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 Post subject: Basic alignment question on a CB
PostPosted: Oct Tue 05, 2021 11:24 pm 
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Joined: Nov Sun 30, 2014 4:20 am
Posts: 18
Location: Jackson, New Jersey
I know this is probably not the best place for this, but I will try anyhow. Looking to do an alignment on a newer Cobra 29 cb. On the flowchart, they don't show a dummy load for the antenna. I'm thinking I will blow the final out the way it is pictured. Also they don't really say in this factory manual where to hook up or couple the signal generator. I haven't looked for a Sams yet, but I think this is too new. Thoughts??
Bill A.


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 Post subject: Re: Basic alignment question on a CB
PostPosted: Oct Wed 06, 2021 1:05 am 
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Joined: Nov Sat 07, 2009 11:37 pm
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Location: Sayreville, NJ 08872
Assume the Wattmeter is really a dummy load/wattmeter.
The Cobra 29 series, and there are a number of models, has been around for probably 50 years.
What is it you're trying to do?

Based on the service manual info, receiver alignment for RF and IF sections is done with the Signal Generator coupled to the antenna input. I would also suggest putting a 50 ohm dummy load on the antenna input when doing receiver alignment.

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 Post subject: Re: Basic alignment question on a CB
PostPosted: Oct Wed 06, 2021 1:11 am 
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Location: Mountains of Mourne. Ireland.
Sams covered the earlier model 29GTL in Photofact CB Radio Series CB-217
Should be close enough for servicing purposes.
You may have trouble locating a copy as this model was sold by the bazillion. lol


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 Post subject: Re: Basic alignment question on a CB
PostPosted: Oct Wed 06, 2021 1:45 am 
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Joined: Nov Sun 30, 2014 4:20 am
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Location: Jackson, New Jersey
Thanks for the replies. This is a newer made in China version, 2008 I think. I picked up a few of these and just wanted to see if they were in specs. All transmit & receive with another cb. This is more of learning project then anything else. Better to learn on these $5 radios then something expensive!
On the dummy load, could I put this on the antenna side of a directional couple I would use for My scope?

Another question, one section of instruction for PLL portion states; TX mode, no modulation, channel 40. use dc volt meter to adjust L19. I'm confused here, because if you key the mike, wont you always have modulation? we're not using the signal generator in this step, where you could control the modulation. Thanks!!
Bill


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 Post subject: Re: Basic alignment question on a CB
PostPosted: Oct Wed 06, 2021 5:09 am 
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Joined: Nov Sat 07, 2009 11:37 pm
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Location: Sayreville, NJ 08872
allert wrote:
Thanks for the replies. This is a newer made in China version, 2008 I think. I picked up a few of these and just wanted to see if they were in specs. All transmit & receive with another cb. This is more of learning project then anything else. Better to learn on these $5 radios then something expensive!
On the dummy load, could I put this on the antenna side of a directional couple I would use for My scope?

Another question, one section of instruction for PLL portion states; TX mode, no modulation, channel 40. use dc volt meter to adjust L19. I'm confused here, because if you key the mike, wont you always have modulation? we're not using the signal generator in this step, where you could control the modulation. Thanks!!
Bill

Dummy load replaces the antenna.
If you don't talk into the mike, there is no modulation.

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https://www.manualman.com


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