There's little point in messing with the code. If you actually do a "hard reset" with switch, pulling PIC pin 4 to ground, it locks up every time.
My only objection to this PLL solution is the little noises it puts on the carrier every half-hour, when it goes through a re-tune cycle. However, if your loop filter capacitors are big enough (and of good enough quality), the noise is very low level....

Tbh I'm not really sure what the point is retuning every 30 mins. Surely once the pll is locked it should stay locked, and if it ever does go out of lock then waiting 30 mins to do anything about it isn't really helpful. Especially with no lock detect power down.

Maybe would be better to monitor the 1057 test pin to check for lock and only retune when its actually needed

TBH i dunno what all the fuss is about?

The PLL locks fine and stays locked! Yes it may "Glitch" 1% of the time?? But what digital gear doesnt have its flaws??

As for the 30 min refresh? You are talking micro seconds! Hardly recognisable by the human ear! Infact i prefer a system that can refresh its settings!

Just to clarify, I am going on my experience with my designs! I have not built the ZoZo version?

hello.can the T37-17 Ferrite toroid be replaced with a TN10/6/4
Ferrite toroid?Can it be effectively used at these frequencies?

No. It'd probably be too lossy.

There are suitable alternatives from Micrometals (any type 17 or type 10 that will fit), Amidon (any type 43 or type 61 that will fit) , and even Murata parts as well.

I used to make a small transformer like that using a small ferrite slug or a small ferrite tube - it doesn't have to be a ring core (toroid), but the toroid has minimal external radiations and tends to be most efficient.

Thanks for the reply.Can i use BF199 instead of MPSH10? (however different pinouts)
Can the oscilator and filter coils be replaced with air core ones?

You can replace the filter coils with air coils although it seems to tune up better with toko’s. If you change the oscillator to an air coil you might find it will become microphonic and pickup sounds around it.

I got my T37-17 toroid. can i use 0.5mm thickness enameled copper wire ? its the only one i can find now sourced from a 100uH inductor

Yes, that wire is adequate.

sinus trouble wrote: ↑Sun May 01, 2022 2:11 am Just to clarify, I am going on my experience with my designs! I have not built the ZoZo version?

I have built my own version of the zozo and it locks solid as a rock. Best pll iv used.

Zozo wrote: ↑Thu May 13, 2021 11:34 am Here's a quick look at the first MK3 board. I decided to stop using the BFLW-100 wire for the transformer stage, although it's a specially design wire for that purpose, I find it very difficult at times to split it apart. So as you can see in the photo, I've used just standard "twisted pair" ECW.

I don't know if anyone is the same as me when it comes to winding toroidals, but after making a few I also seem to have RSI in the palms of my hands.

The new exposed ground plane around the outer edge should make things a little easier for negative / braid connections.

The last change I made was to rotate the DC Choke inductor to the final stage, and increased the through-hole pitch.


20210513_110028.jpg

There's a couple of simple improvements that you can easily make to this board:

It's worth adding 47n or 100n capacitors to both of the regulators, between input and ground, and output and ground. You can tack either small ceramic leaded ones or surface-mount ones beneath the board, on the track side. These help to add to the regulator stability - especially in a strong RF field - and reduce both carrier noise and the already small spurious outputs. The capacitors need to be as close to the regulators as possible.

It's also worth adding small value chokes (or just a few turns through ferrite beads) into both the positive DC supply and the modulation input. Again, it improves performance and helps to ensure stability.

I have one of the Mk II boards here, with the output 4427 replaced with a 2SC730. It gives exactly 2.0 Watts on any frequency in Band II with a 13.25 Volt supply. With the small modifications outlined above, and a screen added to separate the output filter from the rest of the board, the performance is exceptional. Driving into a Mitsubishi RD70HVF1C power amplifier, it gives the magic 100 Watts with ease, though the FET is supposedly being hammered at that power! The output FET doesn't get particularly hot, and seems to be handling the power with ease. The only real drawback is that the supply current is pretty high (everything running at low voltage), necessitating thick power cables, but the big advantage is that it can be run from a leisure battery at that power level, so that it's possible to stay on-air even if the mains supply goes off.....

what is friend value for 40GPD?

RF-Head wrote: ↑Tue May 11, 2021 10:03 pm Found a picture of my old driverboard of 2001
Looks almost the same
If have not been on the same school as ZOZO