I have an new AL-1500 amplifier which doesn't perform very good on 14 and 21MHz.
Especially on 14MHz the efficiency is low.
I have already asked Ameritron to get their opinion, but they just say that
the plate should be minimum 3,2KV at full load and there should be 2KW out.
How I can obtain 3,2KV at full load without changing the transformer I don't
know!
Do anyone else have the same phenomenon with poor efficiency. Maybe Ameritron
have made a tradeoff in the tank-circuit between WARC-bands and traditional
bands which could compromise the performance.
Below I have listed all values I acheived in a test setup.
I would be greatful if anyone know what the problem is or could tell me if this
is "normal". My expectations went much further.....
73 de Soeren, OZ1FTU (OZ5W)
mailto:soeren_pedersen@chartec.dk
Measurement on Ameritron AL-1500
The amplifier is tested on a dummyload and output power (CW) is measured
with a Bird 43 and 1000H slug.
Plate voltage and current are measured with built-in meters in AL-1500.
Freq. Ua Ia Igrid Pout Drive Load Input Eff.
MHz Volt Amp. mA Watt Watt dial Watt %
1.83 3000 0.630 10 1000 32 2.6 1890 52.9
1.83 2900 0.900 115 1500 75 4 2610 57.5
3.65 3050 0.500 15 1000 30 3 1525 65.6
3.65 2850 0.925 65 1750 75 6.5 2636 66.4
7.05 3000 0.600 10 1000 1 1800 55.6
7.05 2850 0.950 65 1700 75 3.2 2708 62.8
10.13 2950 0.725 10 1000 0 2139 46.8
10.13 2800 0.975 65 1700 80 1 2730 62.3
14.20 2950 0.675 20 1000 4.8 1991 50.2
14.20 2750 1.040 75 1400 55 5.5 2860 49.0
14.20 2750 1+ 80 1700 75 6 3438 49.5
18.13 2950 0.675 15 1000 3.8 1991 50.2
18.13 2850 1.000 35 1250 65 5 2850 43.9
18.13 2800 1+ 60 1500 80 5 3360 44.6
21.22 3000 0.625 30 1000 5.6 1875 53.3
21.22 2850 1.000 50 1500 60 5 2850 52.6
24.90 3000 0.630 15 1000 6.4 1890 52.9
24.90 2850 1.000 90 1300 75 7 2850 45.6
28.50 3000 0.630 20 1000 7.4 1890 52.9
28.50 2850 1.000 75 1600 80 8 2850 56.1
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