Hi all,

Just as a followup : We have repaired our 51013 Boonton diode probe using a
double MA4E501 diode from Siemens/MA-COM.

Procedure : probe dismounted, old diodes desoldered (warning : on the N
connector side there is a disk capacitor nearly invisible between the
diodes' ends and the connector). Common pin of the MA4E501 cut at the
shortest and directly soldered on the disk capacitor fitted on the N
connector pin, both other pins directly soldered on the 160 ohm serial
resistors installed in the original probe serially with the diodes.

Results are not as perfect as the original specifically paired and selected
diodes from Boonton (understand : repaired probe doesn't work at 18GHz),
however the probe is reasonnably good up to 5GHz : Measured return loss is
under 25dB up to 3GHz, under 20dB up to 4GHz, but is above 8dB at 8GHz. We
don't have a directionnal coupler between 4 and 8GHz in hands so I don't
know the exact limit but it seems to be around 5-6GHz. Sensitivity is
around -40dBm, in line with the original.

Of course the probe now needs to be recalibrated, but it is back to life !
For those who are interested we have written a small summary of the repair,
with a couple of pictures. It is in french but I guess that pictures will be
understandable worldwide ;+). The network analysis plots show the
measurement on a reference high end 51081 probe (left) and the repaired
51013 probe (right). See www.alciom.com/fr/download/reparation51013.pdf

Now if anyone have a calibration procedure for the boonton probe I would be
interested... The user manual of the milliwattmeter explain how to enter
calibration factors for a probe, but no how to measure them...

Friendly yorus,
Robert Lacoste
www.alciom.com



"Robert Lacoste" use-contact-at-www-alciom-com-for-email a écrit dans le
message de news: ...
"K7ITM" a écrit dans le message de news:
...
On Nov 9, 8:17 am, "Robert Lacoste" use-contact-at-www-alciom-com-for-
email wrote:
Hi,

I have a faulty Boonton 51013 power sensor, which is a diode based probe
for
the 4220 RF milliwattmeters. And one of the two detection diodes is out.
Of
course both diodes would probably need to be replaced and full
calibration
to be done again; but do you have any idea for a potential replacement
diode, not too difficult to find and working up to 10 or 20GHz ?

Thanks for your ideas. Experiences of 510XX sensors repairs would be
also
welcome, as the diodes are packed in a copper film...

Robert

Don't know specifically about your Boonton, but would a diode from the
Avago HSCH-53xx series be useful? Some are rated for use up to
26GHz. They are small, of course, about .006 inches wide and .027
inches long (with leads that could perhaps be cut to yield perhaps .
020 inch net length, if absolutely necessary).

Cheers,
Tom

Thanks Tom.