CBers are killing me.

Jim Florence · Post by **Jim Florence** » 27 Aug 2000 6:38 am

When I use my old Fender, occasionaly the CB radios will burst in without warning and at incredible volume. I'm sure they all have linear amplifiers as FCC rules are not enforced here. Question is how can I guard against this? Even with my volume turned down the noise is incredibly loud.

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Jack Stoner · Post by **Jack Stoner** » 27 Aug 2000 10:20 am

Make sure all your cables and connectors are grounded good. Poor grade shielded cables or unshielded connectors will contributed to the problem (cables with plastic molded connectors instead of the better grade with the metal barrel) A lot of it comes in via the reverb. You may want to turn the reverb off and see if that helps.

This is just a start, but something you can do or check on easily.

Blake Hawkins · Post by **Blake Hawkins** » 27 Aug 2000 10:44 am

Do what Jack says first.
If that does not help you might want to try placing small bypass caps across the instrument input and across the input and output of the reverb tank. You need caps small enough to not affect the tone of the instrument but large enough to short out the CB signals. Something in the range of 10 to 250 picofarad would be a starting point. You might have to experiment to find the right value.
If the signal is coming through the guitar pickup, then the bypass should on the guitar.
Otherwise...the input of the amp, close to the input transistor.
You need to determine exactly where the signal ingress is happening. Since it is very loud, it is probably getting into the input stage or the guitar.
You may be able to confirm that by turning down the volume, first with the pedal, then with the control on the amp.
If a simple cap does not work, then more shielding or a more elaborate tuned circuit would be the next step.
If you have a matchbox...try that.
Blake

Blake Hawkins · Post by **Blake Hawkins** » 27 Aug 2000 10:50 am

OOps...reread your post.
If the signal is still there with the volume control on the amp turned down, then the ingress is after the control...probably in a driver stage. (Also see if it is still there with the reverb all the way off.)
I once worked on a television studio audio system which did that...only it was a nearby AM broadcast station...cured it with a tuned circuit connected from the base to the emitter of the transistor.
Blake

Rich Paton · Post by **Rich Paton** » 27 Aug 2000 11:40 am

Rent a Caterpiller D-8 at your local equipment rental yard, and offer to mow the offender's radio room for free. Insist on this thougtful gesture...if you did it while he is away for the day, the effect of surprise would no doubt enhance his appreciation of the work.<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Rich Paton on 27 August 2000 at 12:42 PM.]</p></FONT>

Steve Feldman · Post by **Steve Feldman** » 27 Aug 2000 12:55 pm

If you all can get that figured out, maybe you can help me get rid of those damn diesels driving past my house. I know most folks have a problem with land mines.....

Hamilton Barnard · Post by **Hamilton Barnard** » 29 Aug 2000 7:16 am

If you all can get that figured out, maybe you could help me get rid of those black helicopters that are always flying over my house. They seem to mostly come around whenever I'm test firing one of my machine guns.

Jim, since the FCC is doing nothing (oh wow, surprise...), it might be time to get out the ol' staple gun. If you know where that guys lives, shoot a staple (or small nail) right into his coax. It'll take him forever find it. And hopefully by the time that he has, he will have blown the final out of his linear.

Ric Epperle · Post by **Ric Epperle** » 29 Aug 2000 9:55 am

The term for this phenomena is "Audio Rectification".. Very common, especially in older gear.(amps, etc.)

gary darr · Post by **gary darr** » 1 Sep 2000 1:36 pm

If you know where the antenna is, just a quick snap will do. just don't get caught! Just kiddin Ha Ha

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