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Cobra 2000GTL Receive needle adjustment. How?

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414 Machine
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Cobra 2000GTL Receive needle adjustment. How?

Post by 414 Machine » Sunday, 28 February 2010, 12:36 PM

My needle for my cobra 2000 is VERY stingy, I have my neighbor 3.1miles & less away from me & its only giving me 5-6 on the needle & guys less than a mile are only hittin me at 7-8, you have to be in my driveway to make it at or above 9lb signal. Any help is mucho appreciated. I just need to know what to adjust to bring that needle up & be a lil' more accurate.
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Re: Cobra 2000GTL Receive needle adjustment. How?

Post by TheCBDoctor » Sunday, 28 February 2010, 18:10 PM

Hi 414 Machine

The adjustments for the receive meter is VR-1 and VR-2. Each of these is used for AM and SSB respectively, but they must be adjusted together because one affects the other. With 100 micro-volts injected into the radio at 30% modulation you must adjust VR-1 for 7 S-units. You then do the same for VR-2 on SSB without any modulation.

You then repeat the adjustment for AM, and then again for SSB until the meter reads correctly for both modes. This is a time consuming process that requires the proper test equipment. There is no standard for what an S unit is. Try and adjusting VR-1 while listening to a known station; when you are happy with the meter movement I would leave it alone. Check sideband to make sure the needle does not peg. If it does you may need to turn down VR-2, which means you may need to adjust VR-1 on AM again.

Did you ever notice that commercial radios do not have a signal meter for transmit or receive? That is because they are not needed. If you can be heard or can hear others then the radio is working. The meter just looks nice and serves no real purpose except when "Hunting" some one down to Pin their coax. I guess that's reason enough :icon_e_wink:

Good luck,
Best Regards,

Rick, The CB Doctor


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Re: Cobra 2000GTL Receive needle adjustment. How?

Post by 414 Machine » Sunday, 28 February 2010, 18:25 PM

Thank you once again there Doc, much appreciated. I'll be picking your brain more & more as the days go on as I'm trying to fine tune & go thru this radio to put her back to somewhat normal. it looks great, talks ok I guess? Only DK 2watts swing 7-10watts? These radios aren't known to be super powerful but I know they can do more than this one is I do believe.

While I got ya here on this thread could I bother ya to answer something for me please sir? I went to change the bulb for my "Receive" light under the channel display, only to see that someone had clipped the main power lead & it was just hanging off the bulb out of the rubber grommet, I don't know alot about these radios yet so I ask, where do I connect the power lead to get the bulb to only power on after transmit, there was no trace or sign of where this was clipped from so I have no idea where to attach it. Kinda bothers me knowing I have a light out & I cant fix it on my own but as I stated I dont know these boards yet. Any help is always, greatly appreciated Doc, Thank you in advance!
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Re: Cobra 2000GTL Receive needle adjustment. How?

Post by preacherman » Monday, 01 March 2010, 6:57 AM

Hey 414...
Much depends on the meter you are using. If it is a peak reading meter,
you should be able to get 15w or more out of that 2000. Some say 25w
but those are few and far between If your meter is an average reading
meter, then 7-10w is pretty good and all you can expect to see out of that
unit. Keep workin' on it...I have one that will never leave....well, at least
not cheaply :biggrin:
Preacherman
"Preacherman workin' this mudduck mercury. Topside, Land O' Lincoln"



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414 Machine
Duckplucker
Duckplucker
Posts: 145
Joined: Monday, 18 January 2010, 6:18 AM
Radio: RCI 2990
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Name: Tim
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Re: Cobra 2000GTL Receive needle adjustment. How?

Post by 414 Machine » Monday, 01 March 2010, 8:13 AM

Yea I hear ya preacher, I just inserted a photo of it in the post titled "What have you recently acquired for new radio gear?" post locatedat this link, lemme know what ya think. viewtopic.php?f=8&t=26657&start=200
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