Topic: Feedback from speakers in CB (Read 3851 times)

Sklywag · « **on:** March 25, 2007, 09:33:19 PM »

Hadn't used the CB for several months. Went to use it today and I am getting feedback from the speakers, the CB is coming over the speakers, very loud. Others can hear me just fine so the CB is working but the feedback is really bad. The only think I have done is the latest firmware update to the radio. Any ideas before I call HD?

Thanks

Sklywag · « **Reply #1 on:** July 03, 2007, 11:31:56 PM »

Here is an update on my problem after 4 trips to HD and the factory getting involved. 1st I had to remove all electrical modifications after the 3rd trip into HD or the factory wouldn't get involved.

The factory agreed that it was a very strange problem and agreed to replace the radio, they swapped the radio & it still did the same thing. Now that really stumped everyone.

Finally the one thing I thought of that they never picked up on was that I moved the passenger headset connector from hanging under the seat to being mounted in the left side under the armrest, with the speaker & controls, like the 07's & by following the instructions that were here on the site.

Guess what, it is significantly better, but not gone.

The other thing I found in troubleshooting is that if I cut off all the tie wraps on the right side of the MC under the seat & free up the antenna cable I can control the feedback by moving the antenna cable around. That makes more difference than moving the passenger headset connector.

Has anyone had antenna cable issues?

I just went and bought an SWR Meter and am going to continue troubleshooting but for now I can again use the CB without the feedback with the passenger connection pulled back out of the left side by the speaker.

Sklywag · « **Reply #2 on:** August 05, 2007, 09:14:04 PM »

The latest in my pursuit of solving this issue.

I pulled off the fairing, made an adapter cable and hooked up the SWR meter. WOW, that was a shock, pegged the SWR. Ok, start digging, very high SWR indicates a shorted antenna cable, ok. So I run a temporary antennal cable from the CB right to the antenna bypassing the loading coil. Not bad got it down to 2.5 to 1, but I'm sure it could be better. Did a couple other tests that indicated that the antenna was considered electrically short, so no way to lengthen it without the loading coil.

I start to look at the loading coil and was suprised at what I saw. For thouse of you that are technical. The center conductor of the antenna cable is soldered to the middle winding of the coil, the top of the coli is connected to the antenna and the bottom of the coil is connected to ground. Now the coil is only 6 turns of # 10 gage wire around a plastic core, effectively the CB output is just shorted to ground, thus the hight SWR. I removed the ground, hooked up the original cable and was about 3.2 to 1. Next I connected the loose antenna cable ground to a good ground. 1.8 to 1, getting better. Now I don't know why but I removed the metal mounting bracket from the loading coil. now the SWR is about 1.3 to 1. I really don't know why it makes that difference, I put it on & off a couple times.

Bottom line, I now have a 1.3 to 1 on channel 19 and about 1.5 to 1 at both ends. Real nice. The loading coil is just hanging loose under the Tour Pack Liner at this point.

I would love to know if anyone else has had an SWR meter on the 06 SEUC with the leather tour pack and what your results are. I konw it's asking a lot but I would love to have a picture of your loading coil, remove the nut that holds it to the tour pack bottom, turn it upside down and take a pic of the metal mounting area at the coil mount area so I can see how yours is wired.

Guess what, didn't fix my CB transmission causing the squealing out through the speakers.

I keep digging.

I will make a long story short, I have discovered that my SE has a grounding problem. I have solved the CB Speaker issue by installing a plastic bolt to attach the CB physically to the Radio. The plastic bolt isolates it physically from the radio as it sits on rubber feet on the top of the radio. Simply changing this bolt make the issue appear or go away.

I have taken some measurements and I do not have a good consistent ground throughout the MC. I had 16 ohms from the negative battery terminal to frame ground, and that is a 6" cable. I removed the cable from the ground stud, cleaned the lugs & the stud and now have 0 ohms. I have 45 ohms from the battery negative to the ground connections inside the fairing.

I will now be visiting the HD dealer again with my new info as i can't find the faulty ground.

Radarlv · « **Reply #3 on:** November 02, 2008, 01:43:39 AM »

Did you ever get the problem fixed?

Sklywag · « **Reply #4 on:** November 02, 2008, 11:02:04 AM »

Yes I did. HD could not solve it however, big surprise.

It turned out to be the Coax Cable, some where in it's length it must have been damaged even though continunity chcked good & I was able to get a decent SWR match.

Once I replaced the cable, no easy job, and did a new SWR match everything was fine.

Radarlv · « **Reply #5 on:** November 03, 2008, 06:21:59 PM »

I see that you made an adaptor for the SWR meter, I got a SWR meter from Radio shack and was going to use it back at the ant, but it will not work that way. Do you need the adaptor at the front under the fairing? How har is it to make the adaptor?

Sklywag · « **Reply #6 on:** November 03, 2008, 06:39:30 PM »

1st you can't measure SWR at the antenna, the cable has too much effect on the results, it must be measured at the back of the radio.

The adapter at the radio is easy, the connection to the Radio is "BNC" so at Radio Shack you buy a short piece of RG58 one PL259 connector to attach to one end of the cable and a female BNC to go on the other end, this cable should be no more than 12" in length, this will connect the SWR meter to the CB. Then you need a PL259 to BNC male adapter to connect the antenna cable to the other side of the SWR meter.

If you tell them at Radio Shack that you need to adapt the SWR meter into a BNC connection they can help you with the parts.

If you have any trouble I can post a couple pictures.

