thanks PSYCHO .always good work love youre work ,and always the simple great ideas .This is simple great it must be with a clean sound.the only problem is the tuned oscillator.

Just increase the pad size and would be fine.

XXL wrote:Just increase the pad size and would be fine.

Xxl your right there. I would just increase the pads would make sense to what he's doing.

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Hello Necks!

I am proud to present a revisit to the Sinus 1 Watt PLL! Featuring upgrades such as PCB layout, Dual Varicap for improved audio response and tuning capabilities and a Lock state indicator!

Although i am still in the testing phase? Stability seems to be greatly improved, Also the audio sounds punchy and natural.

The actual RF power out has yet to be accurately measured and possible adjustments made? But overall it has blown away my sceptical expectations!

Images and schematic to follow!

Just to add, The purple trimmer so far seems to be pretty much redundant which could be replaced by a green trimmer (22p) or a fixed capacitor.

Nice work Sinus and thank you for sharing your hard work. I was wondering if there's going to be Gerber files for people to just order there on PCB's? Talking of such, what's the dimensions of the PCB. This is purely a guess just by looking at the components and spacing, But I reckon about 100mm X 70mm ?

I think it looks a bit longer than 100mm if the yellow trimmers are anything to scale it by. I'd say it looks about 130mm long

Sinus
If you carefully examine the design of the NRG PLL Pro III, you'll see how the final two stages were configured to be broadband - you could do away with your yellow trimmers completely. Stephen and I experimented with a driver stage that used a pair of BF199s in a sort of push-push configuration, driving into a 2N4427 for 1 Watt at 12V supply. It was a no-tune configuration, and gave very close to 1 Watt throughout the band. This was (possibly) going to be the PLL Pro IIIa - with the PLL Pro III remaining as the 4 Watt / 1 Watt switchable version.

I also experimented with the little Soshin filters, in a paired set-up, so that the PA stages would incorporate both high-pass (to get rid of the ½f product on the way in, and low-pass to get rid of the higher harmonics (particularly 1½f) after the 4427. The low-pass filter I was using was capable of handling a little more than a Watt, so was ideal for the no-tune 1 Watt version.....

There are several companies that make suitable filters, and will make you a batch of them with the specification you require quite cheaply. I found a supplier (for example) of 60MHz bandpass filters that I used for link transmitters and receivers.

sinus very good progress , add an out of lock power down to it

but still not wideband oscillator

Zozo wrote: ↑Sun Mar 21, 2021 10:38 am Nice work Sinus and thank you for sharing your hard work. I was wondering if there's going to be Gerber files for people to just order there on PCB's? Talking of such, what's the dimensions of the PCB. This is purely a guess just by looking at the components and spacing, But I reckon about 100mm X 70mm ?

Thank you Zozo

I will share the Gerber files very soon, Just out of curiosity what method did you use to share your files?

To answer yours and tecknics question, It is certainly not the most compact exciter!

The actual dimensions are 149mm x 78mm

sinus trouble wrote: ↑Sun Mar 21, 2021 11:27 pm

Zozo wrote: ↑Sun Mar 21, 2021 10:38 am Nice work Sinus and thank you for sharing your hard work. I was wondering if there's going to be Gerber files for people to just order there on PCB's? Talking of such, what's the dimensions of the PCB. This is purely a guess just by looking at the components and spacing, But I reckon about 100mm X 70mm ?

Thank you Zozo

I will share the Gerber files very soon, Just out of curiosity what method did you use to share your files?

To answer yours and tecknics question, It is certainly not the most compact exciter!

The actual dimensions are 149mm x 78mm

All good on the dimensions, I wasn't to far of in the Z Axis

Ok the method I use for sharing on this forum is simply using the attachments option in "Full Edit" mode. Just Zip up your Gerber's as normal and it will be fine. The .Zip file extension is a supported format on here for attachments.

