Need help with feedback on CB Radio

[Steve L]

Hi all - if anybody can help me with this problem, or knows of somebody who could help me, I would really appreciate it.

Problem. I have Nolan helmet, with wireless Bluetooth in it (Ncom). I have recently had a Honda CB installed in my 2012 Goldwing. When I plug in the Cable to my activated bluetooth helmet (cable supplied by Nolan for this purpose), everything works fine, except that when I transmit on the CB, I get a very loud feedback noise that drowns out my transmission.

If I place the helmet on the front seat of the bike, I can transmit without the feedback. As soon as I raise up the helmet, the feed back starts when I hit the transmit button. If I move the helmet towards the CB antenna while transmitting, the feedback instantly gets worse. If while transmitting and getting the loud feedback I wrap my hand around the CB antenna above the black filter in the middle of it, the feedback instantly disappears and I can transmit ok!

I don't know anything about CBs and radio, but it seems to me that when I hold the antenna it is filtering out the interference from the bluetooth. So my question is, does anybody know how I could permanently filter out the interference from the bluetooth helmet? I asked my wife if she would hold onto the antenna when we go riding, but she declined - lol!

Steve L.

[MikeB]

It sounds to me like you are getting RF feedback into your Blue Tooth headset. In a normally wired circuit, you could put a .001 microfarad capacitor between the MIC hi and MIC lo wires to shunt the interference to ground. With a bluetooth, I have no idea how to help. You might try the capacitor anyway to see if it will work.

Have you tried the CB and intercom system with a normally wired headset?

[Viking]

When they installed your radio, did they put the magnetic clip on piece on the rear control line? If not, this might be causing the feedback. Other than that, if it were me, I would be contacting Nolan, or the supplier of the bluetooth equipment

[virgilmobile]

Sorry mate...In your case with the equipment you describe it will never happen.
The system was engineered for hard wire interface.
RF energy is getting into your wireless receivers.If you shield it from the CB you also shield it from the rest of the system.

The only way to eliminate the impact of the transmitter on the helmet would be to relocate the antenna.
A custom made antenna that is below your horizontal plane of the helmet(see the pix).....almost on the ground.
The drawback is then the range of the transmitter is greatly reduced.
Unfortunately I am not aware of a off the shelf one,however it may be worth looking into.
A antenna needs height to be able to reach out and must stand vertical. This restricts the antenna on the bike to 10-12 inches(inside the side pack) and also dramatically reduces the range.
If I had to guess,a custom antenna or hidden antenna inside the side pack may reach a city block away.

[WingAdmin]

This is a pretty simple problem. Your CB is putting out ~4 watts of RF. Your Bluetooth module works at around 1 mw - 1/1000 of a watt. So your CB, even though it's on a totally different frequency, is working with 4000 times the RF signal that your Bluetooth module uses. If the Bluetooth module has insufficient shielding or poor design such that the wires attached to it act as an antenna, the 4 watts of RF radiating from your CB antenna will actually induce an electrical signal inside your Bluetooth module. Because CB is amplitude modulated, the signal induced in the Bluetooth module is an exact replica of the audio being transmitted over the CB - which is then fed from the Bluetooth module to the CB, where it is transmitted again, and there you have your feedback loop.

I have a similar problem with a 5-watt transmitter I have here at home - when I key it up, the paper shredder in my office turns on - the result of poorly designed/poorly shielded electronics.

You can try wrapping foil tape (look in the heating/cooling section of your hardware store - normally used for sealing ductwork) around your Bluetooth module and perhaps some of the ancillary wires. It may help, it may not.

[cbx4evr]

Ya!! What he said.^^^^^

Holy crap you guys use big words.

[vtxcandyred]

When I read "NEED HELP WITH FEEDBACK ON CB RADIO" I believed he was refering to someone who was talking about his citizens band radio.????? heh,heh,heh.

[Steve L]

Thanks to everybody who offered suggestions on how to solve the problem. Pleased to report that I have solved the problem, and it was not too difficult. A couple of simple ferrous clamp-on filters was all it needed, but the secret was exactly where to place them! A little bit of trial and error got it. One on the antenna cable, under the seat. The other on the cable that plugged into the Honda audio cable. Interestingly it did not work with the clamp on the Honda side of the cable under the cubby hole on the left. Had to locate it on the helmet cord just before it plugged into the Honda cable - simply attached it to the side of the bike trim with a couple of pieces of Velcro so it doesn't bang around. Any other position for the filters or just using one didn't work! So now have a fully functioning CB!
Steve L.

