walkie talkies or ‘something besides jjust radio n yet ‘sve channels n never hear anothr word on ANY …WHEN FIND ALL FREQ IN YA AREA N NOT ONE IS EVER HEARD ‘SOMETHINGS NOT RIGHT’ sad when ya wanna buy a cb radio just to transmit to ‘check with the SDR how off frequency it is .. vs is BEING ABLE TO KNOW ALL BY ITSELF ..SAME AS CB RADIO ‘WE BUY IT’ N IT KNOWS WHERE TO FIND THE CHANNELS ‘right where they suppposed to be ‘ON THE CHANNELS’ SDR OBVIOUSLY ISNT AS EASY


CB’s dead in my corner of the UK, only time i’ve heard anything is the annual truck convoy charity drive.


I haven’t tried this, but a DC-30MHz low pass filter might help also.

I bought one at a ham fest about a year ago for $5.

These were used back-in-the-day to prevent interference to neighbors TV and FM reception.

The logic now applies in reverse.