FCC Licensed Amateur Radio Operator, Extra Class

Motorola T-1504 Duplexer Repair and Refurbish

A set of Motorola T-1504A duplexer cavities arrived yesterday for repairs, overhaul, tuning, and testing. I managed to get them turned around in less than 24 hours. They will be on their way back to California

Motorola T-1504A Duplexer assembly, after refurbishing and repair, hooked up during final tuning and testing.


tomorrow. The owner of this set sent them to me because they would not tune. On opening and inspecting them, I found notable corrosion in a couple of the cavities, which I don’t think were original mates to the other two cavities (which were in considerably better shape internally when I started working on the set.)

Upon completion of the refurbishing and repairs, the set tuned up quite nicely with 116.38 dB of isolation and only 0.99 dB Insertion Loss in the low pass branch, and 108.91 dB of isolation and only 1.09 db of Insertion Loss in the high pass branch. That’s the kind of performance I like seeing from a set of duplexers when I finish working on them. This set should provide the owner with many more years of reliable service.


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