[time-nuts] 58532A GPS antenna repair

[Matthias Jelen]

Hello Time-Nuts,

some time ago I ordered a box of Symmetricom 58532A GPS antennas for a bunch of Time-Nuts in Germany.
After a year or so one of the antennas installed on my fathers roof suddenly failed.

I opened it up and had a look inside. The circuit isn´t complicated: A low-noise FET stage (NE3508) followed by two bipolar amplifiers (2SC5508). Google found the components from the SMT markings, and it was obvious from the voltages that the FET had died. The FET is obsolete, and prices at the usual distributors are ridiculous, so I ordered 5 pieces on ebay from China (appx. 3$ including shipping...). After I replaced the FET the antenna worked fine again.

As I know that some of those antennas are around among the group members, I took some photos from the inside - maybe it´s helpful for someone running into a similiar problem.

I attached a PDF with the photos - I´m not sure if it will make it through the reflector. If not, drop me a pm if you are interested.

Regards,

Matthias
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