(inspired by F6ETI - Noise (and not only) Meter 144 MHz - November 2020)
But centered on 1296 Mhz.
2 x LNA MMIC recovered in addition burnt and out of service. Must have been ERA-3 ?!
(Round boxes with almost illegible number 3)
Replacement and testing with some SMD Monolithic InGaP HBT MMIC Amplifier Gali-5 05 SOT89 that I had in stock.
And of course checks/measurements of the other components around!!
Specifications:
Gali-5-05
Gain 1 Ghz = 19 dB
Gain 1.3 Ghz = 18 dB
Gain 2 Ghz = 17.5 dB
Noise figure 3.5dB Roughly similar in performance to ERA-3
ERA-3
Gain 1 Ghz = 21dB
Gain 1.3 Ghz = 20 dB
Gain 2Ghz 18.7 Db
Noise figure = 3.5dB
Well, a little too much NF but I'm trying the drop! On the frequency that interests me, 1296 Mhz.
1st LNA, I see 2 attenuators of 6dB. The 1st has the input and the 2nd between the 2 MMICs. Without removing the attenuators, I place 2 Gali-5-05. Measurements by injecting a 1296 Mhz signal at 0dB with an HP 8648B.
Results: output = +24 dB 1nd LNA 1st attenuator of 6 dB has the input removed.
Installation of 2 Gali-5-05 on the 2nd LNA (2 attenuators removed) Measurements by injecting a 1296 Mhz signal at 0dB.
Result: output = +30 dB.
These 2 LNAs will be used for: an noise signal meter for the EME.
