Need help!

[Bronze15]

Moved my equipment from one truck to another, now getting major squeal when I key mic. Power straight from battery, grounded inside to bar under glove box, Wilson 1000 mag mount antenna.

Hey Bill...

Check your grounding and turn down your mic gain.

Also check that the mic is properly connected and no loose wiring.

Bombero

[MDYoungblood]

Hello Bronze15,
Welcome to the forum. Do what Bombero said, good sound advise. Check the coax to see if you kinked it, check the SWR, high SWR will make the radio squeal. If the radio has talkback, turn it off. Is it a power mic, a dead battery could be it. There is all kinds of possibilities, give us a little more info like make of radio. Might try another ground/negative location, that bar might not be connected to the body.
I always ask new members to post an intro in the "Welcome to the Forum" topic, http://www.cbradiotalk.com/viewforum.php?f=89 , so other members can say "Hello", thanks.

3's

Greg

[yota167]

Are you running an external speaker?

Also, RUN THE GROUND TO THE BATTERY.

[Bronze15]

Thank you all for the replies.

Did find that the base of the Wilson 1000 mag mount was coming part inside and was very rusty.
Purchased a new base and while trying to set Swr's radio grumbled and squealed while calibrating meter. Swr's all over the map. Had mic gain at half, rf power 1/4

Running connex 4300 hp with 636 l Astatic mic installed in a wooden box that is strapped in behind console for now in a 2015 ford explorer. Could paint on this vehicle be causing a ground issue on the mag mount?

Was always told to keep ground wire as short as possible, but willing to run directly to battery if that is what is best.
Have about 12 feet of number 12 stranded running from battery, is that heavy enough. Have friend running same radio, turned all the way up on a cig lighter plug

In mean time, hope I didn't fry radio.

Thoughts on where to go from here???

While buying new mag base, did have radio checked out and had issues on test bench, when tech took it to his work bench, did find some loose solder joints inside and he fixed those, then radio checked fine on his bench. But again, when attempting to set Swr's thing went nuts.

Thank you all for assistance. Really miss having this operational.

[yota167]

Interesting you mention the inside of the Wilson mag mount going bad. I pulled mine out to let a friend use and decided to take a look inside it as it's been over 5 years since I've had it in use. The conductor was separated entirely and the ground had corroded through. Thing was a mess. Re spliced and soldered it back better than new but man I had to take a flap disc wheel on the angle grinder to knock the rust off it all and shine it up so my ohm meter would even read ground to ground. There was major resistance on the meter before I cleaned it up.

If I were you I'd try running ground to battery and see if your squeal calms down. Also try placing the mag mount in center of cab roof, then try a few inches from the very back of the roof. Moving the antenna can sometimes help get the ground plane to work with a mag mount better so it'll tune a lil lower.

[231]

Thank you all for the replies.

Did find that the base of the Wilson 1000 mag mount was coming part inside and was very rusty.
Purchased a new base and while trying to set Swr's radio grumbled and squealed while calibrating meter. Swr's all over the map. Had mic gain at half, rf power 1/4

Running connex 4300 hp with 636 l Astatic mic installed in a wooden box that is strapped in behind console for now in a 2015 ford explorer. Could paint on this vehicle be causing a ground issue on the mag mount?

Was always told to keep ground wire as short as possible, but willing to run directly to battery if that is what is best.
Have about 12 feet of number 12 stranded running from battery, is that heavy enough. Have friend running same radio, turned all the way up on a cig lighter plug

In mean time, hope I didn't fry radio.

Thoughts on where to go from here???

While buying new mag base, did have radio checked out and had issues on test bench, when tech took it to his work bench, did find some loose solder joints inside and he fixed those, then radio checked fine on his bench. But again, when attempting to set Swr's thing went nuts.

Thank you all for assistance. Really miss having this operational.

The reason you want to always run both power leads to the battery is to prevent ground loop. The battery acts as a capacitor and won't let that happen. Of course nobody can ever say for sure whether you'll have a ground loop or not. Some do some don't...when someone is having trouble, it's a good place to start. I always run both leads to the battery when possible...even on a barefoot radio. If it's not possible you do the best you can. But having a short ground or short leads doesn't always prove effective nor helpful.

Does the mic have a battery? If so, replace it. A bad battery will cause the mic to squeal (especially on Astatic mics).

Secondly, turn the mic gain off and power down to a lower setting (if variable output) and check the standing wave with a dead carrier...no audio or squeal. Transmitting audio will cause all kinds of problems with meter calibrations. Hopefully you are using an external meter, too. If the standing wave is okay (1.5:1 or less), new battery in the mic, crack the mic gain open some and see where it begins to squeal. If it's constant, I'd guess you have a bad mic connection. If it's good and only squeals when you talk and you have talk back, shut the talk back off. Also, any noise toys you may have might be a problem too (that includes roger beeps).

I can think of other possibilities but those are the easiest that come to mind.

231

[Bronze15]

Again, thanks for the responses.

Non powered mic so no battery to replace. It is only a couple months old, talk back off and mic gain all the way down as well as rf. still can't even calibrate the external meter. Mag mount is in center of roof.
Will try to run ground out to battery to see if that helps.not easy in this vehicle. Anyone know where there is a grommet to run thru on a 2015 explorer?


Thanks again.

[yota167]

Look at the picture I posted of my Wilson 5000 mag. Open yours up and take a picture. If you have an ohm meter you need to verify that you don't have a break in the coax somewhere or internally at the magnet. You are getting some great help here.

Make sure the center conductor isn't touching anything other than the pl259. The tolerances between ground and hot inside the mag mounts can be close and if they touch you'll get a short spiking your swr.

