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Message |
    
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 12
Registered: 1-2004
| | Posted on Monday, March 01, 2004 - 8:56 pm: | 
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Hi folks,
Just finished hooking up my KL300-P in my car. After long hours of crimping, hooking up, and pulling wire, I tried it out. I've got squeal in it when I talk. It starts off OK and then starts to squeal as I talk. No squeal with the amp off.
Here's what I got and what I did.
I got a Radio Shack TRC-446 - all stock.
I've got a Radio Shack fiberglass whip on a magnet mount. (Could it be that the antenna can't take the power???)
I've got a stock mike that came with the radio.
I've got the amp hot and ground and the radio hot, ground and accessory going through the firewall and hooked straight to the battery + and -.
The amp hot and radio hot and accessory are butt-connected into a 10 gauge cable and hooked to the battery +.
The amp ground and the radio ground are butt connected into a 12 guage cable and hooked to the - battery post. I am also running another 12 guage cable from the - battery post to the frame. (Maybe this is not neccessary.)
Tha amp appears to be helping on the receive end cause if I turn the amp off, the squelch setting I was able to hear on before is too much. With the amp on, the squelch can go up and I can stil here traffic. I also have the RF gain on the radio about 1/2 way.
Some truckers on the interstate (a few miles away) are coming in loud and clear. But they say when I start talking a squeal develops and is not there when the amp is off.
SWR with the amp on or off is about 1 3/4 using the built in meter on the radio. I will be getting a Wilson 1000 mag mount this weekend, but until then I'm stuck with the radio shack fiberglass whip. (Can I harm the amp or the radio by using this antenna for a few days?? And could that be the cause of my probelms?
All ideas, comments and suggestions welcomed and encouraged :-)
Thanks.
Mark |
Tech808
Moderator
Username: Tech808
Post Number: 1658
Registered: 8-2002
| | Posted on Monday, March 01, 2004 - 11:08 pm: |
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Mark,
Do you have the Dead Key set to 2 to 2 1/2 Watts Drive?
You say the TRC-446 is Stock and that can mean you are over driving it.
I have and Use the KL300 and be Sure to Set the Drive (Dead Key) to 2 to 2 1/2 Watts and it will perfom very well.
Hope this help's.
Lon
Tech808 |
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 15
Registered: 1-2004
| | Posted on Monday, March 01, 2004 - 11:24 pm: |
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That, sir, is one thing I forgot to mention. I have not turned the watts down. It's still @ 4 watts or whatever it came stock as. I have the post #'s to use to turn it down, but am hesitant to do any internal turning of posts myself.
The amp specs say 1-7 watts input, if I recall. Is 4 watts enough to cause the squeal to develope on transmit? The trucker said it started out ok and the slight squeal started to build as I talked.
If I can't get it turned down for a week or so, am I in danger of ruining something?
Thanks Tech808, I think you may have hit the nail on the head.
Now if I can only get that darn engine noise out of it! :-) |
Mr_rf
Intermediate Member
Username: Mr_rf
Post Number: 267
Registered: 12-2001
| | Posted on Monday, March 01, 2004 - 11:41 pm: |
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Mark,
Sounds like the amp is going into oscillation due to installation errors...
Two things come to mind:
1. Try grounding the radio and amp to the vehicle chassis with as short a wire as possible for both (use a large diameter #10 ro #12...or the braided ground wire from RG8 or RG213 coax would be even better). Run two individual wires, one from the radio and one from the amp, to the chassis. Don't run just one wire from the radio to amp to chassis...this is called a ground loop and can possibly cause even more problems.
2. Mag mounts can cause really strange problems with power levels more than 25 to 50 watts. This is due to the lack of vehicle grounding at the base of the antenna. No ground at the antenna mount (better known as RF decoupling) allows the RF to travel back down the sheild of the coax and do weird stuff to the on-air signal. If possible try hooking a temporary ground between the mag mount itself and the vehicle chassis, or just get an L-bracket, trunk lip mount, or some type of permenant mount that provides a ground at the bottom of the antenna.
FYI...the position of th eAM/SSB switch won't cause problems on AM...just makes the amp delay a little before switching back to receive mode. just stick it in SSB and forget about it.
