Not been here for a good long while, everyone cool?

Been out the country without internet last few weeks and had some time to work on that old exciter board project that neve got finished.

Finally come up with something working really nice.

Basiclly everybody seems to love the NRG stuff so as we never come up with an easy notune doubler on our last attempt I decided to use the good old NRG oscillator (colpitts I believe?), through first stage then a rf transformer(easy to make) to a 1971 and stripline broadband match on output.. Its giving a nice even power acrooss the band (peaking slightly at around 99mhz) and capable of about 8 watts which ive put jumpers and a variable power pot on. 1 watt jumper, 5 watt, 8 watt, then the variable pot can be used which maxes out at the selected power by jumper. Ive toyed with the oscillator being in small stripline coils, works very well and very very stable but at 50mhz signal is a little high, im yet to test it with the wire wound coils in osc, either way it takes up same space on pcb.

Now firstly does anybody have hex file for a motorola mc145170 to use dipswitch settings, would really like to use this because of the out of lock output. Ive 100% decided on dipswitches to set frequency, that up/down button shit is a pain in the ass.. alternativly i can use Saa1057 but im struggling with the unreliable out of lock output.
The SAA1057 pulses the test pin and the pulse get slower as you get close to lock. However on the chips i have it only pulses if the oscillator is tuned below the pll set frequency, and it just pulls low without pulses if the osc is above the pll set frequency. It pulls the output low and goes high on each pulse(with aid of a pull up resistor), ive managed to lose the pulses using around 150uf cap but it takes to long to discharge the cap to switch transistor off as i wanted it to have a lock light similar to the NRG boards to assist with tuning. Now the BIG problem is, if you go near the pcb, or overmodulate the saa randomly pulses here and there knock the transistor out of lock, so its not ideal for the average hobby user.

SO here what i propose.... tell me what you think.
I was going to use a dual comparator which monitors tuning volatge, if voltage above say 3v and below 5v then it gives a lock output. The saa1057 will only ever give that volatge out if its locked otherwise it will be out of this range sitting at either 0v or 12v, would this class a good enough out of lock system? its working very very well on bench. Ive added hysterisis to stop flicker when at 3v or 5v.. What do you guys think?

The board is a fair bit smaller than half the size of an NRG 4watter.

Ive not used the PNP transistor to modulate the audio as NRG do, I dont like it, as pll voltage rises it distorts the audio into base of transistor, its fine at 3.5v below so no good for the pll im using. Also the modulation is low on the NRG boards, ive never found it loud enough, so ive fixed that to.

Im not worried about including 'out of lock power down'... They are never going to be used commercially, is it really needed? Would be a nice feature I guess

Greetings Mr Berlin!
I loved the "Radionecks Exciter" that you, Albert and other users came up with! it was a shame to see it never completed!!
Anyways not that im much help? but ive used the SAA1057 in all my projects in conjuction with NRG exciters and theyve had me pulling my hair out!! especially a lock indicator!! lol
I did manage to get the the nrg to lock without tuning? but only by supplying the SAA1057 with 30v :/
Ive tried comparators etc for lock indicator but still no precise indication??
The only configuration ive found that was half decent is this....

Although ive never had any serious problems locking an NRG with the SAA1057
The loop can be unstable with large capacitance in circuit! (Eg Audio caps)
As im sure youve mentioned before? separate varicaps for audio and tuning would be a better option!

Thanks, Ill give it a go tomor.
The problem with using diodes to swing the entire band is that it introduces some background hiss, to sensitive. Ive tried various options such as a couple of varicaps in pararell but everytime i get the hiss however i configure it. I tried a simple voltage doubler and using a transistor to drag it down to ground to lower voltage but again got he hiss. So im going to add a small trimmer just for the osc with single varicap for pll tuning, the rf amplifaction will be no tune. I will just put a small pad where you can stick your multimeter prong in to allign the tuning to centre the pll voltage "set at 5v" for example.... nice and simlpe that way and less component count. If you cant do that simlple alignment with a multimeter then you shouldnt be building this kit is my theory...

