22-01-2022, 05:13 PM
Yet more work on the Chinese 2m amp.
replaced the four 100pF output caps with four 30pF caps for a better match. ( 2 per side )
Rewound the LPF coils using 2.4mm wire to replace the 1.3mm wire coils that got quite hot on extended key down tests.
power out = 57.3dBm - 537w
Power drawn = 14.9A@50v for an efficiency of 72%
Also did harmonic tests, 2nd harmonic is -58dBm. Others not visible on the SA! see pic.
Last mod to do is to up-rate the 12ohm coax - waiting on the postal service for that.
cheers
Tim
replaced the four 100pF output caps with four 30pF caps for a better match. ( 2 per side )
Rewound the LPF coils using 2.4mm wire to replace the 1.3mm wire coils that got quite hot on extended key down tests.
power out = 57.3dBm - 537w
Power drawn = 14.9A@50v for an efficiency of 72%
Also did harmonic tests, 2nd harmonic is -58dBm. Others not visible on the SA! see pic.
Last mod to do is to up-rate the 12ohm coax - waiting on the postal service for that.
cheers
Tim