CB Radio Nocking out USB Ports?

[Michael Carlson]

I had problems with my CB Radio disconnecting my USB ports on my laptop and I know Tony Laubach had this same problem with his CB Radio. I am not sure if the problem is where I mounted it or if I have the settings up to high but it disconnects the USB ports when I try to broadcast over a channel.

That is the CB Radio and I currently use a Dell Inspiron 8600 as my chase laptop. If anyone has any suggestions about how to fix this problem that would be awesome.

 

[John Erwin]

I had problems with my CB Radio disconnecting my USB ports on my laptop

Ahh, you're probably in for a big hassle trying to fix this since there can be a number of things that contribute to this. Essentially what is going on is that the RF from the CB radio is being induced into the laptop via it's cables or other means and then causing this particular problem (but you already knew that).

Some stuff to try;

- relocate the radio or laptop if possible. A few inches can make a big difference.
- re-route the CB radio's coax and power cables.
- don't connect the CB radio to internal wiring, go direct to battery if possible.
- re-route any USB cables or other cables on the laptop.
- don't use a mag mount *** this is a big one. One of the major causes of EMI problems like this. Try switching to a different mount (ie a lip mount or other mount that provides a better connection to the vehicle chassis.)
- hopefully you're not using a glass mount antenna... that would be bad!
- Check your radio/antenna to see if you have a high VSWR.
- Try a different antenna.
- Use split beads on all computer wiring, and on the power wiring of the CB.
- check to see if the CB chassis is grounded properly.
- check to see if the car's battery ground cable is in good shape.

Try an experiment; power your laptop from it's own battery and see if this happens. Then do the same powering your laptop by whatever other means you have (ie do you use an inverter?). If the problem only occurs when you are using external power (by an inverter for instance) than we know that is how the stray RF is getting into the laptop. Might help when combined with other steps above. In extreme cases a filter can be constructed to remove RF from the power cable but that should be a last resort.

There could be a number of other things to check but I would start with this list.

Good luck!

 

[Tim Samaras]

Michael,

Are you running a magnet mount antenna? Its quite possible that stray RF may cause some radiation inside your vehicle due to an ungrounded antenna..causing an overcurrent on the +5 volts on the USB port. Also, be sure that your radio is well grounded (12 gauge or better wire tied to the back chassis of the radio and to a good chassis ground either on the dash on floorboards. Don't trust the low side of the power cable as a ground. Some radios float the low side (minus side), and are not connected to chassis ground. Check with a voltmeter to ensure that your ground is good.

Good physical separation between the radio (and coax cable) and laptop/USB cable is a good idea..and if the problem presists--try wrapping the offending USB cable around a ferrite torroid core near the USB connector..

Good luck!
Tim

 

[Rob Wadsworth]

Michael,

Are you running a magnet mount antenna? Its quite possible that stray RF may cause some radiation inside your vehicle due to an ungrounded antenna..causing an overcurrent on the +5 volts on the USB port. Also, be sure that your radio is well grounded (12 gauge or better wire tied to the back chassis of the radio and to a good chassis ground either on the dash on floorboards. Don't trust the low side of the power cable as a ground. Some radios float the low side (minus side), and are not connected to chassis ground. Check with a voltmeter to ensure that your ground is good.

Good physical separation between the radio (and coax cable) and laptop/USB cable is a good idea..and if the problem presists--try wrapping the offending USB cable around a ferrite torroid core near the USB connector..

Good luck!
Tim

I'd have to agree with Tim S 100%. First, be sure that you have the antenna matched to its lowest SWR. Then, do the choke route, as there is probably current on the cable jacket that needs to be dealt with - the choke should do it. Separation inside a vehicle may not happen, as it is still too close quartered to the radio and just might not be practical. John E's idea of insuring that all electricl equipment in the vehicle using ferrite on cabling is good insuance too. After that, it just might be a trade-off of use and need for the moment. The full ferrite treatment is on-the-money...

 

[cdcollura]

Good day,

This can be an RF issue or even a power issue via RF interference.

I have a VHF radio that causes my USB ports to disconnect on my laptop every now and then, but only on high power at 55 watts. My antenna is mounted permanently to my vehicle and grounded via PL-239 connector (for easy removal of antenna at car wash or parking garage).

There is a number of approaches to fix this, but I will name a few here...

Try to properly ground your antenna, or even have an antenna that radiates ABOVE the top of the vehicle, and not through it (such as a roof mount instead of rear bumper mount).

You might want to filter the incoming power to your laptop's invertor and / or power supply (if using that). I found simply moving my laptop's power brick helped this issue alot - It was picking up RF!

Only use the amount of RF power you need to transmit. I work 5 Watts about 90% of the time and it's just fine. I rarely do any DX stuff so simply powering down might help as well.

Also (Thanks Tim) ... A properly matched antenna is paramount (SWR). You want to send OUT the RF power, not reflect it back into you, your vehicle, and any sensitive electronics. You may also want to "tune" your antenna with a SWR meter for this.

These are just a few ideas off the top of my head.

I remember having an HP Pavilion that would lock up with the screen scrambled if I transmitted on 55 high power on my VHF!

 

[Tony Laubach]

Thanks for the reply guys... I've had a similar problem with my CB radio and USB ports which is unfortunate given that we typically like to use these for non-HAMS in close-proximity chasing when a group of us in different cars head out. I'll be anxious to gives these solutions a try when I get back to Denver.

Michael, if these work before I get to it, lemme know!

 

[Michael Carlson]

Thank you everyone for replying and with the great advice. I will be doing tune ups to work out the kinks before next season comes. Thank you again!