[ogilly0753]

Interesting. When I had the Bikemp3 CB I had transmission problems with my Nolan helmet N90 & Nolan N-Comm Bluetooth. I was told that the plug-in on the helmet would receive but not transmit. I have since changed to wired J&M audio kit for my helmets, but my wife misses the bluetooth. She likes not having a wired cable connecting her to the bike.

[redial]

Because CB is amplitude modulated, the signal induced in the Bluetooth module is an exact replica of the audio being transmitted over the CB

It's a shame that you North Americans are sticking to that AM (Ancient Modulation) for your CB, and havent moved into the late 20th Century and gone to the higher frequency and FM (Fancy Modulation) of the rest of the world. It took a couple of years, but everyone, including the trucks, have gone over from the (so-called) VHF (Very High Frequency) of 27Mhz (Mega Hertz - no not rent-a-car) to the UHF (Ultra High Frequency) where things are quieter, not so much 'snap, crackle, and pop', and more channels are available. The latest specification allows for a nominal 80 channels.

I generally ignore all the information when North Americans talk about CB, as it has little relevance to the rest of the world. I have a UHF set in my car and listen to it on long journeys, but around cities and towns, you usually get the motor-mouths playing their kind of music, trying to demonstrate their IQ is bigger than their shoe size, or trying to motor-mouth their way through the profanity lists. One of the locals here calls all of the transporters paediphiles, which is time for me to turn it off. Some people do not realise that with trust comes responsibility - if I trust you to talk reasonably on the radio and you comply, then I wont be the one responsibile to kick you up the butt.

Here endeth the sermon for today.

[WingAdmin]

I would LOVE for the FCC to abandon AM CB and move to FM. Increased sound quality, range of more than the mile or two of CB, better separation...

We do actually have a FM "CB" system, known as FRS (family radio service), but I believe FCC regulations limit radios on this band to handheld units - nothing built into a car. Power output is also fairly limited - but certainly works better than an equivalent CB, and much smaller as well.

[FRANK ALEXANDER]

Hey guys im having the squeel in my cb problem .Mine only does it when i try and trasmitt out .I can hear everyone else fine . i have a bike mp3 cb unit on my 2002 Goldwing . Can anybody help me . ( please )

[ogilly0753]

What type of helmet intercom system you usieng?

[FRANK ALEXANDER]

What type of helmet intercom system you usieng?

Its a ICM OR IMC

[wjnfirearms]

Yes, the AM band transceiver is about as antiquated as the AM radios in a car, but until bandspread is opened up for public unrestricted use, it won't happen here. In fact, not long ago, the FCC mandated changes in the FM bandspread to go to narrow banding. This is where the channels were tightened up so there can be more channels available to business and public safety. It made a lot of two ways obsolete. Good for the radio manufacturers, bad for the users as they were forced to buy new radios if the ones they already had couldn't be modified. This also affected users of the 800 band.

You know, I'm not sure why there has never been a mobile FRS or GMRS radio made. Maybe it is by design. Shame.

Going to FM has it's drawbacks. Most radios on the FM band used these days are using repeaters. These retransmit the signals at an increased level so they can be heard over greater distances. Most, more than before, are duplex. The difference between simplex and duplex repeated radios are that simplex transmits and receives on the same exact channel. Duplex transmits on one frequency and receives on another. The repeater transmits the signal received from the radio on the second channel. They are activated by the radio transmitting an inaudible private line signal so use on any given frequency is restricted to the licensed group or agency. This means that radios committed to a duplex channel have to have two different frequencies put into a given repeater channel, one to transmit to the repeater, one to receive the signal. FM is affected by anything that obstructs line of sight where AM is much less affected. Years ago when FM non repeated simplex radios were used by police, you couldn't hear the cars talking if they were a significant distance away from each other and forget about walkie talkies. The base could usually hear them, but it made car to car communication iffy at best. Not a good situation to be in when the SHTF. The FRS and GMRS radios are FM simplex non repeated. Anyone that has used them knows that they are affected greatly by topography and buildings. Still, FM has its advantages.

[ogilly0753]

The problem I had was with my Mpbike CB and Nolan NComm Bluetooth. Nolan's setup allows for input into helmet but does not allow for CB transmissions. I removed the NComm and installed wired J&M intercom mic set for our helmets and that cured that problem. The other issue I was having was the volume on the Mp3bike CB volume maxed out and could not get any more volume. I have corrseponded with Pete and they are going to correct the volume issue with their next software update but could not get a firm answer when to ship my CB for the update. WIngstuff helped me through this process and exchanged for Honda OEM CB and I have not had any issues. I found out that someone else had the same volume issue from another Gold WIng rider and he swapped to Honda CB and been fine since. I have a CSC trike and the other guy had a two wheeler. To me your issue reminds me of something is not properly connected or maybe some feedback.

