Peter Miles
Northam, Western Australia QRZ Page: VK6YSF
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70cm MAST HEAD PRE-AMPLIFIER REPAIR
Mini-kits EME221-70CM 70cm Mast Head Pre-amplifier. 23 July 2024
Repairs completed on
the mini-kits EME221-70CM mast head pre-amplifier involved the replacement of the
surface mounted PGA-103 and PSA-0012 MMIC Amplifier chips. It
was determined during the repair work that the PGA-103 chip was not
faulty, however it was replaced as it was not worth undoing the work.
IC1,
PGA-103 High Dynamic range MMIC Amplifier 0.05-4GHz
Low
Noise Figure, 0.6 at 1 GHz; 0.9 dB at 2 GHz
Gain,
11.0 dB typ. at 2 GHz
IC2,
PSA-0012 High Dynamic Range MMIC Amplifier 0.05-6GHz
Low
Noise Figure, 2.4 dB typ. at 1 GHz
Gain,
16 dB typ. at 1 GHz
Figure
1. Circuit schematic EME221-70CM mast head pre-amplifier
Photo
1. Completed EME221-70CM mast head pre-amplifier board.
Video
of repairs including on air test carried out with the International
Space Station repeater in a contact with VK6GC.
See construction of
the EME221-70CM mast head pre-amplifier kit:
