Hi,

I have a 8563A spectrum analiser that does not show any information. I found that the YIG oscilator soon after the input filter is in short to the ground. This is a 5086-7850 YIG from HP. Someone have any information about this filter? Where to by a good one (used or new)? Or information of how can I substitute this YIG for an more easy to buy model?

 

I checked Agilent's site and they only have an operators manual available. The YIG oscillators that I've worked on, require a bias current within a set range and will not oscillate outside this range. This current can go up to 500ma so you may think that the YIG coil is shorted when it really isn't. What is the resistance of the main coil?

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My YIG is the one the following picture:


The tuning have 66ohm and the heater have 33ohm, and both SMA (input and output), have 0ohm.

I already found others YIG but not this one.... the others have a lot of pins and connector.... I can't figure out how to substitute this one for another model...

Thanks for the Agilent manual, I did not found a explanation about the YIG coil yet, but have a lot of others usefull informations! Thanks!

 

The resistances seem normal to me. The 0Ω DC reading on the SMA's is probably fine. I'll bet they are 50Ω at the operating frequency. Measure the current on both coils when it is in circuit and operating. Some basic info on YIG oscillators can be found here. It should give you an idea about how a YTF, or YiG tune filter, works.

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Inside every little problem, is a big problem trying to get out.