| Author |
Message |
    
Galileo
| | Posted on Sunday, September 29, 2002 - 3:02 pm: | 
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Please help..I have a Comanche Warrior, and a KL300P..For power supplys, I have an Astron 35 amp, and a Pyramid 10 amp..Everything is fine when the radio, and amp are hooked up on the seperate power supplys, but when they are both hooked up on the Astron I have a terrible squeel on transmit, recieve is fine..I know it is not possible they are pulling to much current as they do not both add up to 35 amps..All station equiptment is common point grounded...Thanks for for any help on this..Tom Shaw |
Bigbob
| | Posted on Sunday, September 29, 2002 - 10:04 pm: |
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Try attaching a 47 micro-farad cap across the power leads close to the amp and put a .01 micro-farad disc cap across mike audio and sheild,both to by-pass RF.see if this works.Bigbob |
Jyd
| | Posted on Sunday, September 29, 2002 - 9:57 pm: |
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are they sitting to close to the power supply? |
Ss8541
| | Posted on Sunday, September 29, 2002 - 9:24 pm: |
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tom, the coax jumper between the amp and the radio also counts as a gnd point for rf. so you now have 2 gnds points here that make a perfect setting for a gnd loop(especially since the dc power gnds are at the same point for the amp and radio). try a different length of coax for your jumper. you can also put some ferrite beads over the coax and power cord to break up the gnd loop. |
Galileo
| | Posted on Monday, September 30, 2002 - 7:29 pm: |
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Jyd,
the ppwer supplys are under my desk, and the radio and amp are on top...Thanks, for all the replys..Tom Shaw |
Bigbob
| | Posted on Monday, September 30, 2002 - 8:10 pm: |
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Ss8541,that's exactly the same hook up I have in my truck,only the power supply is the alt.and the battrey is to far away to act as a filter,but both units are sheilded by the body.I've got the caps as mentioned above.I had a supply that both the primary and secondary were grounded at a common point to the line ground(the green wire),had a 50watt boot on it and it sqeeled like crazy,found the prob.clipped it,no more squeal,I probably should have reconected it with an inductor.You see the house wireing was feeding rf back through the grounds and causing the problem. |
Bigbob
| | Posted on Monday, October 07, 2002 - 7:47 pm: |
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Look at the filtering used in a base supply then copy it in your mobile supply,problem solved.Oh yeah put two 200 micro-henry inductors in the radio grnd. and pos. supply leads. |
2600
| | Posted on Wednesday, October 09, 2002 - 1:39 am: |
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Of all the "filtering" methods you can try to prevent RF from the amp leaking into the radio, using two power supplies DOES work, at least.
Maybe tying up a second power supply for the radio alone is the cheapest way to accomplish it. Just depends on how much you figure the aggravation of making them run on a single supply is worth to you.
73 |
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