Astro 103


;     The Astro 103 is an Astro 102BX with the following updates:

I'm still looking for an Astro 103 with the optional CW filter.  So far, I have only the service and owner's manuals. The picture on this page was scanned from one of them.  Anyone out there looking to sell/trade their Astro 103?


 General Specifications

Frequency Coverage:

Frequency Control: Dual PTO (permeability tuned oscillator) with 6 digit frequency counter and RIT control.

PTO Modes of Operation:

Modes of Operation:  SSB with selectable sideband.  CW with automatic 800 Hz offset in transmit, with full or semi break-in.  CWN and RTTY modes with optional narrowband crystal filter.  (CWN is mode is CW with 400 Hz bandwidth crystal filter in receive.  RTTY is LSB with 400 Hz bandwidth crystal filter in receive.)

Power Input:  12-14 VDC negative ground only.  No damage will occur over the range of 10 to 15 VDC.  20 Amperes peak current required.

Electromagnetic Interference Reduction:

Dimensions: Power Connector: Antenna Connector:  UHF type, SO-239

External Speaker/Phones:  ¼" Phone jack; 4-8 ohms.

External Relay:  RCA jack, grounded when keyed.

Key:  RCA phono jack.

EXT Modulation:  RCA phono jack.

Fuse:  3 Ampere fast blow

External LO:  RCA phono jack

Auxiliary Antenna:  RCA phono jack.  Slide switch chooses auxiliary receive antenna or common antenna with transmit.


Circuit:  Single conversion to 9.00165 MHz IF using  double balanced mixer.  Exceptional immunity to overload and cross modulation.

Sensitivity:  0.35µV for 10dB S+N/N ratio.

Image Rejection:  Better than 60dB

Receiver Selectivity:

Passband Tuning: Dynamic Range:  AGC greater than 100dB; third order intercept +5dBm.  (IMD products down 90dB at –40dBm input)

Audio Output Power:  Greater than 3 watts into 4 ohms.

Meter:  S units from 1-9; 20, 40, 60 dB over S-9.


Circuit Design:  Conversion from 9.00165MHz IF.  ALC limits SSB peak output power and CW power to 100 watts.

Power Input:  235 watts PEP at 13.8 VDC supply.

Power Output:  100 watts PEP into 50 ohm non-reactive load at 13.8 VDC supply voltage.  ALC limits peak power to 100 watts PEP.

Unwanted Sideband Rejection:  60dB down at 1000 Hz audio frequency.

Harmonic Output:  45dB below peak power level

Carrier Suppression:  50dB below peak power level

Transmit Control:

Microphone Input:  47K ohms input impedance.

Audio Response:  300 - 3000 Hz, ±6dB

Meter:  Reads peak power on transmit selected by meter switch; forward power 100 watts full scale, reflected power 10 watts full scale, or ALC (Automatic Level Control).

Cooling:  Large capacity heat sink fins supplied.  For SSTV, RTTY, and semi continuous transmitting, forced air cooling supplied by a “muffin” type fan on heat sink fins is required.

VSWR Shutdown:

 Return to Cubic Mini-Museum
 Return to Radio Page
 Return to George's Place

Let's talk about Cubic Radios!