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Mobilepainter
New member
Username: Mobilepainter
Post Number: 1
Registered: 5-2004
| | Posted on Monday, May 31, 2004 - 5:40 pm: | 
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I have recently got back into CB'c, driving a truck all day does that to you. I have bought a Cobra 146gtl which has the clarifier unlocked already. I would like to increase the output power as much as possible on AM and SSB. I have ordered a Cobra highgear modulated power mic, for $20 + shipping and handling I do not expect stellar performance from it but rather a slightly better sound for now until I can get a better mic.
So..... can someone please give me information on increasing the wattage on this unit or direct me to a website or a book that pertains to my needs and/or wants.
Any input is appreciated. Advise on a good modulated mic would also be great.
Mobilepainter, AKA Lagwagon, CB ch 8 & 17 NW Washington state. |
Tech808
Moderator
Username: Tech808
Post Number: 2543
Registered: 8-2002
| | Posted on Monday, May 31, 2004 - 6:12 pm: |
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Mobilepainter,
FIRST LET ME WELCOME YOU TO THE COPPER FORUM!
COBRA 146GTL:
MODULATION: ADJUST ~ VR-5 or Remove TR-29
AM POWER: ADJUST ~ VR-10
SSB POWER: ADJUST ~ VR-6
Hope this help's.
Lon
Tech808
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Mobilepainter
New member
Username: Mobilepainter
Post Number: 2
Registered: 5-2004
| | Posted on Wednesday, June 02, 2004 - 12:04 am: |
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Will adjusting VR~6 cause any clipping or distorion? Also what exactly will cutting TR-29 do for modulation? And...... if I cut TR-29 and/or adjust VR-5 will that negate the modulated mic? |
Tech808
Moderator
Username: Tech808
Post Number: 2554
Registered: 8-2002
| | Posted on Wednesday, June 02, 2004 - 8:25 am: |
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Mobilepainter,
Adjusting VR-5 is you Modulation Limiter control so you can set your radio at 100 Percent modulation.
Personally I set mine at 90% and use a Power Mic also.
By cutting TR-29 this Defeats/Cancel's the Modulation control and leaves the radio wide open for well over 100% Modulation.
While I list Modification's when asked, I Personally have never seen any reason to Clip or Remove the Modulation Limiter's.
By Adjusting VR-5 it will give you all you need.
Adjusting VR-6 if Opened too far can cause distortion in your SSB Signal. This is where it is handy to have a scope or access to one.
I would start by adjusting VR-5 and testing it by talking with someone.
If you AM & SSB sounds good & clear and Not distorted to them leave it alone.
You Do want to have some swing in your Power, NOT just turn it all the way open.
Hope this help's.
Lon
Tech808
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Cm3885
Intermediate Member
Username: Cm3885
Post Number: 443
Registered: 12-2003
| | Posted on Thursday, June 03, 2004 - 2:28 pm: |
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Cutting the limiter will make your louder on that radio with just a stock mike. If you mod the radio you probably woint need a power mike because that 146 has a ton of audio when its done up right! Cut it and see what happens. If you dont like the results solder it back in... its that easy besides everyone cuts them anyways so i dont see what the deal is.
Anyhow, that 146 will have a TON of audio when its tuned up right! Good radio!!!!! |
Mobilepainter
New member
Username: Mobilepainter
Post Number: 4
Registered: 5-2004
| | Posted on Thursday, June 03, 2004 - 9:29 pm: |
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Ok, I may try that. Although I am not really sure about "tuned up right". I adjusted the "limiters" I believe they are called for AM and SSB power, about 14 watts is what it does on AM according to my radio shack SWR/power meter. I can hear you all chuckle right now.
I have a new problem however, I now am picking up "pops" each time a spark plug fires, it's not a whine but a small pop that changes with RPM. I have it in the same spot the TRC-520 was and it didnt make this noise. Would a filter fix this maybe or is it something else. I have the coax seperate from the power lines to my sterao amps in the back. I also use a Wilson 1000 mag mount antenna.
Any ides? sorry.... I have no knowledge of CB's other than what little I picked up years ago. I have installed every one of my own stereos and know the importance of good grounds and power/speaker wire managment to avoid the dreaded whine.
It's not horribly loud or anything, it just drives me crazy because it isn't perfect. |
Mobilepainter
New member
Username: Mobilepainter
Post Number: 5
Registered: 5-2004
| | Posted on Friday, June 04, 2004 - 10:25 pm: |
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Ok.... I looked for TR-29 but found that it had already been removed, completly. I have also read that a CB can never go over %100 modulation and that clipping or cutting this will produce unwanted harmonics. I really have no idea so I am throwing this out there for yall to wiegh in on.
I was to however able to contact a friend of mine who has a modified 148gtl via SSB at a distance of about 30 miles. While this may be childs play to most of you I was astounded at the clarity. I recieved my power mic today and am looking forward to trying again tonight to see if it helps at all.
One last thing. Will adjusting the pot for modulation, VR5, increase or decrease my mod with TR-29 being non-existant? |
Mobilepainter
New member
Username: Mobilepainter
Post Number: 6
Registered: 5-2004
| | Posted on Wednesday, June 09, 2004 - 7:19 pm: |
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I have a question concerning antennas. I have a mag mount wilson 1000, seems to work just fine. I have had it for over 10 years, I replaced the coax in it before I reinstalled it. My question is, on my Honda Civic what would be better. The wilson I currently use or a 5/8 wave firestick? |
Tech808
Moderator
Username: Tech808
Post Number: 2625
Registered: 8-2002
| | Posted on Wednesday, June 09, 2004 - 8:33 pm: |
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Personally, I would stick with the Mag Mount Wilson 1000.
I have alway's had excellent performance with them and they have been problem free.
Lon
Tech808 |
Cuddlebear
Intermediate Member
Username: Cuddlebear
Post Number: 197
Registered: 3-2002
| | Posted on Monday, June 28, 2004 - 6:32 am: |
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Mobilepainter Wrote:
"Ok.... I looked for TR-29 but found that it had already been removed, completly. I have also read that a CB can never go over %100 modulation and that clipping or cutting this will produce unwanted harmonics. I really have no idea so I am throwing this out there for yall to wiegh in on."
Dear MobilePainter,
It is my experience that a radio is way capable of producing more than 100% modulation with a clipped limiter. However, the extra modulation that is produced is a waste anyway due to the fact that the system can only handle so much. Think of it as a pool filled with water. If the pool is filled at 90% the walls or edge of the pool can keep the water in. If you overfill the pool, the water overflowes and has to go somewhere. Hence, you get unwanted harmonics, distortion, etc. Because you are flooding the system with so much, that it cannot process all of it. Therefore, You may sound loud, but distorted due to unwanted harmonics, bleedover, etc. The limiters job is to keep the audio at a rate that the system can handle and process to it's full ability. Therefore giving you a Un-distorted signal output, with as little harmonic overload as possible.
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