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Author Topic: TA33Jr 15 meter SWR problem  (Read 271 times)
WB9YTG
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Posts: 6




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« on: September 13, 2019, 06:38:51 PM »

Restoring a TA33Jr of uncertain vintage. Poor SWR on 15 meters. 20 and 10 are ok

Trap problem? Ideas?

Thanks 73, Tom WB9YTG
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W9IQ
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Posts: 3534




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« Reply #1 on: September 13, 2019, 07:43:32 PM »

Tom,

It could very well be trap related. Each element has a unique trap and the trap must also be in the correct orientation (rubber cap end facing out).

Another common problem is that the weep holes become plugged and the trap fills up with water. The trap then often needs to be rebuilt due to corrosion.

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
WB9YTG
Member

Posts: 6




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« Reply #2 on: October 08, 2019, 04:53:30 AM »

Tom,

It could very well be trap related. Each element has a unique trap and the trap must also be in the correct orientation (rubber cap end facing out).

Another common problem is that the weep holes become plugged and the trap fills up with water. The trap then often needs to be rebuilt due to corrosion.

- Glenn W9IQ

Glenn, thank you.

Found that one of the coils was cracked (driven element). Tried rewinding, limited success. Interestingly, for reasons I can’t  fathom, antenna now resonates on 24 mhz(12 meters)! 

Mosley tech explained to me traps form a LC network, 10 and 15 coils are separate, the thin aluminum cover around those coils allows them to resonate on 20.

Ordered replacement driven element traps from Mosley.

73, Tom WB9YTG
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WB9YTG
Member

Posts: 6




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« Reply #3 on: October 11, 2019, 04:07:23 AM »

TA33Jr UPDATE!

Replacement traps seemed to have solved my SWR problem.

Interestingly, my repair/restoration effort may be partly to blame. One of the replacement stainless screws I was using may have been shorting one of the outer coils directly  to the element. A shorter screw seems to have made the difference. In any case, the 20+ year old TA33Jr is back on the air.

In retrospect, I should have purchased a new antenna! But what would I have learned?

73, Tom WB9YTG

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W9IQ
Member

Posts: 3534




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« Reply #4 on: October 11, 2019, 06:18:47 AM »

Great to hear, Tom. Enjoy the results of your efforts!

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
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