Good Luck |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1663
Registered: 12-2001
| | Posted on Tuesday, March 02, 2004 - 5:50 am: |
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You really need to increase the potential area below the magnet like a mega-mag from copper or ground the mag with a 8 gauge wire or put a ball mount on,it sounds like you are reaching the saturation point of the capacitive connection of the mag.and the amp is seeing a complete open in it's rf ground path,hence no bottom half of antenna or ground plane,definite squeal causer and amp fryer,poof!Bigbob |
Pig040
Intermediate Member
Username: Pig040
Post Number: 306
Registered: 7-2003
| | Posted on Tuesday, March 02, 2004 - 10:16 am: |
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Mark,
I agree with Mr Rf, s usual, it is important that the ground from the box be as short as possible, and to the vehicle frame. I had problems with my mobile installation until I did this. I used the seatbelt anchor bolt which on my truck goes right to the frame. At one time I ran 1500 watts through a Wilson 5000 magmount without a problem after changing the ground on the box. |
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 16
Registered: 1-2004
| | Posted on Tuesday, March 02, 2004 - 10:17 am: |
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Thanks for all the great information!
I will do a temp ground from the magnet down the rear window (where the coax runs) to the trunk lip and find a bolt there to connect to.
If I can get a good ground off of the magnet and get rid of the squeal, as far as wattage goes, am I taking a chance at frying the amp by using it before I get can get the radio turned down to 2 - 2 1/2 watts?
Am I taking a chance at frying the amp - poof - all things considered? Thanks for all your help.
Mark
CEF 288 |
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 17
Registered: 1-2004
| | Posted on Tuesday, March 02, 2004 - 10:36 am: |
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Would a Wilson 1000 mag mount handle the antenna grounding problem better than what I have? |
Chillydog
New member
Username: Chillydog
Post Number: 9
Registered: 12-2003
| | Posted on Tuesday, March 02, 2004 - 10:41 am: |
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Blackmountainme,
I know of no Radio Shack mag mount fibreglas CB antenna that will handle more than 20 or 25 watts RMS. The output power of the amp can damage the antenna. Following that, transmitting into a damaged antenna can take out your amp.
Regards,
Bob
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Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 18
Registered: 1-2004
| | Posted on Tuesday, March 02, 2004 - 12:34 pm: |
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Thanks for the input. I'm getting a triple mag mount and a 102" SS whip either tomorrow or thursday from work (Radio Shack :-)). Hope that will take care of my antenna probs.
Then I still have the problem of turning down the wattage from 4 to 2 - 2 1/2.
I tried it this morning with a co-worker, He went out and transmitted on my rig with it on low. It sounded great. No squeal. Then on high, no squeal, but it sounded way under powered and distant. Possibly becasue the motor wasn't running it wasn't getting enough juice? |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1665
Registered: 12-2001
| | Posted on Tuesday, March 02, 2004 - 9:02 pm: |
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OH,MAN,you gotta have that motor runnin' espesially with that amp,you need a regulated power supply an alternator is and a battery ain't.Ya know I've had a charmed life when it comes to radios,I've got a ten gauge wire that runs from the firewall of my '96 wt-1500 to the amp and the radio ground is spliced into it,I've got a stud style power tap under the hood at 30 amps that feeds the radio and amp,the amp sits under the seat and is turned on and off by a remote switch on the radio which controls a heavy-duty relay for amp,have 13'6" of mini-8 coax from amp to wilson silver load,on a Copper mega-magnet,never had a squeal ever,the amp has 2 sd1446 pills and is very linear,you can't tell it is on except it is LOUDER,my truck is full of flowers,chuckle.Bigbob |
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 20
Registered: 1-2004
| | Posted on Tuesday, March 02, 2004 - 9:35 pm: |
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My amp sits in the floor board right now and is turned on and off by my fingers ;-)>>
Yeah, I was pretty sure I needed good, live juice running to it.
I think I did a pretty good job of setting mine up since it was my first attempt at something like this. Also using 10 guage running from amp to + battery terminal and 12 guage grounds. The radio is connected and grounded seperately and is also connect at the battery. Got some good ground to the frame also.
Now I have to get a good ground on my antenna. Maybe when I get my tri-mag mount and 102 whip, I'll have a bit better luck with the antenna ground.
Then just gotta get the watts turned down to 2 - 2 1/2 and I'm off to the races :-)
Thanks for the reply.
Mark
CEF 288
Black Mountain, NC
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Pp1616
Junior Member
Username: Pp1616
Post Number: 24
Registered: 2-2004
| | Posted on Wednesday, March 03, 2004 - 10:19 am: |
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if i was u i would use the same gauge power and ground wire that can help out 2. as a car audio shop owner i install all kinds of stuff in cars. and like mr rf said the shorter the ground the better. also like thay said a badly grounded antenna is just asking for problems thats why i love my roof mount =)
cef#301 |
Blackmountainme
Junior Member
Username: Blackmountainme
Post Number: 21
Registered: 1-2004
| | Posted on Wednesday, March 03, 2004 - 9:55 pm: |
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I'm working on it folks and will keep you posted when I get the problems solved. Thanks for all the input! |