[ogilly0753]

Frank have you connected Pete at Mp3bike concerning the CB squeal?

[FRANK ALEXANDER]

Frank have you connected Pete at Mp3bike concerning the CB squeal?

Yeah i sent it back to him and he updated the software in it ,but it didnt solve anything.Im wore out with this problem .he even gave me a new main cord that goes under the seat.

[ogilly0753]

I hate to say this but I would get rid of the Bikemp3 CB. I did not have any luck and I will not use Nolan Ncom Bluetooth until something changes. I know the Honda CB is expensive but it cured my probelm.

[radionut]

After reading this thread something nobody has mentioned is adjusting SWR of the antenna. Typically if the antenna is not adjusted for minimum SWR the RF from the transmitter that is reflected by a improperly tuned antenna travels back towards the radio and into the electrical system of the bike. Typicaly the first indication is distorted audio on transmit.

For those people discussing why they haven't adopted GMRS ( the higher power version of FRS ) is a design limitation by the FCC where they mandate the antenna be directly connected to the transceiver. Radio Shack is the only company to get around this by putting the transceiver in the bottom of a mag mount antenna with a control head speaker mic inside the vechicle. Considering this it should be very possible to make a transceiver that would have a directly connected antenna that would tuck into the corner of the trunk where the CB antenna mounts, and use the controls of the bike to operate it. ( this is a big hint for the makers of the aftermarket makers of CB's.

[redial]

Radionut,
Is this the sort of thing you are looking for?

http://www.gme.net.au/products/radio-co ... ios/TX3340

[radionut]

Well, something like that would be a big improvement. It is just that Honda had control of who could use the communications protocol between the audio controller on the 1800 and the radio unit in the trunk pocket, It would now seem that is gone as aftermarket providers are now producing units to replace the cb and still using the audio controller to run it.

The CB in your link is not approved for use in North America, there is a small spectrum in the UHF band that is approved for use here but it is only 22 channels and 1watt max power. That said, with a gain antenna it would still out perform a 5 watt cb.

It would be intreating to see if the communications between the mic and the radio in the link you sent would be compatible with the audio controller of the 1800, I would doubt it, but you never know, or the manufacturer of that unit might produce a model that is if presented with a demand for it.

As a ham radio operator I am more interested in mounting a dual band radio that would be capable of more than what this radio would offer. and if the Goldwing community were to go to a FRS style radio I would be there with them. Until mother Honda realizes just how pathetic CB radio is and starts to offer a better choice we will likely be stuck in the dark ages. I mean really who else can charge 500 bucks for a 45 dollar radio and then have us believe it is a luxury to be able to talk to another bike 500 feet in front of you?

[wjnfirearms]

I wouldn't see that happening until two things change. First, for those that don't know, you have to take a test to get licensed as an Amateur Radio Operator, or as it's known, a HAM. You have to pay for the "privilege" and if you don't study the material or have past radio knowledge, you won't pass it. I cannot see people doing this just to have them as an alternative to a conventional CB. Then, until the demand is there to make it profitable for Honda to offer them , I don't see that happening either. There was a time that you had to get licensed to operate a CB, but there was no testing involved, just a nominal fee.

[redial]

The reason behind the change in Oz was because the AM CB operates in the 27Mhz area, and that is a useful frequency for other things. With a good antenna, and good atmospheric conditions, you can successfully operate this 5watt radio over thousands of kilometres (or two thirds as many miles). People in Oz were regularly working other CBers in the USA .

By pushing the CB community to the UHF band, they effectively removed the really long distance (aka skip) from CB, which to a CB is really not necessary. If you are driving along in your vehicle, you are really not interested in the fact that there is a speed trap on a road 500 miles away. So the UHF FM radios achieved a better signal, shorter distance, but still workable upto five km on the road, and stop splashing all over the "call channel" with rubbish that is not of interest.

They have also narrowed the bands of late, so that there are now upto 80 channels (although some are reserved), which is easily useable by most operators of these FM radios. With the US restriction to handheld radio for FRS (or direct antenna attachment), you seem to be stuck in a time warp. I will send an email to the manufacturer and see what comments they have.

[radionut]

I had a look at the Industry Canada website to see if any of the frequencies of the Oz CB spectrum was used, and out of 80 channels, only one is used in Canada. it is used in several locations across Canada, but just one channel. I suspect that would be enough to kibosh the entire spectrum though.
Still, it might be and idea to put a bug in their ear and possibly get them thinking.
73
RY