[Test-Equipment] HP8901A modulation analyzer

[Ron Youvan]

   Robert W9RAN Nickels wrote:

> Wonder if any fellow hams are using the 8901A to measure/monitor higher
> powered transmitters, and what techniques are recommended for reducing
> the power level.  The 8901A is spec'ed for 1 W (+30 dBm) input with
> overload protection to 35 watts, so 20 to 30 dBm of attenuation would be
> needed for typical amateur power levels.  A fixed attenuator should work
> fine for bench work but since the 8901A has automatic level adjustment,
> I wonder if a simple coupling loop would be sufficient for in-line
> monitoring (provided the level is<  1 watt).  Obviously power level
> measurement wouldn't be accurate without a calibrated attenuator.
> Thanks for any ideas, it looks like a nice piece of gear.

   The standard broadcasting way is to feed it from a directional coupler with 30 or 40 dB of 
isolation and a lower power attenuator (2 watts) to bring the sample into the sweet spot of the test 
instrument's input range.  If the load is lost the sample will not harm the instrument, as only 
incident power will be sampled.
   The hp-8901A looks like a sweet thing to own.
-- 
    73 Ron KA4INM - All E-mail sent to this address shall linger in the Google cloud forever!