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Freebird
Posted on Wednesday, January 22, 2003 - 8:16 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I am running a cobra mobile on a power pack and when i talk there is a low hum in my radio. It only does when i transmit.When i touch the metal part of the mic connector or the pl 259 connector it goes away then when i take my finger off the hum comes right back.what is this anyway?
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Carolinagold
Posted on Wednesday, January 22, 2003 - 8:43 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Freebird. To me it sounds like a lose shield wire in your mic or on the mic plug.
Thats just my $.02
But it could be somthing else
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Ironmask
Posted on Wednesday, January 22, 2003 - 8:56 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Freebird,

I am not a tech but I think you have a ground problem. Does the power pack have a three prong plug? Are you grounded from case to case and house ground. You said you touch the connector and the hum goes away. You are acting as the ground.
Hope this helps!
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307
Posted on Thursday, January 23, 2003 - 8:21 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Actually it sounds to me like the power supply is not a really regulated supply OR it is to small (current). What kind and what amp rating is it?

307
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Freebird
Posted on Saturday, January 25, 2003 - 12:30 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

well it is a regulated power supply but its only a 3 amp one.but for some reason its doing making that sound anymore.
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307
Posted on Saturday, January 25, 2003 - 9:35 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thats why...3 amps is pushing it ..you need at least 5 amps...

307

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