| Author |
Message |
    
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 132
Registered: 4-2006
| | Posted on Thursday, May 18, 2006 - 1:40 pm: | 
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Here is something weird I noticed yesterday after installing and tuning my predator. I have my SWR's as low as I can get them (1:3 with 18 feet of 9913 coax). Here is the weird part though. Let's say I key the mic (Mic gain all the way down), over the course of about 10 seconds while keying, I see the SWR meter rise slowly from 1:3 to about 1:8. This is with the amp at high power, as I lower the power of the amp, this effect propotionally goes away. Any thoughts? |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1630
Registered: 9-2004
| | Posted on Thursday, May 18, 2006 - 4:45 pm: |
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wwell, one thing is to try the same test with only the radio connected to the SWR meter, to make sure if its the amp or not.
im going to guess that something is happening when the pills get hot.
is the amp old?
maybe a bad cap?
i dont know.
matt |
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 135
Registered: 4-2006
| | Posted on Thursday, May 18, 2006 - 4:53 pm: |
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The amp is brand new. 667v. I was thinking that maybe over that 10 seconds the voltage is slowly dropping, hence, less wattage to the antenna. I know usually SWR's go up when the power goes up, but maybe in this case it is the opposite. Weird. |
Dale
Intermediate Member
Username: Dale
Post Number: 399
Registered: 12-2002
| | Posted on Thursday, May 18, 2006 - 5:49 pm: |
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well kid had same ideai had so i sy try find anoher meter or check grounds or add some |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1638
Registered: 9-2004
| | Posted on Thursday, May 18, 2006 - 9:49 pm: |
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ive looked at the pics of your setup james, and i cant see any obvious problems. looks great.
i loved the saw blade!!!
good metal, and a great stiffener. very cool!
anyway, all you can do is troubleshoot, try another meter, amp inline, amp out of line, etc..
good luck,
matt |
Rldrake
Intermediate Member
Username: Rldrake
Post Number: 138
Registered: 1-2006
| | Posted on Friday, May 19, 2006 - 12:33 am: |
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Are you using a loaded antenna or one with a matching capacitor? Sounds like your're heating it up. |
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 136
Registered: 4-2006
| | Posted on Friday, May 19, 2006 - 7:27 am: |
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a predator 10k. dual coil. 22" shaft |
Tech237
Moderator
Username: Tech237
Post Number: 351
Registered: 4-2004
| | Posted on Friday, May 19, 2006 - 12:57 pm: |
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James being a new amp doesnt prevent the possiblity of a bad part in it. The efect, as you describe it, is very remeniscient of a part getting hot and changing value as it gets hotter. THis could be anything from something in the radio, the amp or even the coax or bad solder joint. |
