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8748A test set with an 8753C

Question asked by EB5AGV on Jul 25, 2011
Latest reply on Jan 9, 2012 by EB5AGV
Hi all,

As some of you have probably read in another thread (http://jvgavila.com/hp8753c.htm), I am the new and proud owner of an 8753C

Now that it seems to work fine (thanks Dr Joel!), I am trying to setup a complete system. So I want to add a test set. But the real one (85046A) is completely out of my budget so I have thought on using, even if it will only reach 2.6GHz, my 8748A H26. You can see it along my 8754A at http://jvgavila.com/hp8754a.htm

I have been checking the Service Manual for both the 85046A and the 8748A. And they are very similar regarding to both the interface with the VNA and their construction. I have found the following differences:


  • 4 to 2600MHz (8748A) vs 300kHz to 3GHz (85046A)

  • Manual 70dB attenuator (8748A) vs Automatic 70dB attenuator (85046A)

  • Due to previous difference, more control lines on the 85046A interface

  • +20VDC power supply from VNA (8748A) vs +22VDC power supply from VNA (85046A)

  • Manual test direction control possible on 8748A

  • Local switch on 8748A

  • REF PLANE EXTENSION on 8748A

  • Very similar insertion loss and other RF parameters

I am probably missing something... but it seems to me that I could use the 8748A if I could instruct the 8753C to use a simpler test set, with some manual controls (test direction and attenuation, basically). I would only use the +22VDC power supply line from the VNA (perhaps with three Si power diodes in series to lower it to 20VDC) and would do all the switching manually.

Would this work?. Would I be able to calibrate the 8753C with this setup?. Any further hint?

Thanks and best regards,

JOSE  

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