HP8554 mixer.

[F4UIU]

Hello. I hope you'll be able to understand my english.

I'd like to know what kind of diode to use to replace the two diode included
in the first mixer from an HP8554.

I have found this spectrum analyser plug-in and i have no local oscillator
trace on the zero frequency of the 141T display.
The first LO (YIG) is ok.

So, i think that the first mixer can be burned and two diode are included in
it. If i could find an equivalence reference.

If you know more things about 8554 than me..............................
Thanks in advance for your help.
-----------------------------------------------------------------------
Guillaume

 

[Dan Rae]

Bonjour Guillaume,
I have replaced the two diodes in mine with a single double hp microwave
mixer diode, if you follow me, the HSMS 2822. Because this is much
smaller than the original, and the diodes with the leads forms part of
the coupling circuit you will have to make wire leads that imitate the
shape and position of the originals. This is easier to do than to
describe! The wire leads to the SM component should be in the same
position as the original diodes and leads. Total cost abput 50
cents(US) and time about 10 minutes. Performance as good or better than
the original.

Just don't hit the mixer with more than about +10 dBm....

73
Dan ac6ao g3ncr


F4UIU wrote:

Hello. I hope you'll be able to understand my english.

I'd like to know what kind of diode to use to replace the two diode included
in the first mixer from an HP8554.

I have found this spectrum analyser plug-in and i have no local oscillator
trace on the zero frequency of the 141T display.
The first LO (YIG) is ok.

So, i think that the first mixer can be burned and two diode are included in
it. If i could find an equivalence reference.

If you know more things about 8554 than me..............................
Thanks in advance for your help.
-----------------------------------------------------------------------
Guillaume