Co-phased firestik II antennas and am/fm antenna interference?

[ToolManTimTaylor]

Nope no boots. Hmmm I may just end up seperating the coax cables after all.

 

[Hammer]

Tool. .

The reason your sub is pounding when you use the CB is due to RF interference. There are two ways to fix it and stop the thump when you do not want it. 1 is to move the coax cable away from the stereo wiring completely and the other is to use a shielded wire for your stereo which will limit the RF interference.



Bodybomber. .

Now I do realize that its not my truck,but,if it was mine I would ditch the one antenna and run a single. Francis antennas are by no means el cheapo or junk they will work just as well as the next brand if properly tuned. With your setup and the swr you are telling us you need a longer whip. When the swr is higher on channel 1 than on channel 40 you need to lengthen the whip,when its lower one 1 and 40 is higher you need to shorten the whip.



When adding a ground you will want to use a stainless cable and mount it to the antenna mount and run it to the frame. You could ground the antenna to the bed and then run one to the frame from the bed if you maintain a area which will not corrode or compromise the ground. Do NOT ever run the antenna ground back to the area where you have the radio itself grounded as it will create more problems than you ever get figured out because of a loop being made.

 

[ToolManTimTaylor]

Ummm Andy, I use an Astatic RG-8X co-phase cable (The best I could find at the time and have heard from a few drivers that this cable rocks).



My system uses monster 302 xln RCA cables, which at the time were the bad azz cables that were shielded and super low loss. (Now they have super de duper ones LOL) and that is the only point of RF entry is the RCA cables correct? Can it be a ground plane thing?

 

[PRout]

TMTT, You can try some clamp-on ferrite beads from Radio shack. Thats one of the few items I'll buy from them, but they do work. They are made for stopping RF that is dancing down the surface of the wires and getting into your electronics. The amp could be picking up the RF on either the power leads, or the rca's, or speaker leads, or it could be at a place of lower signal level (like a preamp?) which is why some experimenting will be in order to find which wires are acting like antennas. Hopefully, the case of the amp & equipment is all metal and acting like a shield. If there is any open (non metal parts of the chassis' the RF could be entering that way).

I've had to use 5 or 6 of them (ferrites) on audio cables to keep RF out of audio gear before, and as hammer says, proper grounding of all radio & stereo equipment is critical. It all has to have its own connection direct to ground to avoid ground loops (which can act as unwanted receiving antennas), not be daisy chain grounded. The ground should be as wide and flat as possible because rf likes to travel on the surface of the conductor.

Don't know if that helps or not but just throwing it out here.

 

[PRout]

SoundStage! Synergizing - "Ferrite"-ing Out RFI (05/1998)

RadioShack.com

 

[Bodybomber]

I have the swr problem in check now. Put on some new Wilsons on and it helped a lot. The guy at the cb shop tuned them for me and got the swrs down to 1. 5 on 1-40. Now Im dealing with rf noise from my inverter and trans cooler fan. A ferite mag helped a lot on the inverter but not on the fan but I could only get one loop through on that one. I will put a longer wire on that so I can get multilpe loops on the mag and let you know what happens.