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Azur Electronics

The HP 5342A Microwave Frequency Counter provides frequency measurement up to 18GHz and cost $6,500 in 1987.

This Counter has options fitted: 001 oven controlled crystal oscillator $750 extra; 005 extension to 24GHz operation $500 extra; and 011 HP-IB control $550 extra. This increased the total cost of this counter to $8,300. Other options were also available: 002 Amplitude Measurement extra $1,600; 003 Extended Dynamic Range $650; 004 Digital to Analogue Converter $400; 006 Limiter Input Protection $500.

The serial number is much later than the downloaded HP Manual so several assemblies are different.

Front view with low and high frequency inputs
Signals in the frequency range of 10Hz up to 500MHz are measured by the direct count method. Signals in the frequency range of 500MHz to 24GHz are down-converted to an IF by a harmonic hetrodyne conversion technique.

Signals are normally measured using a fully Automatic mode. Alternatively signals can be measured in a Manual mode by entering the centre frequency within 50MHz. This is useful where there are several signals of different frequencies.

Frequency values to 1Hz resolution can be added to or subtracted from the measured frequency for IF Offset applications. All frequencies are displayed with up to 11 digits of selectable resolution from 1Hz to 1MHz on a red led display. The Counter has good FM and AM tolerance and automatic amplitude discrimination against other signals.

I use this as my 'reference' counter and also for high frequency measurements.

Rear view

Input 1 (High)
Frequency Range: 500MHz to 24GHz
Sensitivity: -22dBm 500MHz to 12.4GHz; -15dBm 12.4GHz to 24GHz
Impedance: 50Ω
Maximum Operating Level: +20dBm
Damage Level: +25dBm peak

Input 2 (Low)
Frequency Range: 10Hz to 520MHz
Sensitivity: 50Ω 25mV rms 10Hz to 520MHz; 1MΩ 50mV rms 10Hz to 25MHz
Maximum Input: 50Ω 3.5V rms +24dBm or 5Vdc fuse protected; 1MΩ 200Vdc +5V rms

Frequency Standard Output: 10MHz square wave 1.5Vpp into 50Ω
IF Output: 50MHz to 100MHz


Front Panel
Input 1 500MHz to 24GHz N-type Female
Input 2 10Hz to 520MHz BNC Female

Rear Panel
External Frequency Standard Input BNC Female
Frequency Standard Output BNC Female
IF Output BNC Female
Digital to Analogue Converter (not connected) BNC Female

May 2008

Some repair work was required to get this Counter fully operational, for details see Repair HP 5342A Microwave Frequency Counter. After this and a good clean up, the performance test was carried out.

June 2009

The 10MHz oven controlled oscillator from the HP 5342A is generally used as a source for the Azur SDU106 Signal Distribution Unit. This "locks" all the counters together to provide more accurate measurements.

October 2011

Acquired a second HP 5342A as part of a 'job lot' of equipment. This one has: option 001 oven controlled crystal oscillator; option 002 amplitude measurement; and 011 HP-IB control.

January 2015

Started testing this second 5342A but it had some faults and needed a good clean. For details see Repair HP 5342A Microwave Frequency Counter.

Option 002 adds: U2 High Frequency Amplitude Assembly fitted direct to the N-type connector; A27 Low Frequency Amplitude Assembly fitted to the front of the main chassis; extra wiring and coax cables to the Motherboard; and A16 PCB.

Frequency and Amplitude measurement
With Amplitude Measurement mode selected, the frequency is displayed on the left and the amplitude in dBm on the right. Resolution is 0.1dB and accuracy ±1.5dB. This is useful for a quick check of amplitude as well as frequency.

As I don't need 2 Counters, this 5342A has now been Sold, thanks Daniel.

November 2015

Acquired a third HP 5342A as part of a 'job lot' of equipment. This one has no options fitted.

December 2015

Started testing this third 5342A but it occasionally blows the mains fuse and doesn't count on the 500MHz to 18GHz range. For details see Repair HP 5342A Microwave Frequency Counter.

December 2016

Now repaired, decided to keep this 5342A.

August 2019

The third 5342A has now been sold (thanks Alan).