[TenTec] Orion AM RX Performance Measurements

[Sinisa Hristov]

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Part One - Total Harmonic Distortion
====================================


Main RX, 3750 kHz, AM
PREAMP OFF, ATTN OFF, RF GAIN 100
ROOF 20 kHz, BW 6000 Hz, PBT 0 Hz
modulation freq = 300 Hz, modulation depth = 50 %
carrier level = -53 dBm (S9 + 20 dB)
measured at speaker output with external 4 Ohm speaker connected


          Total Harmonic Distortion
                 in Percent

HANG  dB/s    1.373b5   2.056
-----------------------------
0.3      5      0.41     0.44
0        5      1.27     0.65
0       50      4.8      3.1
0      100      8.0      5.8
0      200     13.4     10.5
0      500     24.5     21.4
0     1000     35       35

Orion can deliver up to 1.4 W into 4 Ohm load with
less than 0.5 % THD, using HANG of 0.3 seconds and 5 dB/s.

This is a static mesurement in laboratory conditions.
On the air performance seems to be affected a lot by selective fading.



Part Two - Frequency Response
=============================


Sub RX, V2.056, 900 kHz, AM 50 %, BW 6000 Hz.
measured at speaker output with external 4 Ohm speaker connected


Frequency Response in dB

         PBT setting
freq    0 Hz   1200 Hz
----------------------
 400    0.0     0.0
 500   -0.1    -0.1
 600   -0.2    -0.15
 700   -0.35   -0.3
 800   -0.5    -0.45
 900   -0.7    -0.55
1000   -0.9    -0.75
1100   -1.0    -0.9
1200   -1.2    -1.05
1300   -1.4    -1.2
1400   -1.5    -1.35
1500   -1.7    -1.45
1600   -1.8    -1.55
1700   -1.9    -2.1
1800   -2.0    -5.9
1900   -2.05   -7.7
2000   -2.1    -7.6
2100   -2.2    -7.7
2200   -2.25   -7.7
2300   -2.3    -7.7
2400   -2.3    -7.7
2500   -2.3    -7.7
2600   -2.35   -7.7
2700   -2.35   -7.8
2800   -2.35   -7.8
2900   -3.15   -7.8
3000  -12.6    -7.8
3100   none    -7.7
3200   none    -7.7
3300   none    -7.6
3400   none    -7.5
3500   none    -7.4
3600   none    -7.3
3700   none    -7.2
3800   none    -7.05
3900   none    -6.95
4000   none    -6.9
4100   none    -7.6
4200   none   -17.1


An attempt to shift PBT by 1200 Hz in order to obtain wider response,
results in response being DOWN by almost 6 dB from 1850 Hz up.
The weakened response continues up to 4.1 kHz.



Part Three - Equipment used
===========================

  HP 33120A Function Generator
  R&S SME 03 Signal Generator
  Amber 3501A Distortion & Noise Measurement System (True RMS)
  TDS 3054 Oscilloscope



73,

Sinisa  YT1NT, VE3EA