Albert H wrote: ↑Sun Mar 21, 2021 4:57 pm Sinus
If you carefully examine the design of the NRG PLL Pro III, you'll see how the final two stages were configured to be broadband - you could do away with your yellow trimmers completely. Stephen and I experimented with a driver stage that used a pair of BF199s in a sort of push-push configuration, driving into a 2N4427 for 1 Watt at 12V supply. It was a no-tune configuration, and gave very close to 1 Watt throughout the band. This was (possibly) going to be the PLL Pro IIIa - with the PLL Pro III remaining as the 4 Watt / 1 Watt switchable version.

As you may have guessed? I am a big fan of yours and Stephens work so to mess with the design too much would be Blasphemy!

However, I often thought that L7 (4 Turn coil) could be replaced as a transformer primary coupled to a secondary to drive the 2N4427?

radium98 wrote: ↑Sun Mar 21, 2021 5:31 pm sinus very good progress , add an out of lock power down to it

but still not wideband oscillator

Thank you Radium

I may add OLPD at some point? So far it is super stable and only 1 Watt so not a priority.

Zozo wrote: ↑Sun Mar 21, 2021 11:45 pm
All good on the dimensions, I wasn't to far of in the Z Axis

Ok the method I use for sharing on this forum is simply using the attachments option in "Full Edit" mode. Just Zip up your Gerber's as normal and it will be fine. The .Zip file extension is a supported format on here for attachments.

Yeh its not huge! And very easy to repair if anything went wrong? So far a Massive improvement on my previous hand etched efforts.

I had trouble with file share in the past especially with the RDS software as it contained EXE files, Your advice is much appreciated!

radium98 wrote: ↑Sun Mar 21, 2021 5:31 pm sinus very good progress , add an out of lock power down to it

but still not wideband oscillator

You really don't want a wideband oscillator - the phase noise comes up rapidly, and the increased bias sensitivity can make it more prone to hum problems. My modification to Stephen's oscillator used capacitors switched in (from the PLL frequency setting switches) through diodes, adding more and more capacitance as you went down the band. It was configured so that the varicaps would give the VCO about 4 MHz swing, so there were four capacitors switched in in various combinations to give full band coverage. It worked very well, but the board layout was somewhat tricky!

The other option for the VCO was to provide a 30V tuning voltage - a voltage multiplier can be used to give 30V for the PLL control voltage - the SAA1057 handles 30V for Vcc3 - and this goes a long way to making the VCO no-tune

As I suggested above, a wideband driver and PA stage would be a good idea (to eliminate the expensive trimmers), and OLPD is a sensible precaution. If the modulation varicap can be biased correctly by the loop control voltage (you'll need an op-amp to get the necessary voltage response), you can get consistent mod sensitivity right across the band. This then means that an on-board deviation limiter is quite easy to implement.

sinus trouble wrote: ↑Sun Mar 21, 2021 11:49 pm
As you may have guessed? I am a big fan of yours and Stephens work so to mess with the design too much would be Blasphemy!

However, I often thought that L7 (4 Turn coil) could be replaced as a transformer primary coupled to a secondary to drive the 2N4427?

You could use the transformer coupling method to drive the base of the '4427 - it works OK, but uses up board space somewhat. My earliest no-tune exciters used a ferrite bead for the coupling transformer, so it was very small. I also tried a single-ended half-frequency oscillator, and used a diode doubler to derive the output frequency, with transformer coupling of the output into the '4427.

You need a high-pass filter on the way into the '4427, so that the ½f doesn't get into the final stage. In the Pro III, there's a little coil on the output of the oscillator, which with its associated capacitor provides a high pass network.

You need a high-pass filter on the way into the '4427, so that the ½f doesn't get into the final stage. In the Pro III, there's a little coil on the output of the oscillator, which with its associated capacitor provides a high pass network.
informative .

Quick update!

I have tested the output power of the Exciter and it is doing a pretty steady 500mW across the whole band @ 13.8V

Also there is very little change in output @ 15V and the 4427 is running unusually cool?

After a bit of probing around? I have come to the conclusion that the oscillator is slightly under driving the 4427.

I suspect i will at some point have to upgrade the 78L08 (U5) and consequently the varicap bias divider (R17, R18)

A minor set back, But thats part of the fun!