The HP / Agilent 8753A, 8753B, 8753C, 8753D, 8753E, 8753ES and 8753ET vector network analyzers (VNA)

The HP/Agilent 8753 series are a range of vector network analyzers (VNAs) made by HP/Agilent that are very popular. Despite all of the 8753 series are discontinued and most are beyond support by Keysight, the 8753 is still an extremely popular VNA, mainly among commercial companies, but some are owned by radio amateurs or other hobbyists, as 8753 prices have fallen dramatically from their new cost. We don't know how many HP or Agilent 8753s were sold, but we find that around 30% of the customers of Kirkby Microwave SMA and N calibration kits are using 8753 series VNAs. All the HP 8753 series instruments can be used with the Kirkby Microwave coaxial calibration kits.

This page has a number of sections

  1. Hardware and software options.
  2. Add or enable software options 002, 006 and 010 on an HP or Agilent 8753.
  3. Differences between the various 8753 models
  4. Loading VNA calibration kit coefficients into the different 8753 models
  5. Calibrating the 8753

Hardware and software options for the HP / Agilent 8753 series VNAs

These instruments have a number of hardware and/or software options. Some options such as rack mount handles, extra manuals etc are not that important when buying a used instrument, as but others are. The main options are:

Add or enable software options 002, 006 and 010 on an HP or Agilent 8753.

If you have an 8753A, then it is only possible to add the time domain option (010). But on the 8753B, 8753C, 8753D, 8753E, 8753ES and 8753ET, it is possible to add options 002 (harmonic analysis), 006 (6 GHz) and 010 (time domain). Do not waste your time copying EEPROMs, as there's a much easier and safer way. Just email caesarv@email.com, with the serial number of your instrument, and what options you require. He will email you back some codes, which will unlock the options. You will need to search your service manual of your instrument to find out how to use the codes. On an 8753ES the procedure was:

  1. Open the HP 8753 VNA.
  2. Move a jumper on the CPU board that allows the EEPROM to be written to.
  3. Enter the service menu, pressing some buttons listed in the service manual.
  4. Set the title of the display to the same as the unlock code.
  5. Press some more buttons, which are again detailed in the service menue.
  6. Repeat steps 2-5 above for any other options required.
  7. Put back the jumper that allowed the EEPROM to be written to. This will preven accidental changes in future.
  8. Put the instrume back together.

Be aware that whilst option 006 (6 GHz) will work without any hardware changes on the 8753B and 8753C, this option requires a new source assembly and recalibration on an 8753D, 8753E, 8753ES or 8753ET. It is probably not economically viable to add option 006 to a 3 GHz 8753D, 8753E, 8753ES, or 8753ET.

Adding software option 002 (harmonic analysis) or 010 (time domain), do not require calibration on any 8753 series instrument.

Differences between the HP/Agilent 8753 series VNAs - only 50 Ω models are listed.

There are a large number of differences between the different models, although all can be used with our calibration kits. Some of the key differences are listed in the following table. If anyone finds any errors, or can add any comments, please contact us and we will correct it. The system dynamic range figures only relate to the A and B receiver inputs, not the R receiver input, which has a much lower dynamic range than the A and B inputs. Some instruments have slightly different specifications over some frequency ranges due to spurs or other odd reasons. Please check the manuals for full details.

