I'm the proud owner of one of these beasts. I think it was probably military surplus at one time. Agilent makes some mention of the option reducing upprer frequency to 18 GHz with improved VSWR spec, but I haven't found anything more specific than the VSWR specs.
My theory and hope is that this is basically a standard 11793A, and the frequency limitation is all in the 11792A (which I don't have). I have run it up to about 21 GHz and it seems to work fine there, but I start running into IF power limitations above that because I don't have a generator strong enough to give good IF power at those frequencies.
I cracked open the 11793A and the part numbers seem to match what would be in any standard 11793A except the mixer itself which isn't marked. If anyone can offer any insight into this option, it would be much appreciated.
I thought I had a PDF file on that one; but I can't find it. I did, however, find the following at the Agilent website:
*************************
STANDARD SPECIFICATIONS
SWR for a standard Agilent 11793A is specified only when it is part of an 8902S system and when using an 11792A sensor module in Tuned RF Level mode.
Input SWR
< 1.15 < 1300 MHz
< 1.32 < 1300 MHz to 18 GHz
< 1.43 < 18 GHz to 26.5 GHz
H04 SPECIFICATIONS
In the E04 system, the Agilent 11793A and 11792A are equipped with option H04 which provides better than standard SWR specs for the frequency range of 10 MHz to 18 GHz in Tuned RF Level mode. Notice the difference in frequency coverage between the standard and H04 specifications.
Input SWR
< 1.25 10 MHz to 12.4 GHz
< 1.30 12.4 GHz to 18 GHz
***************************
If I comprehend correctly, it seems H04 works over the full range, but has better/improved SWR specs to 18 GHz.
Thanks Hawaii. That's exactly what I had seen before. The thing that makes me think the system only works to 18 GHz is the last sentence of what you pasted which says- "Notice the difference in frequency coverage between the standard and H04 specifications."
Pretty sketchy info from Agilent. I HATE H options.