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Message |
    
Tech808
Moderator
Username: Tech808
Post Number: 7089
Registered: 8-2002
| | Posted on Tuesday, September 13, 2005 - 9:34 pm: | 
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This Topic has been moved here from the Open Area of the Copper Forum.
Lon
Tech808
CEF808
N9OSN |
Deptuydog
New member
Username: Deptuydog
Post Number: 9
Registered: 5-2005
| | Posted on Friday, September 09, 2005 - 1:46 am: |
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I have a problem with a mic squeal on a ranger 6900F150, using a astic power mic model 575 m6. I also run a texas star 667v with a wilson 5ooo mag mount. Radio and amp are grounded to the battery with a # 6 gauge wire and the postive wire is also # 6 gauge hook to the battery. Radio case is grounded to the battery and the amp case is also. Radio has been tuned to dead key starting and 1 1/2 watt. Mic setting is at 50% on slide control and radio will not get past a 10 oclock postion on modulation knob. Doesn't matter if radio is operating by itself or with amp on. If i turn mike up or radio modulation up it will squeal. I had this setup in a 1972 chevy pickup for a year with no problems and i just installed this same setup in a 2005 gmc pickup,and i just can't figue out the problem. Check all the normal stuff mic battery , grounds, coax, iam stump, would appreicate any ideas .Radio and amp really worked great together in other pickup, just can't seem to figure this one out. |
Musky
New member
Username: Musky
Post Number: 4
Registered: 8-2005
| | Posted on Friday, September 09, 2005 - 7:45 am: |
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Try grounding the mic to the radio. Find a place on the mic and run a small wire to the chassis of the radio. This might work. Does it squeal if you put your hand on the radio while keying? |
Dave1
Junior Member
Username: Dave1
Post Number: 23
Registered: 9-2005
| | Posted on Friday, September 09, 2005 - 9:31 am: |
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if your radio has talkback try moving the mic away from the radio
or if you had the modulation limiter taken out of your radio putit back in |
Deptuydog
Junior Member
Username: Deptuydog
Post Number: 10
Registered: 5-2005
| | Posted on Friday, September 09, 2005 - 10:22 am: |
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It does not squeal if i touch the radio but it will squeal if i touch the mic to my body while it is keyed up. Would i hook the ground wire to the shield in the mic cord then to the chassis of the radio? thanks for your imput. |
Dale
Intermediate Member
Username: Dale
Post Number: 232
Registered: 12-2002
| | Posted on Friday, September 09, 2005 - 12:04 pm: |
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ive found radios with talkback dont work wekll with power mikes.but id try turn the power mike all the way down then bring the mike gain on radio this is more proper and reduces back ground noises in mobile.if that dont work shout off the talkback all together cause its actually feedbacking thru your talkback.not thru your mic |
Cornbrown
New member
Username: Cornbrown
Post Number: 4
Registered: 7-2005
| | Posted on Friday, September 09, 2005 - 6:49 pm: |
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Try turning the talk back off. |
Deptuydog
Junior Member
Username: Deptuydog
Post Number: 11
Registered: 5-2005
| | Posted on Saturday, September 10, 2005 - 12:53 am: |
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So far i have tried all of the sugestions you have all given me and no success, about all that happens is the squeal will go away but the modulation drops way down. Oh by the way i didn't have the modulation limiter cut out.I haven't tried grounding the mic to the case yet but i will this weekend. i'll let you know if that helps. Again thanks for all the sugestions i really do appreciate everyone trying to help. |
Vanillagorilla
Intermediate Member
Username: Vanillagorilla
Post Number: 201
Registered: 4-2005
| | Posted on Saturday, September 10, 2005 - 1:31 pm: |
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I say get rid of the ground from the radio that goes to the battery. Cut it as short as possible and ground to the body of the vehicle near the radio. My radios squealed bad and this helped A LOT. Ground the chassis of the radio as well. A screw off the rear holding the cover on is fine.
I don't see a problem using the same ground point as the radios DC ground as long as you keep it under 1ft. A 6" Ground strap works very good comming from floor of vehicle (or roof panel..whichever your radio is closest to) then use small hardware (1/4-20 nut and bolt)to ground DC and chassis ground to it with crimp connecters soldered on the ends of "up to" 10guage wire. Total length AS SHORT AS POSSIBLE.
As if it shouldn't be already...be sure the battery NEG post is grounded WELL to the body and or chassis of the truck.
If your SWR is a little higher than you like you'll see it improve after this as well. Bottom line....if all else fails lose the power mic. I know you don't wanna hear that! 
Good Luck!
Hank '905
CEF 559 |
Deptuydog
Junior Member
Username: Deptuydog
Post Number: 12
Registered: 5-2005
| | Posted on Sunday, September 11, 2005 - 2:14 am: |
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Thanks again for the sugestions, I will give your sugestions a try Hank. Your right I don't want to lose the power mic, but if the squeal out modulates the mic then i guess the power mic really will not do me any good. Thanks again, I'll let you all know how things work out.
Dave |
Dale
Intermediate Member
Username: Dale
Post Number: 233
Registered: 12-2002
| | Posted on Sunday, September 11, 2005 - 10:40 pm: |
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you tried just turning off the talkback
shouldnt drop modulation just wont hear yourself
anymore.is the mic wired correctly?thought id
ask |
Unit199
Intermediate Member
Username: Unit199
Post Number: 157
Registered: 8-2003
| | Posted on Monday, September 12, 2005 - 6:39 am: |
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You might give this a try. Take a 4700ohm resistor and put on audio line in mike. Make sure it is in series. If that does not work, then take a .001 or .01 mfd capacitor(disc) one leg to either side of resistor and other leg to shield wire. I hope this helps.
HARVE
Unit199
CEF210
KB0YVK |
