Hallicrafters SX-28A Receiver

Hallicrafters SX-28A
Performance Test

Hallicrafters SX-28A


Band	MDS	Blocking	Two-tone D.R.
		(20 kHz)	(20 kHz)

80 meters	-140 dBm	102 dB	60 dB
40 meters	-139 dBm	103 dB	57 dB
20 meters	-139 dBm	108 dB	58 dB

AM Audio S/N: 52 dB

AM Audio Frequency Response:

100 Hz

200 Hz

400 Hz

600 Hz

800 Hz

1 kHz

2 kHz

3 kHz

4 kHz

5 kHz

6 kHz

+2 dB

+1 dB

0 dB

-2 dB

AM Audio Distortion:



Mod%	100 Hz	200 Hz	400 Hz	600 Hz	800 Hz	1 kHz	2 kHz

30%	4.0%	2.0%	1.6%	1.4%	1.4%	1.4%	1.4%
50%	5.6%	2.5%	1.4%	1.3%	1.2%	1.2%	1.3%
70%	10%	2.8%	2.2%	2.2%	2.0%	2.0%	2.5%
90%	18%	18%	16%	14%	14%	14%	14%
100%	22%	20%	18%	18%	16%	16%	16%

Notes: Maximum i-f bandwidth measured about 14 kHz @ -6 dB on this receiver. Before running the audio frequency response and audio distortion test the tone control was adjusted for flat response with the bass switch "in".

AM distortion numbers show the somewhat typical increase at lower audio frequencies - most often caused by the low audio frequencies riding on the AGC line. Also there is the usual increase in audio distortion as the modulation percentage increases. This is due to the detector's inability to cleanly demodulate the higher amplitude levels.