Hello everyone!

I need some guidance on my next purchase for some gear.

I currently have a few "transmitter on a chip" solutions (QN8066 and BH1417) that I've bought/built and I'm looking for something "different." By that, I mean possible improved transmission quality both in audio and rf as opposed to more power (I'm perfectly happy in QRP territory). I really like the idea of an exciter PLL that is as "discrete" as possible as many solutions seem to boast very good characteristics not to mention an opportunity to build/learn something along the way. I have found many options, but each comes with its challenges:

• The NRG boards I've found- the Pro5 and Pro6- may or may not be still available (I can't get any response from the company that may or may not have them) but if I did my research right they are top notch.

• There is a kit I saw from dutch rf shop that ticks all the boxes and I like that I can dial the watts down from 6 all the way to 0 if I want, but I haven't been able to search concretely just how good the transmission signal (spurs or lack thereof) is.

• A kit I saw from another Dutch radio shop has a couple of nice kits with a fairly discrete PLL/VCO section but they say they only provide the kits no schematics, instructions, or support. Makes me la little leery should I run into a problem.

• I found the Pira design, but it requires you to etch your own PCB which I haven't done since high school and hence I have nothing on hand to do so.

• The "One Last FM Exciter" by zozo here seems like a fun project and I probably have close to all the parts on hand to build it so that seems promising. However, I don't own a PIC programmer (I imagine they're not expensive or hard to get, but at this time I don't have one).

There is one solution I found out there that is a "no code" PLL that implements via hardware only, but based on what I read in my research I do not want to do business with that company based on how he treated former business partners.

I know that these options when it comes to audio quality will have a strong encoder component (which will probably be another thread entirely) but from a transmission quality and learning standpoint does anyone have any input? To be honest I'm leaning toward the DRFS06 kit from dutch rf shop because it seems very similar in layout to the pira (so no having to etch my own board), comes with a schematic and seems to be a smoking deal for the price. That being said, I'm open to other options not mentioned here. I also don't mind if a design suggestion requires one or two parts made from unobtainium as you never know when a gem will show up on ebay provided I don't have to sell my other kidney to get it.

Thanks in advance, and I'll start a separate thread for stereo encoders/RDS (unless someone has some advice here).

Greetings!

The Sinus PLL is free to download, Zozo PLL and also Rev PLLs are available too!

Good Luck!

Oh i forgot your PLL sinus! I saw that one here too but it slipped my mind.

I take it yours along with the other solutions I posted above are going to outperform a SoC (Station on a Chip)?

They certainly will, if built properly!

Look at the "Rev" exciter if you don't want to programme PICs, but a PIC programmer can be as little as £10 (or much less if you build your own).

Hi Albert!

I'm trying to find Rev's exciter here, but I'm not having any luck so I can take a look at it. Can you help? I found a few finished boards in the FS section but that's it.

FourierFun wrote: ↑Tue Aug 23, 2022 5:09 am Hi Albert!

I'm trying to find Rev's exciter here, but I'm not having any luck so I can take a look at it. Can you help? I found a few finished boards in the FS section but that's it.

It's in here:
viewtopic.php?f=11&t=2818
Ifn you drop Rev a PM he may help you out - or maybe not... He is a regular, so you won't be waiting long.

FourierFun wrote: ↑Tue Aug 23, 2022 5:09 am Hi Albert!

I'm trying to find Rev's exciter here, but I'm not having any luck so I can take a look at it. Can you help? I found a few finished boards in the FS section but that's it.

Hi FF,

I have plenty of kits available if you want to build your own. Take a look at http://zynq.uk/tx/ to see some of the instruction manuals. PM me for more details.

Rev

Thank you all for your help and feedback! Glad to see such positive feedback on my choices (as well as help with finding others). I'll post up pics when I have kit in hand!

Rev, Sinus and zozo are all nice builds. You can’t go wrong with any of them.

The "Rev" exciter has the advantage of starting at half frequency. This means that RF feedback from the output to the oscillator doesn't happen, and so it's less prone to hum. I had one here a while ago that was feeding a nice MRF101 PA, and giving just over 90 Watts on 92.4 MHz. The spectral purity of the rig was very good, and it had a nicely quiet carrier. The owner of the rig wanted a Band V link receiver and remote switching added - the rig itself was working perfectly.

Just for amusement, I set the rig to the bottom, middle and upper parts of the band, and the exciter (after a small tweak of the VCO trimmer) locked reliably after a few seconds in each case. The output power didn't vary much across the band (I tested at 88, 96 and 101 MHz) - about 2½ Watts more at the bottom end - and the purity was good in every case.

Albert H wrote: ↑Tue Aug 23, 2022 8:50 pm The "Rev" exciter has the advantage of starting at half frequency. This means that RF feedback from the output to the oscillator doesn't happen, and so it's less prone to hum. I had one here a while ago that was feeding a nice MRF101 PA, and giving just over 90 Watts on 92.4 MHz. The spectral purity of the rig was very good, and it had a nicely quiet carrier. The owner of the rig wanted a Band V link receiver and remote switching added - the rig itself was working perfectly.

Just for amusement, I set the rig to the bottom, middle and upper parts of the band, and the exciter (after a small tweak of the VCO trimmer) locked reliably after a few seconds in each case. The output power didn't vary much across the band (I tested at 88, 96 and 101 MHz) - about 2½ Watts more at the bottom end - and the purity was good in every case.

Thanks for the feedback Albert! To be honest, that design direction is the path I wanted to try first and then buy one of the other offerings from members here after that. I've already looked into PIC controllers and yes, it seems pretty cheap to get started on that route.

I really can't thank you all enough for your advice and feedback. It is truly appreciated!

https://www.amateurradioshop.nl/webshop ... r-kit.html


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Maximus wrote: ↑Wed Aug 24, 2022 9:42 am https://www.amateurradioshop.nl/webshop ... r-kit.html


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Thanks for the recommendation! Unfortunately I have decided to pursue another route instead of one from amateur radio shop. I was a bit leery of no circuit diagrams, instructions, or support so I went a different route. I appreciate the thought though!

The Dutch one has a nicely silk-screened board, with all the components clearly marked. It's really easy to construct!

Reverend's (REV) driver boards are excellent, a good price, and he always sends in a timely manner.

I have a few of his boards here & they're superb.

Albert H wrote: ↑Thu Aug 25, 2022 4:01 am The Dutch one has a nicely silk-screened board, with all the components clearly marked. It's really easy to construct!

Well since none of the options I'm looking at really break the bank, there's no reason not to try one in the future

MiXiN wrote: ↑Thu Aug 25, 2022 4:51 am Reverend's (REV) driver boards are excellent, a good price, and he always sends in a timely manner.

I have a few of his boards here & they're superb.

Another vote of confidence! I like it!

If your main concern is interfering with other fm stations you might try using a max2870 pll, i’ve been using it, its fairly good the harmonics are abit stronger than the 8066 chip, you can make a filter quite easyly, it dose about 1.5w with my 2.5w amplifier, compared to a chip it produces no noise over the fm band, there are a few small spuri on some frequencies, with the aerial less than 10 meters away, I can still recieive all fm stations if its located either end of the band. You don’t exactly get full bass, it is hard to solder the audio in which I had to find by trial an error. It dosen’t produce stereo you can generate in stereo tool.

reverend wrote: ↑Tue Aug 23, 2022 7:13 am Hi FF,

I have plenty of kits available if you want to build your own. Take a look at http://zynq.uk/tx/ to see some of the instruction manuals. PM me for more details.

Rev

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