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Author Topic: Tram 1481 bad caps now I have questions  (Read 1151 times)
KD7WPQ
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Posts: 36




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« on: December 21, 2012, 10:37:33 PM »

OK, so recently I started receiving reports from fellow operators that my signal just didn't sound good. One day I was great, the next ok then following I couldn't key a repeater that normally I don't have a problem with so I took my antenna down, took it apart and everything seems fine but the caps smell like stinky electronics. Not like they caught fire but they stink and I'm not exactly sure how to test caps. I know how to test resistors but not caps.
Mind you prior to taking it down I tested the reflection and was getting about 8watts reflected out of 15 from 144 to 145 and from 147 to 148 but only 1 watt reflected on 146. So my antenna is extremely narrow.
So currently I have replacement caps on order but I am wondering how much would it change the values in the antenna if I replaced the caps with 2kv caps instead of the 1kv caps it came with to try and avoid this from happening again.

Currently I only run up to 50W and my antenna is connected using LMR600 with pigtail adapters between the radio and coax and also between the coax and antenna to allow for the PL259 connectors at the antenna and radio.

Anyhow, I'm not exactly sure how the caps popped since the antenna is rated for 200W and I can only max out at 50W but I'm pretty sure the caps are bad.

As a side note I did notice that the tip of the wire inside the fiberglass tube at the top looked as if it had gotten really hot at some point because it is blackish on the last 4 to 6 inches.
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N8CMQ
Member

Posts: 353




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« Reply #1 on: December 22, 2012, 05:03:11 PM »

One word, lightning.
You might want to measure the continuity of the wire.
If it is open, you will need to replace the vertical
element.
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KD7WPQ
Member

Posts: 36




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« Reply #2 on: December 22, 2012, 06:35:09 PM »

but had it been hit by lightning wouldn't that also damage my radio? Radio shows no signs of damage and I don't disconnect my antenna and radio very often and thus far this year not at all.
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KB4QAA
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Posts: 2323




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« Reply #3 on: December 24, 2012, 01:47:25 PM »

-"A fish rots from the head"  Chinese saying

-"A radio rots from the electrolytic caps"  Ham saying

Smelly caps, and a burnt antenna are called "CLUES".  Don't try and rationalize why they can't possibly be bad.  They are.  Something bad happened. Maybe more than one bad thing.

Replace the caps. Test if you want to, but don't avoid replacing them or put power on the radio until they are replaced and you have gone through the entire radio visually,and with that good sniffer of yours.  Smiley    

Best pull the  antenna and coax and do visual and VOM checks too.

At least you discovered the problem before something caught fire or burned up; maybe while you were out of the house.    73, bill

[edit]  p.s.  Read the eham reviews on, the TRAM 1481 n.b. water leaks, soaked spacers and blown capacitor.  Much to check out on your antenna.   http://www.eham.net/reviews/detail/4203
« Last Edit: December 24, 2012, 01:54:51 PM by KB4QAA » Logged
WX7G
Member

Posts: 5947




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« Reply #4 on: December 25, 2012, 10:25:07 AM »

The low VSWR at 146 MHz tells us the caps are not damaged. I think the VSWR problem is caused by the pigtail adapters.
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