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Crackle interference when other truck too close

J

jokerl90

Member
Sep 25, 2010
7
0
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I'm having a problem with my mobile cb for the past few days. When another truck is within about 100 yards or closer I get a lot of crackle through my ext speaker when they key up. It seems to get worse the closer they are and the longer they stay keyed up.
Once the other truck is beyond 100 or 200 yards away from me the crackle is gone and I can hear them clear as a bell.
Anyone have an idea what is causing this?
Cobra 29 classic, hustler HQ-27 antenna, all stock. On a 05 Mack Granite.
Thanks.
 

It sounds to me like the close proximity of the transmitting radio is overloading the receive of your radio. When you are that close to them turn your rf gain down.
 
jokerl90 said:
I'm having a problem with my mobile cb for the past few days. When another truck is within about 100 yards or closer I get a lot of crackle through my ext speaker when they key up. It seems to get worse the closer they are and the longer they stay keyed up.
Once the other truck is beyond 100 or 200 yards away from me the crackle is gone and I can hear them clear as a bell.
Anyone have an idea what is causing this?
Cobra 29 classic, hustler HQ-27 antenna, all stock. On a 05 Mack Granite.
Thanks.
Click to expand...

Is this one particular truck creating this condition or all trucks? Some trucks use power inverters and a lot of those create RFI.

Just a tip, those model of Mack trucks have a poor cab to chassis ground setup and I used to add ground strap from the cab to the frame at the pivot mount just under the door hinges (both sides) which cure many issues including that annoying static shock you get while exiting the vehicle.
 
If it's just one truck that's doing this, I'd suspect his radio has been clipped, snipped and otherwise mistreated. What this would cause is splatter and distortion that would likely be less noticeable the farther he is from you.

If ALL other trucks do this, I'd suspect your radio might be a little on the hot side as far as receiving, and I'd back the RF gain down a bit.
 
Thanks for the replies!
It's all trucks. The day before was happening with a couple of guys. Saturday morning there was 5 of us sitting at a redlight with tall buildings on both sides. a couple of then were talking and it sounded like everyone in the world was keyed up at the same time! That afternoon was running with one guy, tried different things, getting him to close in and back off made the difference.
I have heard of the ground issue with Macks, never seemed to have a problem with it though. Maybe the ground issue and the cold temps combined caused it.
 
Hey Beetle, I keep my squelch turned all the way down and use the RF Gain to control my reception. I was trying a bunch of different things to find the problem, can't remember for a fact if I turned the gain knob or not, but probably did..maybe..lol
 
jokerl90 said:
Hey Beetle, I keep my squelch turned all the way down and use the RF Gain to control my reception. I was trying a bunch of different things to find the problem, can't remember for a fact if I turned the gain knob or not, but probably did..maybe..lol
Click to expand...
id try the fr gain again. i also think your radio
is getting the frontend overloaded. if your really close may even have to turn rf gain
all way down.another test be careful doing this one unscew your antenna from
back of radio.DO NOT key your radio though.if you guys are in a truckstop
or parked somewere he,ll still come thru.cause your close.this will eliminate
any problems you may have with your antenna/coax setup.if he still sounds
that way id say its in his radio. or just too close.but unscewing your
antenna will tell you alot
 
yes, front end overload from a radio that is transmitting too close to your radio will cause the signal to distort, but something about the way you described your problem is making me wonder if you havent blown your external speaker.

obviously when a station gets closer, it gets louder, and maybe your speaker starts to break up at a certain volume level.

could be the cold temps you mentioned causing the speaker to break up, but im thinking that you need a new, or better quality external speaker.

try a different one and see if it doesnt clear up the problem.

LC
 
jokerl90 said:
I'm having a problem with my mobile cb for the past few days. When another truck is within about 100 yards or closer I get a lot of crackle through my ext speaker when they key up. It seems to get worse the closer they are and the longer they stay keyed up.
Once the other truck is beyond 100 or 200 yards away from me the crackle is gone and I can hear them clear as a bell.
Anyone have an idea what is causing this?
Cobra 29 classic, hustler HQ-27 antenna, all stock. On a 05 Mack Granite.
Thanks.
Click to expand...


Use the RF gain.
 
I agree might be the RF gain too high and his TX is overdriving the front end of your radio . Some speakers rattle as the other response said . Those rattle trap speakers drive me nuts . But, some of these high power radios that are made nOw do have some strong AUDIO !!!

On a separate note how is the HQ 27 antenna working out for you ?? Alot of dump buckets in my part of the country run those with great results . They really do make a BAREFOOT radio sound good from the ones I have heard .
 
The HQ 27 Is great for a dump truck. I have been told it's because the coil is above the cab and the bed. The downside of the HQ 27 is that it is easily broken under low tree branched and such. I did have one on a spring, but one cold cold morning it snapped after being bent over a little. I have 3 that are broken at the base of the antenna. I have been using a Wilson, but the stinger broke when it hit a low branch at highway speed. Took the HQ 27 off my pickup for time being..
My external speaker is this Cobra® HighGear HG-S500 Noise-Canceling CB Spkr. w/ Talkback
I haven't worked since the original post, so haven't been able to check on any of the ideas posted here.
 

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