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Author Topic: Ma5b mt1 blown  (Read 775 times)
EI5HL
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Posts: 2




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« on: December 07, 2012, 12:01:40 PM »

I have an MA5B beam. I have been using an ameritron amp rated 800watts pep. The trap mt1 outer coil burned out. I have replaced the coil with copper wire of a different gauge but am still getting a very high swr. Surely the only thing thats important is the length of the coil? I have checked the matcher on the aerial and it seems ok. Any ideas please?
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WX7G
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Posts: 5987




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« Reply #1 on: December 07, 2012, 12:34:56 PM »

The trap inductance must be correct. Changing the number of turns, the length, or the insulation material could be enough to detune the trap. A new trap might be the solution.

Fortunately the MA5B is rated for 600 watts CW and with the UK power limit being 400 watts should not be damaged. With the ALC adjusted correctly you will not again accidentally run 800 watts and damage a trap.
« Last Edit: December 07, 2012, 12:54:03 PM by WX7G » Logged
EI5HL
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Posts: 2




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« Reply #2 on: December 08, 2012, 11:29:07 AM »

Its tuning with a less high swr at the cw end of the band. Maybe if I take one or two turns on the copper coil it might tune?
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WX7G
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« Reply #3 on: December 08, 2012, 11:31:18 AM »

It's worth a try.
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