New Antenna = Problem

[jdgee]

Hello,
A co-worker makes/sells/mounts/sets up a mobile antenna. It's rated excellent by numerous users, compared to Wilson and claimed to be much better. It's a coiled (enclosed in plastic tube) design antenna. Other drivers are using low cost radios and expensive radios with this antenna, w/no problems.

Having one installed, I hooked up my 3 year old SuperStar3900

I experienced no problem until the truck's engine was started. Once started, I get very STRONG alternator noise (whine ). It's in the "receive" and "transmit" modes. People can hear my voice, but also complain of loud background "whine" .

Having the factory antenna in place (8 inch. from new antenna), I tried it. Same problem occurs ?!!? I've used the factory antenna and SuperStar in this truck for 500,000 miles. Never had a problem with it.

Using the same microphone and power cord, I hooked up my Cobra 25. No problems, works GREAT !!

W/the SuperStar, I can disconnect the power cord's "ground" wire, and the radio still works. This is a NEW issue. It also happens now, with the original antenna setup, and ONLY with the SuperStar. Viewed by some, as an "excellent ground", I think it relates to my problem. Again... never happened prior to new antenna. With the Cobra, when the ground wire is removed, the radio shuts off, just like the S.Star once did.

I tried different power supply sources/circuits on the truck.
I tried the "new / never used before", SuperStar microphone.
I took the SuperStar to a radio techn., NO problems were detected.
I hooked up the SuperStar in a different truck. No problems .
I ran a seperate ground wire from the power source , to the SuperStar's chassis.

Clearly, The SuperStar does not like the new antenna.
This new antenna, must also be effecting the original factory antenna..... "talk about strange " !!??
Is it possible the SuperStar's circuit design is the problem ?
Anyone familiar with this radio ?
What else could I look for, or change ?

Only thing I have not done yet, is to hook up the SuperStar in another truck, which has this NEW type antenna installed.

Any ideas / thoughts / opinions are welcome ...
Thanks, jdgee

 

[jdgee]

Hello,
Thanks for the "views". I know this is an odd problem, made worse by my messy details. Simply put...

... I've got a new antenna.
A SuperStar radio doesn't like it
A Cobra likes it
Same power cord & Mic used for both radios
Both radios check out as "ok", when put on the "bench".

Hope this helps... ?
Jdgee

 

[Fdtrucker]

try this

sounds like you have a noize problem with the superstar it must be more sensative to noize than the cobra. this has nothing to do with the antenna. I would try a noize filter. you can get them at most cb shops.

 

[jdgee]

Fdtrucker,

Thanks for the reply. I mentioned to the builder of my new antenna, that a noise filter might be a good thing to try. I'll check it out. The antenna guy is as baffled as I am. We've got a dozen or so drivers using the very same antenna, using different radios. I've got the only SuperStar in the bunch, and have been the 1st person to experience a problem.

Are Torriod cores / ferrett rings something that radio guys ever use? They are common in my radio controlled helicopter hobby, but I've never heard them mentioned from the CB world. They help with "RF" interference. I'm not sure if (as example ) alternator noise falls in that catagory or not. Anyway, thanks again !
Later, jdgee

 

[freecell]

"W/the SuperStar, I can disconnect the power cord's "ground" wire, and the radio still works. This is a NEW issue. It also happens now, with the original antenna setup, and ONLY with the SuperStar."

your superstar is getting its dc ground connection via the feedline shield-to-ground at the antenna mounting bracket. disconnect the dc ground wire AND the antenna connector from the rear of the radio and it will power down. re-connect EITHER one of them and it will power back up.

 

[Moleculo]

Ground loop has got to be part of the problem. Question is what do you do about it?

 

[jdgee]

Hello, and thanks to all, for the help

Ground Loop ? Interesting... I mentioned that to the guy (fellow driver) who makes up these new antennas. Also mentioned it to the "radio tech." who checked out my SuperStar and said it's 100% AOK ! That radio man has a very good reputation. Anyway...

My explaination / definition of "ground loop" is lame. I understand a small amount of "what it is", but only to the extent, that I put it into the " anomaly " catagory . I view it as " if it goes away, don't ask " WHY ?? " That's the limit of my high tech understanding.

Last night, I hooked up my S.Star in a different truck. Same make and model truck , different antenna. It's an el'cheap , similiar to what I was using prior to my homemade antenna (details above, starting this thread)

Basicly, the radio worked fine. I called for a radio check and got an impressive reply. It's always been a good talker. No alternator noise (whine) in the receiver or transmit . One thing that does continue to be a new problem, is this "ground loop" theroy.

I disconnected the power supply's ground wire. The radio still did not power off, but also did not seem to be fully powered up. The lights on the radio were very dim, and the radio wasn't working. In my truck, w/the new antenna, the radio was fully powered up, with or without the p.supply ground (netural) wire connected.

I still believe something is wrong in the radio. This is how it all started... When connecting my SuperStar to this new antenna the first time, the "male pin" on the coax plug was very tight . I needed more than normal pressure to insert the coax, and gave some slight rotating motion , while pushing in on the plug (connector). That is when this all happened.

I mentioned this "tight plug", to the radio tech. He didn't seem to concerned. Note: he bench tested the radio. It wasn't done, while in the truck. Can the radio's coax plug (rear of radio) get damaged somehow, to allow an odd ground loop type condition to happen ?? Using a screwdriver, I can rotate the female segment (insert or part), of the radio's coax connector. I've looked inside the radio. The bare wire that runs from the coax connector, to the "board" looks to be correct. I only rotate the inner section of that plug a few degrees... maybe 5° back and forth.

The radio's coax connector in the S.Star is different than the one used in my Cobra. The S.Star uses, what I guess to be a better plug. The segment where the coax "pin" enters, is totally enclosed. From the inside of the radio, you can't see the connector's pin. On my Cobra, you can see the pin. I know... "So What " ?!!?? I'm desperate and radio challenged.. ok ?

I think I'm going to use wire and make a test. Using the 2 wires, I'll bypass the radio's antenna connecton plug. Than I'll remove the power supply's ground wire, to see if the radio stays on, or goes off , like it did before. Process of elimination is really my only diagnostic tool(s). But... it works! Sometimes...

Monday night (4/4/05 ), I was getting ready to start my run (work), and the guy who makes these antenna's came up to my truck. He feels bad, that I'm having problems. We both feel like the antenna is not the problem. Still, it's just how he is. Anyway, he gave me a new Magnum S3 to play with. I don't have a problem with that radio. It works fine in the truck.

Pretty darn nice radio too !! The recieve is excellent on the S3, but nosier than my SuperStar. That's the best thing about my poor sick S.Star. It always had a quiet "receive" nature to it. The S3 is very similar to my Cobra25... a bit noisy. Never though I was into " lights ", but the S3's blue lighting is very cool , and the "turbo echo" is a lot of fun ! Much different than my S.Star, which has the Connex echo board installed.

Well anyway.. my old Cobra25, and this Magnum S3 like the new antenna. Both radios will "power off" , as soon as I disconnect the power supply's ground (netural) wire. And no alternator noise either.

Sorry for the novel !! Jdgee