nrg kit pll

[LeeCavanagh]

Cool. Thanks, always good to fill in the gaps

[rigmo]

Yes. It was my design.

Dear Albert why you never used MC145152P2 instead all this ICs, can use ALF

[shorty]

Yes. It was my design.

Dear Albert why you never used MC145152P2 instead all this ICs, can use ALF

Back in the day i asked Stephen the same question, Price, they were more expensive compared to the individual ic's used, he always made value for money equipment.

[rigmo]

Back in the day i asked Stephen the same question, Price, they were more expensive compared to the individual ic's used, he always made value for money equipment.

sure,,,
I believe that today MC145152P2 it is cheaper and there is less possibility of error.. a smaller PCB

[Albert H]

We did use the Motorola ICs, but at the time they were very expensive. The discrete logic PLL in the Pro III cost around £3.20 in parts (at the time) whereas the just MC145152 (which also needs a prescaler) cost around £9.50! There were further problems with the big Motorola PLLs - it was a nightmare for a beginner to be sure to get all the pins in the holes at the same time, and the IC wouldn't work reliably if it was raised off the board by an IC socket. They also needed more expensive crystals, and the board layout to get the programming pins in a sensible order on the switches wasn't trivial with a single-sided PCB!

Steven and I did several alternative PLL designs,and all the time he resisted the PIC & PLL chip approach, because he insisted on generic components available anywhere.

Other add-ons I did for the Pro III board included a composite multiplex (final) limiter (which would allow you to push the average mod level up quite a bit without overdeviation), an LED frequency display (which was multiplexed using an output from the 4060), and a varicap bias voltage multiplier, which allowed a 33V swing across the varicaps, eliminating the VCO trimmer capacitor!

I also did a version of the Pro IV stereo coder that included a gyrator-based replacement for the 15 kHz Toko block filters that we'd always used, and had the same footprint as the exciter, There was also a stereo audio processor with pre-emphasis in the same footprint. We were thinking of a sort of "sandwich" construction layout with earthed screens between boards, and a mains power supply module (that would have been supplied ready-built), so that there could be a "one box" complete transmitter.

The final pieces of the jigsaw were the link receiver and link transmitter - both again with the same footprint (the Link Tx was actually a variant of the Pro III tuned down to Band I) and the receiver would have had carrier and tone detect for rig switching. The audio processor and stereo coder would have optionally been fitted into a link transmitter in most cases, with the link receiver beneath the main rig exciter board.

There were also a series of PAs - with plans to go up to about 400W (about as big as you could go with the FETs available at the time).

We were also considering our own design of enclosures for the gear, so we could stop using those horrible vinyl-covered monstrosities from Craplin!

We also contemplated a range of studio gear - a basic stereo mixer with four music channels and two pannable microphone channels with compressors built-in was my first design in that series. There was also to be a jingle player and a few other goodies too.

[shorty]

We were also considering our own design of enclosures for the gear, so we could stop using those horrible vinyl-covered monstrosities from Craplin!

Steve use to have an aluminium enclosure manufactured that he designed to house the 75W & 150W transmitters from memory they were a nice box, not sure why he stopped using them, he then move onto using two of the vinyl box's screwed together.

[Albert H]

The problem was getting them made at a reasonable price.

We did make a few rigs (mostly for RSLs) in 19" rack boxes, but the boxes (from Farnell) cost about the same as the rest of the rig!

It was all about economics. The equipment had to be reasonably inexpensive (especially if it was going to be "lost" up tower blocks), but the performance had to be better than most. The doubler exciter was a particularly nifty design, and was capable of very high purity, with low phase noise, no spurs, low harmonic content, and low audio distortion. The aim was always to have such a clean carrier that tuning through it (when there wasn't any mod) would just sound like a "hole" in the white noise!

The other aim was to make the construction of the gear possible for someone with limited tools, experience and knowledge, but with an ability to solder neatly. I think that we achieved that - the PLL Pro III was built by hundreds (thousands?) of people, and very few of them needed to use the "get you going" backup support service that Stephen offered.

There were just two things that Stephen didn't want the home constructors making for themselves: Mains Power Supplies and RF Power Amplifiers. We didn't want beginners building Mains Supplies, because getting them wrong could potentially be lethal. We didn't want to supply kit PAs because most home constructors wouldn't have the test equipment to align them correctly, and unless they were set up properly, they could generate a lot of interference. Stephen just supplied pre-built and aligned PAs.

I did develop a little 15 Watt PA that used a pair of 2SC1971s - 1 Watt in from a Pro II or Pro III exciter, and a no-tune 15 Watts out at 15V supply- and we'd planned to offer it as a kit, because it didn't require alignment, and was remarkably clean. The purity was partly because of the push-pull topology - even harmonics tended to cancel, so the first significant harmonic that needed to be stripped off was the third. The lowpass filter on the board turned over at about 145 MHz, and higher harmonics were all well suppressed. At 15 Watts out, and at the low end of the band (the worst case), there were no harmonics worse than -68dBc. I did a PCB layout, and we etched a couple of prototypes and found that they worked flawlessy. Unfortunately, Stephen died before we could start shipping the kits.

[rigmo]

I did develop a little 15 Watt PA that used a pair of 2SC1971s - 1 Watt in from a Pro II or Pro III exciter, and a no-tune 15 Watts out at 15V supply- and we'd planned to offer it as a kit, because it didn't require alignment, and was remarkably clean. The purity was partly because of the push-pull topology - even harmonics tended to cancel, so the first significant harmonic that needed to be stripped off was the third. The lowpass filter on the board turned over at about 145 MHz, and higher harmonics were all well suppressed. At 15 Watts out, and at the low end of the band (the worst case), there were no harmonics worse than -68dBc. I did a PCB layout, and we etched a couple of prototypes and found that they worked flawlessy. Unfortunately, Stephen died before we could start shipping the kits.

made by RF Master Antonius Jalu

[radium98]

rigmo thoses red cable are 50 or 25 ohms ?

[rigmo]

rigmo thoses red cable are 50 or 25 ohms ?

and how else

[radium98]

???