[Premium-Rx] WJ-8711, HF-1000, PIN DIODES QUESTION

[pat1mca at aol.com]

Greetings to List members,
After measuring the Ip3 of an 8711 receiver I have discovered a possible suspect PIN diode switch in the front end.
The diode in question is a type SMD FSDO1503 manufactured by National Semiconductors.
Up to now I have not discovered any info on this device whatsoever. Maybe well be discontinued  now ?

I would be extremely grateful if any member might suggest a modern equivalent or even a source of the original device.
Thankyou,
Pat G3YFK