si5351 vhf pll

[00:06] <LA3PNA2> NT7S, when you find a break, would you mind sketchin out how you determined the PLL parameters for the Si? I kinda would like to use that if I do a beacon
[00:09] <NT7S> my algorithm?
[00:12] <LA3PNA2> more like, if we could figure out a program that determines the PLL freq and such when you input your wanted frequency
[00:13] <NT7S> ah
[00:14] <LA3PNA2> basicaly I'd like to be able to use that in the beacon
[00:14] <LA3PNA2> but, you should get on the JT9 first
[00:14] <NT7S> the general strategy is find a PLL frequency that is the highest integer divisor for the output frequency
[00:15] <NT7S> then tweak the PLL frequency the PPB to correct for the ref osc error
[00:15] <NT7S> so the divider for the PLL synth will not be an integer divider, but in many cases the multisynth will be
[00:16] <LA3PNA2> ah, so you aim for the multisynt to be a integer
[00:16] <NT7S> yes
[00:16] <LA3PNA2> that makes it a bit less muddy
[00:16] <NT7S> that's the goal
[00:17] <NT7S> but remind me, are you going to use the external PLL reference for this project?
[00:17] <LA3PNA2> maybe, I will make a test with the regular board, and no PLL first
[00:17] <NT7S> ok, I'm just curious why the regular library wouldn't work in this case
[00:18] <LA3PNA2> it would, its just that when using it on VHF, I do see some spurs, depending on frequency
[00:18] <LA3PNA2> and on LA1SHF we reduced it a great deal
[00:20] <NT7S> ah that
[00:20] <NT7S> now I remember
[00:20] <NT7S> hurr durr
[00:21] <NT7S> ok, you just need to pick your own PLL frequency that is an integer multiple of the output frequency, and set that manually, as per the example
[00:23] <NT7S> it will probably need to be a divider of 6 for a 2 meter frequency
[00:42] <LA3PNA2> hmm
[00:43] <LA3PNA2> idealy, one could write the program so that the frequency is set and the program selects the divider and pll freq
[00:43] <NT7S> right