[MDYoungblood]

The squeal is coming from the high SWR. You might have a grounding problem but you need to focus on the SWR issue first. If you have bought a new magnet mount and used the old coil it sounds like the problem is with the coil, they have been known to get fried too, possibly the whip. Measure the whip of the antenna , it should be about 62" minus maybe an inch if it was tuned before, shorter than that it has been cut way too much and that needs replacing. Best suggestion here is to get a complete antenna.

3's

Greg

[yota167]

Yep, squeal must be from feedback of reflected power from a short in his antenna system. Bad coil, bad coax, bad connector. I'm with u MD, guy needs to try a new antenna with new coax. Also pull the lid on cb to make sure the radios so239 panel jack is properly grounded and soldered to the cb board and chassis.

An OHM METER would go a long way to helping him diagnose where his issue is or where it isn't.

[231]

I agree...if you can't even calibrate the meter it's an indication that you've lost your antenna counterpoise connection. In this case, it's the capacitive coupling of the mag mount. Focus on fixing that first and your squeal problem will likely be gone.

231

[Bronze15]

Ok, now let the fun begin, this is anew mount and coax, took the radio to another shop, checked out fine, they checked antenna, said it is fine, they heard the rumbling and squealing and said it was due to voltage drop. Tonight checked all connections, ran ground to battery, and still same rumbling.


Willing to purchase new coil and stinger if needed, but the shop said antenna is fine, 1.1 on their meter.


This is going to drive me crazy.


Thoughts?????

[yota167]

Do any of you guys think the TX( red) and the RX (black) wires in the microphone could be touching eachother or maybe the rx is broken at the mic pin? Not sure if this would cause a squeal but OP you should try a different microphone to rule out this.

Guess the last option is installing a big FERRITE right at the mic jack that can take a wrap of two of cord.

[Windwalker]

Hi
Sounds to me like the antenna might have issues but. You said you ran the ground from the bar under the glove box. That to me is not good enough.
Running the ground as far as the battery does not thrill me either.
I would go through the firewall with the ground straight to the engine block. I would then continue the same ground wire to the battery.
You should also make sure you have a grommett in the hole you run the wires through. Make sure your connections are clean and tight.
Going through that firewall you need an inline fuse for the Pos wire between the battery and firewall. That will prevent a fire.
Check your jumper to the external meter and inspect all your PL259 connectors. If they are the crimped type that may be a problem.
Hopefully this will help !

WW1

[Bronze15]

Thanks for the help ww1. I did change the ground to a seat bolt that I sanded bothe finishes so as to make sure I was metal to metal. No difference,. Did redo all connections just to make sureve everythingn checked out. and for all that have been kind enough to help, the squeal isn't the same as you would expect from say mic too close to speaker with talk back on, more of the rumbling sound staying steady, if that makes sense.

The tech at the sop mentioned that may need to downgrade to the 3300hp as it was less finicky to power issues. Can anyone comment on that?
Thank you all again for attempting to assist!!

[Windwalker]

OK so you got the power and ground covered. Your connections are tight and you still have the issue at hand.
Next I would look at the radio or mic. I would also remove the jumper and external meter and see what happens.

WW1

[Bronze15]

Sorry, should have mentioned that after the shop tested the radio, ( not mic, will change micsto see what happens) and the antenna, I did not put the meter back in line. This is all happening now, with no meter. Didn't feel the need to keep testing antenna or Swr's after the shop checked and said antenna fine, they had an adjustable meter that checked antenna only by the frequency and found antenna to be set at 1.1. Will check the mic, only thing left that hasn't been checked. It is only a couple of months old, but you never know.

Thx

[Rabbit Ears]

Yes yota167. Just had my radio squeal too.... it was a magmount K-40.

Checked the unit.... WOWWWZERS!! *MY STOOPID!*

It was the center conductor of my coax that was broken off inside of the magmount. Repaired the thing *slappptt!* (oww..)

Works great now..... low SWR.

Corrosion on a 25+ year old unit.

[yota167]

OP, you need to make this clear; you do NOT have a squeal problem, you have a "grumbling" problem....or a rumbling problem. Right? WHERE is the rumble or grumble coming from? The truck speakers? Sorry if I missed those details.

I had a similar situation in a big truck install with a stryker 490. The coax was radiating stray RF Into the speakers in the form of a wugh wugh wugh sound. I was able to eliminate it although not entirely by re routing coax away from the trucks speaker power wires. IMO, hindsight maybe using a foil shielded coax like lmr240 would have been best .

I'm sorrry we are throwing so many options at you but some mobile installs can be very challenging, br I've found that there is almost always a solution to a problem if your equipment your workin with is ok.

[Bronze15]

The rumbling is in the cb speaker, not the sound system. The mag mount is brand new.


Here is something very interesting, have a friend with the exact same radio, for giggles we hooked his up to my setup, used my mic, power connection and radio connection. His radio worked great.

Had 2 shops check my radio and said it was fine.


Any thoughts on this?

Thanks all.

[yota167]

The rumbling is in the cb speaker, not the sound system. The mag mount is brand new.


Here is something very interesting, have a friend with the exact same radio, for giggles we hooked his up to my setup, used my mic, power connection and radio connection. His radio worked great.

Had 2 shops check my radio and said it was fine.


Any thoughts on this?

Thanks all.

Check to see if r249 or tr32 has been cut or removed entirely. Compare your boards components in those locations to your buddies. Maybe some hack removed ALL your modulation limiting circuits.

[halfwatt959]

Just for giggles ccheck to make sure all the board screws are tight and ground straps aint broken. Also make sure so239 [ant connection] is tight as well. Who knows but Ive had radios work great on the bench but have similar symptoms in the vehicle and found loose board screws to be the culprit.