[VHFcontesting] How to GPS lock FT-817?

Gregory Winters greg_winters at hotmail.com
Fri Nov 8 22:07:07 EST 2019


I'm interested in locking my FT-817 non-ND to a GPS external reference for driving my transverters. The transverters have that external reference ability, so all I would need is to lock the IF rig. Stock 817 performance is around 4ppm. The high stability TCXO-9 is about 0.5ppm. But GPS locking it can get potentially better phase noise and 0.5ppb if done right... supposedly.

I'd like to run EME someday, so ppb accuracy would be great.

I've seen outdated info on different sites about using a no longer available VK3HZ board, different Kuhne PLLs, etc. But nothing that explains the various steps with a PCB or orher things that are available anymore. At least not that I could find.

>From what I've already seen, it looks like a board of some sort containing an input from a GPS reference is connected to the internals. The critical part seems to be having a PLL circuit either modified or built to utilize the new reference. It seems somewhat simple except for the PLL part, which is rarely explained.

Has anyone successfully done this? How did you do it? Was it expensive?

de Greg, K3RW

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