Lol yeah i agree! My Pll Boards are a piece of piss to setup! No frills No gadgets just basic skills to get optimum tuning voltage and audio quality!! No indicator is perfect!

Both 1 and 10 Watt Free Radio Berkeley PLL's use that arrangement of MC145170 with dip switch and a PIC16F628. I have never seen one in the flesh, but maybe that detail will jog someone's memory and get them rooting thru their bits and bobs?

Thanks, ill take a look

Boards are finished people.. Just waiting for them to arrive
Size was a little bigger than I wanted but its a nice easy kit to build. They measure 70mm x 150mm but it not bad considering its got a 8w amp and heatsink onboard.
I had to settle for the Pira Pll and added comparator to monitor tuning voltage to simulate if locked or unlocked. I used the pics's tuning cycle output to trigger the exciter on,this way I didnt get an RF spike at first switch on before a lock is established, if tuning voltage is to low or high it goes unlocked and powers down.
I added 3 jumpers for power, 0-1w, 0-4w, 0-8w and each can be varied using pot. I used jumpers so that beginners without power meters didnt risk blowing up amps with say max 1w inputs.
I really have worked hard on this, getting the layout with a half decent ground plane without a massive pcb took me ages. Ive based it around the old NRG 4watt boards as in design for oscillator but used a transformer and 1971 on output
It has PLL lock led, RF Power led, Pre Empth, and all the usual shit!

Anyway as soon as they arrive i would like to send some kits out for half their cost just to get some good feedback and reviews and it would be nice if some people who have decent analysers could measure the harmonics properly for me, im not exaclty sure how to get accurate readings from my analyser, however I know whats acceptable and these are well within spec! So please PM me if you would like me to send you a kit, obvisouly just expect postage and a few of the components to be covered, im not worried about resistors caps etc.

Once they are complete ill stick a few bits on ebay and in online shop. But im very happy with them and they are looking good I think.

oh and just to piss you all off, it has an so239 connector on board hahahahah...
however it has solder pads underneath if you decide not to install it.
If I removed it from the PCB it didnt make the pcb much smaller due to the rest of the layout so i kept it on there.. Good for a beginner!

I'd be happy to try one of your kits and give you some feedback if you'd like?

Yeah no proba analyser, I'll drop you a pm

Heres some radio porn.... A sneak preview..... Not built yet as im abroad and dont have all the stuff with me. As soon as I build first one ill post some pics. Ignore the website on it, its not up n running yet, just have my rds stuff on there for time being...

The large tin plated area is where the heatsinks sits with 3 self tppers from underneath the board (2 eitherside of the rf transistor for good grounding). There is pre-empth jumpers, power jumpers and power pot, usual rf dc and lock leds. Fingers crossed that I didnt make any mistakes as i didnt etch one up before manufcture ... to much hassle lol .. The pic has uploaded shit quality, but writting on the left says "RIP Stephen 'NRG' Moss - A True Radio Legend".. Thought id pay some respect as used his oscillator

So, when are you going to be selling these?

Hi all! Berlin, what ratio are you using on that transformer? And what drives it? Is that early RDVV output stage?

If I had not just bought two of Dutch RF shop 6 watts I would have one. Be a month or so before I need another driver, what is the ballpark full price going to be?

pjeva wrote:Hi all! Berlin, what ratio are you using on that transformer? And what drives it? Is that early RDVV output stage?

transformer is 2:1 and a 4427 drives it but running down at 9volts

No its not RDVV, its slighly wider and longer, its stripline ive been using for years and years that I once used to match a blf244 input, just made it a little longer until i got the results i wanted. However I did this on FR4 copperclad, so im hoping the manufactured pcb's have same properties for the stripline

The price will be be very very affordable, no silly markups like the existing NRG pcb's. Should be well under 50 quid