VK3XDK Agile/versitile PLL V2!!!

[VK3XDK]

Gday everyone,
the "versatile" PLL board has had a make-over (V2)

It now offers much better flexibility and performance due to it now having the si4133GT chip as standard (programmable R divider)
The board is also smaller and has facilities for MMIC amplification on both outputs.
There is facilities for an on-board (in/ext. switchable) reference oscillator. It will be an optional extra (good 10Mhz oscillators are too expensive to add as standard, and it's probably not needed by most)
there are a few other changes please see documentation (PDF attachment)

I am now getting most components factory installed and should be able to supply the board for less that the original (less labor for me), prices are still to be decided.

[VK2OMD]

Well done Graham.

The programmable R divider doesn't just open up more frequencies for more convenient IF selection, but it may allow high PD frequency for some than the fixed R divider allowed... and that should improve PN for those cases.

Owen

[VK4GHZ]

The programmable R divider doesn't just open up more frequencies for more convenient IF selection, but it may allow high PD frequency for some than the fixed R divider allowed... and that should improve PN for those cases

That's exactly what I did to my original XDK PLLs, whose Ref Dividers were fixed at 65.

10 MHz reference / 65 = 153.84615 kHz.
Multiple that by 13 (the intended Ref frequency was 13.000 MHz), and we magically arrive at 2 MHz steps - the "even MHz" limitation of the original Agile PLL.

With a retrofitted a "GT" variant, any desired dot zero MHz LO output can now utilise a PD of 1 MHz, the Si4133's upper limit.
PN plots can be found on interwebs that demonstrate the reduced PN with a higher PD f.

Of course, it goes the other way as well. The minimum PD spec is only 10 kHz!

Good work Graham.

[VK4ALH]

Hi Graham,
I'm interested in getting one of these boards. Could you please let me know when you have worked out the price?
73
Leicester Hibbert
VK4ALH

[VK3XDK]

Thanks for the positive comments,

Yes using a dividable R really moves the system up a few notches

I have experimented with PD's of 200, 250, 500KHz and 1Mhz =As the PD goes up phase noise goes down. (to a limit)

I have (at the moment) settled for a PD of 250KHz, which is a compromise between phase noise and visible PD spurs.
Results are showing (A/B tests) that i am getting around 4-6db lower phase noise (10khz) than the original board. Unfortunately i haven't got good enough equipment to provide actual figures (i'll leave that to the experts )

I could have gone for a cheaper (ie 14.4Mhz) on-board oscillator but decided on 10MHz for better versatility when it comes to reference divisions. (and PD experimentation)

AS for the prices,
Without on-board oscillator AUS$75
With on-board oscillator AUS$95
Postage is around $7(padded box) within VK

Please email for orders (grumss@yahoo.com.au)

[VK3XDK]

AND another thing,
some may have noticed that the MMICs (when installed) have on-board mosfet buffers (driven from the processor)
switching the MMICs off (software) decreases the outputs by around 30-32db and makes for a VERY easy beacon. (on-off for keying)

Some "advanced features/usage" documentation is planned for the future.

[VK2JDS]

Hi All, I have one of these boards and need to change the frequencies.
Does anyone have the pic code handy they could share. It doesnt appear anywhere on the web.
73 Dave vk2jds
Vk2jds@hotmail.com

[VK2XAX]

Hi All, I have one of these boards and need to change the frequencies.
Does anyone have the pic code handy they could share. It doesnt appear anywhere on the web.
73 Dave vk2jds
Vk2jds@hotmail.com

I do, I'll send it to you.

[VK2JDS]

Tim sent the older pcb V1 code, so i am still on the lookout for the V2 pcb code if anyone has it,
Thanks

[VK2JDS]

Further progress.
I found some 14M code on Adam vk4ghz site that runs the si4133D chip, which is the same as on the V2 vk2xdk pll.
Tried version 4 and 5.
After editing the line picaxe 14M , changing it to picaxe 14M2 it still wont work.
run out of ideas to make this go....
the pll runs fine with the original 14M2 chip in it, and the second chip i am reprogramming is out of a V1 xdk, which is good, as i am reinstalling the V1 code back in it after trying to make it go in the V2 pcb with the si4133D (gt) chip on it.
73 Dave vk2jds

[VK4GHZ]

Further progress.
I found some 14M code on Adam vk4ghz site that runs the si4133D chip, which is the same as on the V2 vk2xdk pll.
Tried version 4 and 5.
After editing the line picaxe 14M , changing it to picaxe 14M2 it still wont work.
run out of ideas to make this go....

Dave, the M and M2 have subtle coding differences. Port definition is one of them. Refer to the relevant PDF that is available.

Cruising Ha Long bay at the moment, so it's a bit awkward for me to do that for you. It's an easy edit. Or you could use the other MCU type.

Sent from my SM-G970F using Tapatalk

[VK2JDS]

Hi Adam, thanks for the reply, and re the subtle coding changes its a bit above me... i can change frequencies but not much further than that.
When you get time then i will be interested to get some prods in the right direction. I had hoped someone had a working template i could just edit for the 76 GHz LO freq i needed to load into this vk3xdk V2 pcb.
enjoy Ha Long bay
73 Dave vk2jds