Anyone? FM VHF 88-108MHZ Exciter

HAS ANYOBE COMPARED ANY OF THE FOLLOWING
1w to 7w models Sinus /rev / driver board / pira / nrg pll pro III / zozo

I HAVE THE NRG PLL PRO 3, do any of the other exciters listed /(or any you can think of) exceed the NRG SPEC (if so in what areas?)

Thanks - over to the experts / enthusiasts

whats a good quality w to 5watt Exciter bump too ?-
As a lot of power amps require 5w input, other 4w, other 7w other 15w .... maybe need a good variable power

The "Sinus" and "Zozo" exciters are perfectly competent basic exciters, and if correctly assembled, correctly powered, and screened from the outside world, they'll perform perfectly well enough. The PLL IC they use may become difficult to source in future.

The PLL Pro III (if correctly assembled with care taken to ensure complete symmetry in the oscillator(s) stage) will have a better performance - higher power output, lower harmonics and spurs, and lowest carrier noise of any of the above. It's physically much bigger than the others, but doesn't use any specialist parts or pre-programmed microcontrollers. It is also much less prone to RF feedback hum problems and other instabilities because signal generation is at half the output frequency. It's best constructed without the RF output socket on the board - coax soldered to the output pads beneath the board is perfectly OK- which allows you to run the output either to a case-mounted socket or to a further amplifier. If you look beneath the board, you'll see that there are a pair of earth pads either side of the output transistor - if you couple those together with tinned copper wire - making certain that you don't short anything else on the board - you'll find that the power output increases to around 5 Watts right across the band!

I can't vouch for the "Rev" board (though it looks to be a competent job), but the Jan Kolar "Pira" effort works reasonably well, though its performance is almost entirely determined by the construction of the inter-stage coupling transformer and the careful alignment of the output stage trimmer capacitor. It also has the (minor) inconvenience of using an obsolete PLL IC (which will be difficult to find in future) and the firmware forces a "re-tune" every half-hour, which can put small noise bursts on the carrier.

There are other exciter products about (like the Ebay ones from Greece) which all work reasonably well, but are relatively expensive and almost impossible to repair if something goes wrong.

None of the Chinese "FM sender IC"-based rigs are any good. Most of them are so bad that they'll cause massive local interference because of their ridiculously dreadful spurious suppression, so you're likely to get an "unfriendly visit" much sooner if you use one of these awful things. Do not believe the RF spectra shown in many of these adverts - they're certain to be bogus!

Interesting

Yup, never trust Chinese transmitters

Thanks for the suggestion about the pll pro rf socked, why would using an external socket to case be better ? It it something about the pcb socket being there next to the coils that causes the issue?

Does the zozo board have to been boxed in a tin to work properly?

Ive used the zozo with a 100w amp and aerial a few feet away with no problems. Just needs a normal metal project box

LeeCavanagh wrote: ↑Sun Jan 22, 2023 9:56 am Interesting

Yup, never trust Chinese transmitters

Thanks for the suggestion about the pll pro rf socked, why would using an external socket to case be better ? It it something about the pcb socket being there next to the coils that causes the issue?

No. I just found that having the SO239 socket on the board necessitated the addition of a physically big PL259 plug to connect to it, which would take up a lot of the space inside the box!

There is still the heat sink on the transistor tho, but fair enough, so soldering a link on those pads works when the pl plug is still there - that makes sense (although why were they sold as 4w rather than defaulting to 5w?

Albert H wrote: ↑Sun Jan 22, 2023 1:30 am The PLL Pro III

the Jan Kolar "Pira" effort works reasonably well, though its performance is almost entirely determined by the construction of the inter-stage coupling transformer and the careful alignment of the output stage trimmer capacitor. It also has the (minor) inconvenience of using an obsolete PLL IC (which will be difficult to find in future) and the firmware forces a "re-tune" every half-hour, which can put small noise bursts on the carrier.

There are other exciter products about (like the Ebay ones from Greece) which all work reasonably well, but are relatively expensive and almost impossible to repair if something goes wrong.

None of the Chinese "FM sender IC"-based rigs are any good. Most of them are so bad that they'll cause massive local interference because of their ridiculously dreadful spurious suppression, so you're likely to get an "unfriendly visit" much sooner if you use one of these awful things. Do not believe the RF spectra shown in many of these adverts - they're certain to be bogus!

Veronica PLL is absolutely the best but need a redesign and another type of amplifying, is needed to make it more compact and more efficient.

pira loop. I do not noticed in 78h run... and i do not see this in pira code... now use for tune SDA communication with pic16F628
For next 10 20 years i do not see any problem we to be without TSA5511 and PIC16F family

only close to be good IC from china is qn8007 for sure

greek guy yes https://jpl995.storenvy.com/collections ... ransmitter

The Pro III exciter, with a 1971 final, and a two-chip PLL is probably the way to go!

Albert H wrote: ↑Wed Jan 25, 2023 4:15 am The Pro III exciter, with a 1971 final, and a two-chip PLL is probably the way to go!

it's time to realize that too

Rigmo
I'll be in touch with some suggestions for your update.

Albert H wrote: ↑Thu Jan 26, 2023 12:50 am Rigmo
I'll be in touch with some suggestions for your update.

Sounds interesting.

I tested the Zozo design it worked well.
I found it to have quite a strong 3rd harmonic into the aircraft and 2meter ham band.
If not aligned correctly with my spectrum analyser.
So it could do with better filtering around the doubler stage.
I found the final harmonic filter works OK above 180 mhz...
So If you don't own a spectrum or wave meter, I would avoid using this design and go for a NRG or Veronica kit.

I didn't think the Zozo board had a doubler ?
It's broadband transformer coupled (a la BW / SBS), right ?

Yeah there's no doubler on the zozo board. What your seeing is probably just harmonics because there's no real filtering. The LC circuit on the output is more just for impedance matching.

In general I wouldn't recommend running any exciter direct into an aerial without a separate filter because almost no exciter design has enough filtering built in. But thats because they're designed for driving a power amp, which will catch the harmonics in its own filter.

A Band II, at frequency design, can’t produce harmonics in the air band or 2M amateur band. That’s not necessarily to say it can’t produce output in those areas, but they are not harmonically reflated to the intended output frequency (or to the oscillator frequency, which are one and the same).

the most i have achieved with on the v1.0 Pira5w 2023 pcb board is the following:
13.800V @45°C almost 6W clean out.

Shedbuilt wrote: ↑Sat Feb 11, 2023 7:47 pm A Band II, at frequency design, can’t produce harmonics in the air band or 2M amateur band. That’s not necessarily to say it can’t produce output in those areas, but they are not harmonically reflated to the intended output frequency (or to the oscillator frequency, which are one and the same).

it really can!

rigmo wrote: ↑Sat Feb 11, 2023 10:35 pm

Shedbuilt wrote: ↑Sat Feb 11, 2023 7:47 pm A Band II, at frequency design, can’t produce harmonics in the air band or 2M amateur band. That’s not necessarily to say it can’t produce output in those areas, but they are not harmonically reflated to the intended output frequency (or to the oscillator frequency, which are one and the same).

it really can!

That’s kind of my point. If the oscillator is on frequency, and the PA too, then any outputs between f and 2f are not harmonics (at least not harmonics of the intended / oscillator frequency). They are either spurious emissions, harmonics of spurious emissions, mixing products of spurious emissions wuth intentionally generated frequencies, and various other permutations of the above.

Those additional outputs are spurs - usually caused by self-oscillation of mismatched stages. That self-oscillation is usually at a few tens of MHz, so you'll see all sorts of products between the carrier and 2f (and beyond!)