Dear sirs,

I have a E8285A service monitor, and I know I can put no DC voltage on its inputs. So I have 3 questions:

- Can I keep a DC blocker permanently connected to its inputs?
- Is there a quality difference on a HP DC blocker and a chinese one?
- Why it doesnt come standard from factory?

Thanks!
Alexandre, PU2SEX - GG66QM

Alexandre, a DC block functions as a series capacitor in your input signal path. This keeps DC out, but being a capacitor, also has a response at RF that resembles a high pass filter. The cutoff frequency depends on the capacitor value in the DC block. Measurements of RF signals will be affected near and below this cutoff frequency. You should look at the frequency response curve for the DC block to make sure it will not interfere with signals you intend to measure. You could look at the spec sheet or sweep the DC block with your E8285A like you would sweep a filter to confirm its response.
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73, Steve W9TN

To take it one step further, you could make your own as long as you verify its operation in the frequency range you desire.
I like the idea of cheap protection Instead of expensive and labor intensive repairs.
I like the idea of a 3 to 10db attenuator that you can take apart and add SMD cap and fuse.?
Especially useful for stage gain checks.? IFR used to have a retrofit bnc connector with a small fuse.

jb or anyone,

Have you ever seen a commercial attenuator that you could take apart (in the proper way without sawing or grinding)?

So far I haven't.

Hank
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Some of the BNCs will unscrew and you might have to replace the insides, so if you smoke one dont throw it away.

Last time i repurposed one was a 75 ohm BNC type.? I rebuilt as a 50 ohm 60 db for close-in T- hunting.

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