feedback(NOT) w/desk mic only??2000gtl...update....

[slim cdx285]

if i use any powered desk mic w/my 2000 i get feedback w/the dynamike turned up.doesn't do this w/stock hand mic or

a powered hand mic! what gives man,gotta have my desk mic!!

i appreciate any and all ideas as to where to start! thanks.

Slim

FYI

i already checked the mic board and it's not shorting or touching anything.bad cap somewhere??

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=slimcdx285>slim cdx285</A> at: 5/20/04 10:54 pm

 

[slim cdx285]

if i use any powered desk mic w/my 2000 i get feedback w/the dynamike turned up.doesn't do this w/stock hand mic or

a powered hand mic! what gives man,gotta have my desk mic!!

i appreciate any and all ideas as to where to start! thanks.

Slim

FYI

i already checked the mic board and it's not shorting or touching anything.bad cap somewhere??

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=slimcdx285>slim cdx285</A> at: 5/20/04 10:54 pm

 

[nomadradio]

Re: feedback w/desk mic only??2000gtl

Two possibilities come to mind.



First, does the desk mike have at least five wires in the cord? The 2000GTL has TWO, count'em TWO pins connected to ground. Pin 2 should connect ONLY to the shield on the audio wire. Pin 4 should connect ONLY to the transmit/receive switch in the mike and NOT to anything else inside the mike. Keeping those two grounds separate is a big deal. If the mike was made with only four wires, only ONE of them is ground. Besides, that ground is connected BOTH to the audio circuit AND the transmit/receive switch inside the mike. Using a four-wire power mike on a 2000GTL will result in some level of compromise. Those two ground circuits really need to remain separate.



If in fact your mike has the two separate grounds, one for audio and one for the T/R switch, check inside the mike plug to see that the bare shield connected to pin 2 does not rub against the metal surface of the plug's metal shell. Normally, that mike plug is supplied with a short length of clear plastic sleeve that goes inside the shell of the plug. It serves to separate the "chassis" ground from the bare ground shield on the audio wire. If they touch, this creates what is commonly called a "Ground Loop" between the microphone input circuit and the rest of the radio. Tends to cause audio feedback on transmit.



Anyway, you didn't say what kind of mike you have. That could be an important clue.



73

</p>

 

[nomadradio]

Re: feedback w/desk mic only??2000gtl

Two possibilities come to mind.



First, does the desk mike have at least five wires in the cord? The 2000GTL has TWO, count'em TWO pins connected to ground. Pin 2 should connect ONLY to the shield on the audio wire. Pin 4 should connect ONLY to the transmit/receive switch in the mike and NOT to anything else inside the mike. Keeping those two grounds separate is a big deal. If the mike was made with only four wires, only ONE of them is ground. Besides, that ground is connected BOTH to the audio circuit AND the transmit/receive switch inside the mike. Using a four-wire power mike on a 2000GTL will result in some level of compromise. Those two ground circuits really need to remain separate.



If in fact your mike has the two separate grounds, one for audio and one for the T/R switch, check inside the mike plug to see that the bare shield connected to pin 2 does not rub against the metal surface of the plug's metal shell. Normally, that mike plug is supplied with a short length of clear plastic sleeve that goes inside the shell of the plug. It serves to separate the "chassis" ground from the bare ground shield on the audio wire. If they touch, this creates what is commonly called a "Ground Loop" between the microphone input circuit and the rest of the radio. Tends to cause audio feedback on transmit.



Anyway, you didn't say what kind of mike you have. That could be an important clue.



73

</p>

 

[slim cdx285]

Re: feedback(NOT) w/desk mic only??2000gtl...update...

thanks nomad.that's making sense now that i started

playing around w/it! i'm trying to use the cobra dynamike ultra

that originally came w/the 2010 and it only has 4-wires!

i'm gonna have to change out the 4-wire for a 5-wire and figure out how to isolate the other ground at the mic switch.

i'm still open for any ideas as a shortcut tho!LOL!!!!

actually i'm trying to wire up 2 of these;one for me and the other for a friend of mine who just got a mint,virgin 2000.

these are wired as original as far as i know.below is the pin-out.(my silver eagle works fine BTW.)

i did try anothers suggestion,ran a jumper to ground the mic to the radio.it helped,but didn't eliminate the static.AND;it's

static i'm hearing,not TX audio feedback,as i originally

thought.the static is only present w/the radios mic gain at

12 o'clock and above.the mics gain pot has no affect at all!

thanks sir.

Slim

1-red

2-shield

3-blue

4-n/c

5-white

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=slimcdx285>slim cdx285</A> at: 5/20/04 10:53 pm

 

[slim cdx285]

Re: feedback(NOT) w/desk mic only??2000gtl...update...

thanks nomad.that's making sense now that i started

playing around w/it! i'm trying to use the cobra dynamike ultra

that originally came w/the 2010 and it only has 4-wires!

i'm gonna have to change out the 4-wire for a 5-wire and figure out how to isolate the other ground at the mic switch.

i'm still open for any ideas as a shortcut tho!LOL!!!!

actually i'm trying to wire up 2 of these;one for me and the other for a friend of mine who just got a mint,virgin 2000.

these are wired as original as far as i know.below is the pin-out.(my silver eagle works fine BTW.)

i did try anothers suggestion,ran a jumper to ground the mic to the radio.it helped,but didn't eliminate the static.AND;it's

static i'm hearing,not TX audio feedback,as i originally

thought.the static is only present w/the radios mic gain at

12 o'clock and above.the mics gain pot has no affect at all!

thanks sir.

Slim

1-red

2-shield

3-blue

4-n/c

5-white

</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=slimcdx285>slim cdx285</A> at: 5/20/04 10:53 pm