Don't be surprised if you peg the SWR meter when you hook it up, I have done several of these now & the best factory SWR I have seen was about 2.4 to 1.

The last one I did I had to cut 9" off the antenna to get it down to 1.1 to 1 It started with the meter pegged.

A suggestion from experience:
If the SWR meter pegs, start cutting the antenna off in 1" increments till you see the SWR start to come down, once it starts coming down cut smaller amounts off, you can't add it back :-).

If you go to http://www.firestik.com/Tech_Docs.htm there is a section on setting SWR which can be very helpful.

I have switched to the No Ground Plane Firestick System, it outperforms the HD antenna hands down. I run one 3' black antenna that does both the CB & Radio.

Radarlv · « **Reply #7 on:** November 05, 2008, 11:35:53 PM »

A pic would be great if you have time.

Radarlv · « **Reply #8 on:** November 05, 2008, 11:37:14 PM »

Better yet when is your next trip to Vegas, Ill buy the beer.

Sklywag · « **Reply #9 on:** November 06, 2008, 10:34:23 AM »

Actually I come to Vegas often on business. It is always spur of the moment and typically one day. Email me your contact info, if I see I am coming for an overnight I can easily bring stuff with me. bwillison at akaresults dot com

I will take a pciture this weekend

Bill

Sklywag · « **Reply #10 on:** December 12, 2008, 09:54:27 PM »

I promise I will get a pic this weekend.

Radarlv · « **Reply #11 on:** December 14, 2008, 09:11:08 AM »

Ya
I just figured you forgot about me , you know what they say on this web site all the time.

Dont forget about the beer next time your in Vegas.

Sklywag · « **Reply #12 on:** January 22, 2009, 11:28:27 PM »

Yes, I know, I promised this weeks ago. Better late than never. Several posts to show the pics

Sklywag · « **Reply #13 on:** January 22, 2009, 11:29:34 PM »

CB Radio connector side

Sklywag · « **Reply #14 on:** January 22, 2009, 11:33:59 PM »

Antenna Side connectors

Sklywag · « **Reply #15 on:** January 22, 2009, 11:35:43 PM »

With adapters in place

sportygordy · « **Reply #16 on:** January 23, 2009, 10:26:19 PM »

Sklywag,

just curious, did you measure the output power with your SWR meter? Does the CB radiovput out the norm 4 watts?

Sklywag · « **Reply #17 on:** January 23, 2009, 11:37:56 PM »

I have measured 4 different radios and they were all less than 3 watts. 2.4 to 2.9 was the range.

SERK3 · « **Reply #18 on:** January 24, 2009, 10:33:37 AM »

I have no expirence with CB's on a bike but years in a big truck, If your CB has a mike gain on it try turning it down a little, most of the time that will stop feedback thru speakers. Make sure the coax is not touching (tie wrapped) to any electric wires. Get a true CB ant. not one that works with the AM/FM CB. Steel ant. is better but will be hard to find one without a huge center load. My suggestion is get a Frances fiberglass ant. very little if any thing you will have to do but install it on your bike, just make sure its grounded good. As far as finding a stock CB doing the max. 4 watts, good luck, you can take it to a CB shop and have it TURNED UP to maybe 6-8 watts but what is more important is how much it will SWING, Eample i run a CONNEX 3300 HP, deads keys 7-7.5 watts swings about 50, the swing is what lets you reach out there and touch someone. I have my CB set up to where i can flip a switch where it dead keys 2.5 watts swing appox. 27, then turn the kicker on and will do around 550 watts. Like i said don't know if any of this works on a bike or not, but i have always run a BIG radio and works for me, forget about the kicker part on a bike it would melt the bike down.

sportygordy · « **Reply #19 on:** January 24, 2009, 12:17:35 PM »

Quote from: sklywag on January 23, 2009, 11:37:56 PM

I have measured 4 different radios and they were all less than 3 watts. 2.4 to 2.9 was the range.

I looked at the loading coil on mine last night.. WOW,, it's junk, no wonder these CB's don't work well. If you are really serious in using the CB radio it wouldn't take much to improve the antenna system. Skywag, did you measure the power at the radio port and power meter terminated? Just curios if the radio is putting out 4 watts and the loss is through the junk antenna system?

Sklywag · « **Reply #20 on:** January 24, 2009, 08:51:52 PM »

No, unfortunately I did not have a 50 ohm termination to measure it into a correct load. I have replaced the entire system on my SE with a Firestick designed for no ground plane. Since MC's do not have a good ground plane, not enough meta surface area on any MC, it is worth going to a no ground plane system. I saw no difference in power from when I had a 3.5 to 1 match, original antenna un tuned, 1.1 to 1 tuned match on the original antenna or the 1.1 to 1 match I have with the Firestick.

I am using the Firefly, 3' antenna & the matched cable from Firestick. Then trimmed the antenna via its tuning stud that is built in to a < 1.1 to 1 match

It works quite well, very clear but still quite limited range with the no ground plane & the low power.

sportygordy · « **Reply #21 on:** January 24, 2009, 10:25:22 PM »

did you bypass the stock loading coil? I betcha the loading coil is killing the output power. Also, the Firefly, 3' antenna has a loaded coil built into the antenna. These loaded coils kill the output power at the antenna load. It would be interesting to check if the radio is putting out the normal 4-watts at the radio output. I would think it does, since the radio is made by Midland. Midland produces quality stuff.

Author Topic: Feedback from speakers in CB (Read 3851 times)