XH Series of Monitor Receivers

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Description: The Canadian Marconi XH13, XH13A and XH-14 are a dual channel, transistorized superhetrodyne receivers for monitoring SSB or AM  transmissions
Frequency Range: 1.6 MHz to 24  MHz
DOT type Number CMC 6904
DOT Type approval  RSS 122

Intermediate Frequency 455 KHz

Frequency Stability
At ambient temperature of 0° to + 50°C better than 1 ppm
At ambient temperature of -30°C to + 60° C and +/- 10% supply voltage better than 2 ppm

Power Requirements
Receiver circuit only 9.6VDC:150 MA
Receiver with xtal ovens: 7W average
Receiver on AC- 30VA

RF Channels  1 or 2
(2nd channel available for opposite sideband or separate frequency up to l% from 1st channel)

Sensitivity
SSB:  0.5 uV for 12 db (S+N+D)/N
AM:    1.0 uV for 6 db (S+N+D)/N

Selectivity
SSB:    2.0 KHz at 6 db down and 6.0 Khz at 60 db down
AM:    6.0 Khz at 6 db down and 30.0 Khz at 60 db down

Spurious Response Rejection
IF (455 KHz) better than 90 db down
RF Below 10 MHz: all better than 60 db down
RF Above 10 MHz: all better than 50 db down

Radiation:
At Antenna Terminal  IF: less than 1.0 uV  all others less than 20 uV
To next Receiver  IF:  un-measurable,  all others less than 1.0 uV

Speech Clarifier Range
1.6 to 4.0 MHz + 0.002%
4 to 24.0 MHz + 0.005%

Operating Temperature Range -30°C to +60 C,   Warm -up period - less than 5 minutes

Type of Reception
6A3 - AM
A3H Compatible AM
A3J Suppressed carrier SSB

Metering Meter selection of signal level or AF Line Output

AF Output 11 dbm at 5% distortion to 600 ohm balanced line
I watt at 5% distortion via loudspeaker amplifier, accessory not available

AGC Range Output varies less than 12 db for signal variations between 5 uV and I volt
AGC Response 100 milliseconds
Hum and NoiseBetter than 40 db below rated output
Long Term Stability Better than 1 ppm per month
Remote Control  Provides operation of SSB/AM Mode Switch and Motordriven Speech Clarifier via the AF output line - one per receiver

Crystal Information
Beat Frequency Oscillator - 453.500 KHz
High Frequency Oscillator  Crystal is selected for desired channel of operation

AM or USB
Fx = Fc - 453.5 for AM or
Fx = Fc + 453.5 for LSB

where- Fx = Xtal Frequency, Fc = Carrier Frequency

All crystals may be ordered as per CMC Drawing 188-151. Specify LSB or USB and frequency.
Voice Operated Squelch
Input sensitivity  6 db (S+N+D)/(N+D) for an input of 10 mv
Dynamic range   will trigger for 7 db (S+N+D)/(N+D) worst case over a signal input range of 40 db

A coil kit is included but again first come first serve based on availability.(Ed- Copied from source. Don't know what that means)
1.6 - 2.25 MHz, @ 2
2.25 - 3.25 MHz @ 1
3.25 - 4.6 MHz not available
6.6 - 6.4 MHz @ 3
6.4 - 9.0 MHz not available

All marks include a Collins 455 KHz SSB mechanical filters   #F455-FA21-7444
 

XH-14 front view.Click on image to enlarge.

XH-14 top view. This receiver appears to be preset for 10 MHz. It can therefore copy signals from time signals station WWV.

XH-14 right side view

XH-14 bottom view

All XH-14 photos in this table via E-bay.

Frank Statham was a radio operator aboard ship. He provides some additional information on the XH series of monitor receivers.  "The XH14 was a horizontal mount, and the XH13 was a vertical mount.  Each type had a special shelf to expedite rack mounting.  The XH14 shelf held two receivers and the XG13 held four.  Most Canadian Coast Guard shore stations used the XH series as well as the weather ships.  The XH series provided SSB receive capability in the early days of transition from AM.

The receivers were trouble free and worked well, except for the fact that Marconi had trouble designing a decent squelch control circuit for them.   The squelch circuit used a couple of filters. An equal amount of low and high frequencies would mute the speaker.  A received voice would have more lower frequencies in it and cause the teeter totter to tilt and unmute the speaker.  As would a static burst etc.  Later on, Motorola came out with a syllabic squelch.  It detected not only voice frequencies but the pauses between words and sentences.  It was a much improved  SSB squelch, however. I can't remember if Marconi came out with a syllabic modification for the XH series".

Circled is a bank of ten XH14 monitor receivers. It is not known  why there are so many. The XH14s were connected to the 10 speakers on the left side of the equipment rack.  The photo was taken at Bull Harbour BC  (northern tip of Vancouver Island) in 1976.  (Photo provided by Frank Statham)

XH13 receiver. (Image via E-bay)

Type: Canadian Marconi Company  solid state, SSB and AM, fixed frequency, HF communications receiver.  Range: 1.6 MHz to 15 MHz Marconi # CMC 189-550. Instruction Manual $CMC 131-907 Circa: 1971 Comment: Click on thumbnail to enlarge the manual cover. Note that this receiver was made in a Canadian Marconi facility in Rahway N.J.  (Image via E-bay)

 
Contributors and Credits:

1)  Walter Isaacson VA7ANI  <wi1940(at)telus.net>
2) http://ve4lr.com/marconi-xh14.htm
3) https://www.usedvictoria.com/ReportSelectUsedAdPhoto2?used_ad_id=32779614&position=1&hb=14
4) Frank Statham <fstatham(at)gmail.com>

Jan 20/22