Hi Corby et al, I've looked in service manuals for a few varied Rbs, and found only one that listed the SRD - it's like a secret! The one I found was SRS's PRS10 which used/uses Pulse Microwave's MP4025 but their input is 359MHz, rather than HP's 60MHz. It might work too but it's transition lifetime is Yes, when I swapped out parts I did retune. At one point I even had to also mess with the 5.315Mhz setting during the swapping as that test involved swapping out the Resonant Cell. If I were to guess, the poorer quality of the SMT could be due to the package size, either due its own characteristics at drive levels, or the fact that the SMT size messes with the microwave cavity's characteristics.
Based on some research, including HP's 1984_Transistor_and_Diode_Designers_Handbook, p290, the "best suited" HP part in the axial package that I could fine (if using HP's parts) with the largest transition time and can still generate the 6.8GHz would be the 5082-0825. But that does not match in any way the H391, 391, P391 markings on it. Neither does any of their other part#s. I suppose I could see if I can find some of those... Perhaps it was a specialty item? Considering the Super-ized quality we all kinda, would the quality of the SRD makes a difference, that is from batch/batch, mfr/mfr? (assuming it has the right functional characteristics, of course) Dan -Chickens are more obsessed with time than Humans. Proof: Clock Clock clock ________________________________ From: time-nuts <[email protected]> on behalf of [email protected] <[email protected]> Sent: Tuesday, August 28, 2018 1:09 PM To: [email protected] Subject: [time-nuts] HP5065A Step Recovery Diode, what part#? Hi, I'll throw my two bits in! Diodes from Efratom FRS, FRK, and M100 are made for 60Mhz drive and probably would be a good fit. I'll take a look and see if I have any junkers. All diodes used in Rubidiums are inside the cell oven so operate at a high temp anyway. I agree with Ed, swapping A3 modules requires retuning. One tidbit, make sure the two trim caps are actually rotating! The top rotor can get stuck and if you force it the screw connection will break. Then you have a fixed capacitor, not a variable anymore. If you check ahead of time you can break the rotor free by levering a tool against it laterally. Cheers, Corby _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
