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Message |
    
Sandman_69
New member
Username: Sandman_69
Post Number: 1
Registered: 3-2005
| | Posted on Saturday, April 02, 2005 - 6:16 pm: | 
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i have a galaxy 99 and texas star 500. works great unless i use an ext. speaker, then it has a bad squeal. i've tried placement of the speaker,lowering the mic gain,but nothing helps. could someone please help me locate the problem? |
Patzerozero
Advanced Member
Username: Patzerozero
Post Number: 650
Registered: 7-2004
| | Posted on Saturday, April 02, 2005 - 10:12 pm: |
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does external speaker work with amplifier OFF? if no, problem is probably with speaker or jack. if yes-
has it had a talkback added?
is echo on?
high swr's can cause feedback in strange places, as can poor quality coax, particularly from amp to antenna. |
Sandman_69
New member
Username: Sandman_69
Post Number: 2
Registered: 3-2005
| | Posted on Sunday, April 03, 2005 - 9:16 am: |
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talkback came with radio,echo is on,mic gain will take out squeal without the amp on but not much sound is recieved by the road king mic for put out, swr is around 1.4 dont remember what kind of coax but it is clear coated copper about 18 feet long. |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 253
Registered: 2-2005
| | Posted on Sunday, April 03, 2005 - 1:19 pm: |
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Try pointing the speaker away from you. It sounds like your talkback (yuk!) is causing feedback. |
Sandman_69
New member
Username: Sandman_69
Post Number: 3
Registered: 3-2005
| | Posted on Sunday, April 03, 2005 - 6:01 pm: |
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already tried it but to no avail,is it possible that when i had it peek and tuned that my tech. bypassed to many filters? i had to mount the texas star 500 on the dash instead of under the radio because it made a humming sound when i keyed with amp on. |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 255
Registered: 2-2005
| | Posted on Sunday, April 03, 2005 - 9:14 pm: |
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Does it squeal if you throw a deadkey with no modulation? Put the mic against your leg or something so it doesn't pic up any sound, and then key it. If it still squeals then it's RF and you need to use ferrite beads on the speaker wires as close to the speaker as possible.
If it doesn't squeal then it's audio feedback and you either need to turn down the volume or get rid of the talkback.
Your tech shouldn't have bypassed any filters at all. Techs who do that should be avoided because they don't know what they're doing. The filters remove harmonics - not signals on frequency. |
Gumball
Junior Member
Username: Gumball
Post Number: 45
Registered: 10-2004
| | Posted on Monday, April 04, 2005 - 5:02 am: |
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I agree with Racer X, it does sound like an RF issue.
But, if you do what he suggests, and it does not cure the problem, let me add a question - what mic are you using?
If it is stock mic, suggest an RK-56 or Astatic 636, both are good noise cancelling. |
Tech808
Moderator
Username: Tech808
Post Number: 5444
Registered: 8-2002
| | Posted on Monday, April 04, 2005 - 8:32 am: |
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Sandman,
#1 - Turn your talkback down or Off and see if you still have the squeal.
#2 - If you do then move your Ext Speaker farther away for the radio.
#3 - Then if you still have the squeal Turn your Mic Gain Down.
#4 - Also try moving the Texas Star 500 farther away from the radio.
#5 - Check ALL Jumpers, and Coax and what size/type of Coax are you using with this setup?
Any of the above can cause your problem or a combination of any of them.
On a personal note with Texas Star Amplifiers I suggest using a piece of RG8 or RG213 for the jumper from the radio to the amplifier.
Hope this helps,
Lon
Tech808
CEF808
N9OSN
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