| Author |
Message |
    
Biged
| | Posted on Tuesday, January 22, 2002 - 8:36 pm: | 
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I have a Uniden PC 78 with a Galaxy 400 footwarmer and a wilson 5000 antenna all hooked up in my car.My question is, is it normal for the swr's to go up when modulating?I have an swr warning light on my radio and it will flash once in a while when I am talking into the mic.So I hooked up my swr meter and checked them. With the amp off, I have 1.2:1 with the amp on I have the same.But when I modulate, the swr meter jumps like a power meter would.I checked all of my conections.It is a brand new system from stem to stern.even the jumpers.Thanks...Eddie |
409
| | Posted on Wednesday, January 23, 2002 - 3:50 am: |
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Yep.....Eddie, the SWR will go up when you key up and modulate the carrier just because of the power increase. The SWR meter measures the reflected power coming back from your antenna and when you crank up the power the meter sees more coming back. This is also why your warning light blinks. If your meter is downstream from the box,simply re-adjust the set control on the meter while keyed up and the reading will be closer to normal. |
Warlock
| | Posted on Wednesday, January 23, 2002 - 6:02 am: |
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Insufficient grounding can also cause this, as well as input swr (between the radio and amp). The first can sometimes be remedied by making sure the antenna is grounded well and/or the case of the amp has chassis ground. The second, check your swr between the radio and amp. Sometimes different jumper lengths show lower swr at the radio than others. |
Biged
| | Posted on Wednesday, January 23, 2002 - 5:43 pm: |
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Thank you very much 409 and warlock.Thats just what I needed to know.I am using a magnet mounted antenna so I am assuming that I am grounded right.Also, I am using a 3' jumper between the radio and the box, but I will try a dfferent length. |
409
| | Posted on Thursday, January 24, 2002 - 3:51 am: |
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Biged.....sometimes a longer jumper will work a little better when you have problems with your box.......GOOD LUCK !!!! |
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