poor recieve

[p38]

i bought a cobra 25ltd at the tompson swap meet in ct for 20 and it had 18 ft of cable with it. i went out and purchased the power cord /antenna (102whip for $20)/and a radioshack swr meter I grounded mounted where my ball hitch goes with several washers and a carriage bolt i added a short ground strap later on . after re routing the cable from the drivers side to the passengers it dropped from way over 3 to 1.0 on channel one to 1.3 on 40. heres the thing when i move the mic my swr skoots up too 2.5 and to three sometimes.??? and i can hear people talking but they cannot hear me and im pretty sure its not skip! any ideas? i have it powerd through a cigarette lighter that i put together? kinda have a feeling this might have something to do with the poor receive .

[cbsupertech]

Hello Mr. p38!!!
The fact that you have a SWR problems indicates a bad RF ground...Corrosion on the shield connection at the antenna feedpoint, bad connection of the body section where the antenna is mounted to the rest of the vehicle (you might need to add ground straps....also poor coax cable shielding( bad piece of coax, dirty PL259 coax plug, connector on the back of the radio dirty or loose, even loose mic jack to chassis conection, or loose circuit board to radio frame screws...
prob is not DC ground or mic related...
at your service!
Mike ...CBSUPERTECH...

[p38]

thank my friend ill start at the connectors tomorrow , its too dam cold right now plus its dark lol.ill run through the whole system in the morning. its mounted on my 1998 blazer so have a quick disconnect on it so i can access the tailgate should i reclean this and put di electric grease on it?

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Friday, 07 December 2012, 21:30 PM

need some serious help on tuning this little gem. I turned up vr5 but im iffy on touching l10/l9/l8 because truthfully i have no clue of what they do.any guidance would be greatly appreciated . there arent any cb shops within my driving range as of yet so im stuck doing it myself.

[cbsupertech]

You can adj vr5 max &return it'll be loud but acceptable and adjustable w/ mic gain, unless your a purist lol...but Don't Clip Nothin!
As far as RF Jumping goes, use braid and remember a bright shiny connection is a good connection... Question looking dull connections can be real problem ...
Are remember a 64 Chevy fleetside pickup truck, When the match went bad he get out and jump in the bed, rusty frame connection!!!

[p38]

went through the whole system couldn't find anything my swr is higher on 40 than on 1?? and someone clipped d9 when you test the pep it swings to 15watts with it pushed together shes staying at 5. average power dead key is 2.5 and only swings to 3.5!! any suggestions?

[cbsupertech]

Troubleshoot by process of elimination...substitute another radio, if wave the mic around changes SWR
...problem is not radio...simple!
Restoring the clipped diode restores your amc control...if you want Super Swing® Modulation Controlled Carrier w/ Dial•A•Watt Control will serve you nicely( includes full High Performance Alignment) $45.00
Flat Rate CBRT FORUM Discount Price!
Otherwised I'm not suprised your radio doesn't swing right...a radio with reduced carrier can't swing w/amc functioning...overmodulation and distortion look good on the wattmeter, but sound terrible;)...
CBSUPERTECH

[p38]

yea i figured something was up! i looked it over once but i had that marines gut feeling again and sure enough something was amiss . il solder it together tm and when ive got the coing ill send it in for a tune up and some tweaking. ive built plenty of cars for my age (more than most) but when it comes to this level of computer tunning i dont have the necessary tools lol. I really appreciate the help ill run through it again tm and give it a better ground strap might move the antenna as well . heres a quick question looks like some one turned up vr2? where does it belong? its clearly labeled rx but i dont want to touch it without proper knowledge ha ha

[cbsupertech]

Hey P 38
I don't think of them as vr5the or vr2...already know what they do... I'm so familiar with the radio I can practically see the electricity flowing through it, and its functions just by looking at it, I just don't have that photgraphic memory I don't see the part numbers in the schematic in my head. .
dang it I'm at work I'm not able to look at the a layout...click: cbtricks/ radios/ cobra 25 ( on a Google search)...
That will give you the information you need
sorry brother
CBSUPERTECH

[jessejamesdallas]

Get a "NEW" radio that hasn't had any monkey hands in it...Golden Screwdrivers is a CB Radios worst enemy...

[p38]

Heg if your buying ill take a new one all kidding aside I will send it out too you or drop it off if my buddy is rolling through there .I'm done messing with it I changed the Mic and it helped big time Plus the jumper cable is stone age rat shack material from my grandfather(Arnold cook if anyone here knows him he's doing well after his quad bypass)picked up a noise filter and I'm going ti wire it to the battery . Mike what days are you open?or around .

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Monday, 10 December 2012, 1:23 AM

Jesse James I understand exactly what you mean! I pretty much bought someone else's head ache on this one.I'd low to find the guy and strangle his ... well you know what I mean but it gives me something to do in my spare time!I could do without the head aches though.I've already got one and she dont shut up!

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Monday, 10 December 2012, 15:25 PM

the noise filter is a xterminator 250 watt s-15 amps. are these any good?didnt cost me a dime but ive had some bad luck with noise filers for car steros before... it wasnt a pretty site

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Monday, 10 December 2012, 19:40 PM

well it wasn't the radio the mic was junk! picked up an astitic from a good friend .i went looking online and i came across a picture of the firestick k4a well i looked at mine and the insulated washer was on the wrong side of the mount . it came like that from the guy i bought it from so after a few minutes of calling it everything under the sun i swapped it around . perfect swr readings and a lot better reception from it. I guess the attention to detail thing hasn't sunk in yet . thanks for all the help guys

[cbsupertech]

WOW P38!!!
Talk about poor recieve! Yikes! A short circuited ANTENNA feedpoint ... now you know the car doesn't work to well as an antenna...
Great choice for a mic... you can't beat a D104!!!
I installed a "made in taiwan r.o.c." Cobra148gtl in my mobile to get the best recive with the least engine noise, tried pc66,pc78, trc451, (cobra equiv. 25ltd, 29ltd, 146gtl) the good ol' 148's noise blanker worked the best!!!
The noise filter kit you have usually has only a marginal effect if any...go ahead and try it though...
I ran coax direct from the battery to the radio, center as the positive, negative was the shield...added. 02,.001 bypass caps at the battery side of the coax( shielded power lead) an then used the filter unit with better results!
Good luck buddy...let me know if you need high performance mods done to your radio, just call me!
I have to recommend a big 102" whip also...ditch the 4ft. firestick!
Call me, lets talk!
At your service
Mike...CBSUPERTECH...

[p38]

i have a 102 whip ! with a quick disconnect. k4a stud assembly its coming in pretty good and transmitting okay defintley sending it out to ya when ive the $$$ . im painting the covers on it to match my k1500 truck. its a dark metallic blue . thanks for all the help man!ill call you soon

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Monday, 17 December 2012, 13:57 PM

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Monday, 17 December 2012, 13:57 PM

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Monday, 17 December 2012, 13:58 PM

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Monday, 17 December 2012, 14:44 PM

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Thursday, 31 January 2013, 21:27 PM

i took some time on my day off and made the plate metal too metal on the bumper cleaned my connections put some grease on it too protect from road salt (swamp yankee here ) bought a new 2ft cable for the swr meter because the old one gave up its ghost. my swr is a 2!? and 2.7 ish on 19? im thinking a spring added to the bottom may help this issue?