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Reading an old data tape--85052A cal kit?

Question asked by Wombat on Jan 2, 2008
Latest reply on Jan 2, 2008 by Wombat
Well, I needed a vector network analyzer, and I got a good deal on an old 8720A.  Then I got a really good deal on an 85052A cal kit for it.  Unfortunately, the 8720A prefers either and 85052B or 85052D cal kit.  But in the manual, there is an example of how to manually change the cal coefficients, create a user cal kit, and successfully use the 85052A cal kit.

So I did all that, using the generic cal kit coefficients in the 8720A manual.  I was able to get a cal to work.  But when I measured the short or open in the cal kit, I got an S11/S22 that arced over almost 360 degrees as the frequency moved from 130 MHz to 20 GHz. 

Then I dialed in around 34.5 pS electrical delay on both ports, and got the S11/S22 to colapse into a nice dot as the frequency was swept.

So, it looks like the cal was good, but I am guessing that the "offset delay" that I entered for the short and open was not the same in my cal kit as stated in the 8720A manual.

Now, the cal kit came with a data tape, labeled :7mm, 3.5 mm, type n calibration constants", and it seems that the cal kit was retested some recent time ago.  But I have no way of reading this data tape!  I suspect that the correct cal coefficients are on the tape, but there is no tape drive on the 8720A. 

So, any ideas on how to read an ancient HP tape?  I see on ebay that I can buy an old HP85.  Is there a stand alone data tape reader that HP sold, I might be able to find one used.  Any other ancient HP computers that might read this data tape. 

Thanks in advance!  

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