Feature8753A8753B8753C8753D8753D (option 011)8753E8753E (option 011)8753ES8753ES (option 011)8753ET
A photo 8753C 8753D option 011 8753E 8753E option 011 option 011option 014 8753ES option 011 8753ET
DisplayMono CRTMono CRTColor CRTColor CRTColor CRTColor LCDColor LCDColor LCDColor LCDColor LCD
Lower frequency limit (without option 006)300 kHz 300 kHz300 kHz 300 kHz 300 kHz 30 kHz300 kHz 30 kHz300 kHz 300 kHz
Lower frequency limit (with option 006)N/A 300 kHz300 kHz 30 kHz 30 kHz 30 kHz300 kHz 30 kHz300 kHz 300 kHz
Upper frequency limit (without option 006)3 GHz 3 GHz3 GHz3 GHz3 GHz3 GHz 3 GHz 3 GHz3 GHz3 GHz
Upper frequency limit (with option 006)N/A6 GHz6 GHz6 GHz6 GHz6 GHz 6 GHz 6 GHz6 GHz6 GHz
Is option 006 just software?N/AYesYesNoNoNoNoNoNoNo
Integrated S-parameter test set No NoNoYes NoYesNoYes No No
Integrated T/R test set No No NoNo No No No No No Yes
Floppy disk drive NoNoNoYesYesYes Yes Yes Yes Yes
Time domain measurements (Option 010)YesYesYesYes Yes Yes Yes Yes Yes Yes
Harmonic measurements (Option 002)NoYesYesYes Yes Yes Yes Yes Yes Yes
Precision frequency reference (Option 1D5)NoNoNoYesYesYesYesYesYesYes
Maximum measurement points801160116011601160116011601160116011601
Frequency offset mode (for mixers) NoYesYesYesYesYesYesYesYesYes
System dynamic range (30 kHz-50 kHz)N/AN/A N/A 90 dB 100 dB? ?
System dynamic range (50 kHz-300 kHz)N/AN/A N/A 100 dB 100 dB ?
System dynamic range (300 kHz-16 MHz)100 dB 100 dB 100 dB 100 dB110 dB ? 100 dB
System dynamic range (16 MHz -1.3 GHz)100 dB 100 dB 100 dB 110 dB110 dB ?110 dB
System dynamic range (1.3 GHz-3 GHz)100 dB 100 dB 100 dB 110 dB110 dB? 110 dB
System dynamic range (3 GHz-6 GHz)N/A80 dB 95 dB 105 dB105 dB ? 105 dB
Real time clock NoNo No Yes Yes Yes Yes Yes Yes Yes
User defined preset NoNo No Yes Yes Yes Yes Yes Yes Yes
Latest firmware 1.013.004.136.14/7.14 7.747.74 7.747.74 7.74 7.74

Loading the calibration kit coefficients - necessary unless you are using the 8753's default APC7 kit

An 8753 when switched on will default to one of the internal calibration kits - probably the 85031 7mm (APC7) calibration kit. If you are not going to use that kit, then you must load the coefficients for the kit. Lots of people fail to do this, and get poor results because of it, although they don't often known this, as they don't check the results properly. The complexity of the process of loading the correct calibration kit coefficients depends on whether the kit is built into the firmware of the VNA or not. If built into the firmware it is very easy. If not built into the firmware, it is not hard to do, but is easier on the more recent models (8753D, 8753E, 8753ES and 8753ET) as these have floppy disks drives, whereas the old 8753A, 8753B and 8753C do not.

Loading the calibration kit coefficients for a kit in the firmware of the VNA

This is the easiest option, but a typical 8753 had about 6-12 kits in its firmware. HP, Agilent and Keysight have produced considerably more kits than this, so even using kits from HP, Agilent or Keysight, you will often find the kit is not in the firmware. We have in fact needed to load the coefficients for both the Agilent 85054B (type-N) and 85050B (APC7) kits we process, as neither are in the firmware of our 8753ES with the latest (7.74) firmware.

The coefficients for that inbuilt kit are loaded. You are ready to perform the calibration, as described below.

Loading the calibration kit coefficients from a floppy disk.

If, as it often the case, the coefficients for the kit you wish to use are not in the 8753, these must be loaded. The easiest way is if you have the coefficients on a floppy disk. The 8753D, 8753E, 8753ES and 8753ET have floppy disk drives, but not the 8753A, 8753B or 8753C.

At this point, assuming your floppy drive still works, you should get a list of the files on the floppy.

That will then load the coefficients into the USER kit. The USER kit will be the current kit, so you can then calibrate the instrument

Calibration

There are many forms of calibration an 8753 supports, but the most commonly used, and most accurate are:

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