strange driver pll

[powerfull]

anyone seen this

http://www.ebay.co.uk/itm/FM-radio-tran ... Sw7FRWVxjh

[teckniqs]

Looks like the sort of thing you find in old PMR and pager transmitter gear, looking at the final output coils it looks like it could be for FM broadcast or be close to the band 2 range, what ever it is??

[shuffy]

Looks like there are 2 low power chains combining into a final. The chip on the left is an analogue switch (and dates the board to early 90's) would imagine this switches audio from distinct sources. As teckniqs says it's classic PMR but can't imagine what it might have been for...

[teckniqs]

I've seen very similar things, looks like the output is a 2N3375 or 2N3632 around 5 to 10w output.
I'd say it's probably as old as 1970s and it's something designed for lower band II (66-87.5MHz) PMR two way communications. Not worth wasting any time with and hardly even worth the eBay page that it was printed on.

[MiXiN]

This caught my eye a few days ago.

The Company who manufactured this or was the reseller, Bull Electrical, always advertised in various electronics magazines in the 90s - and is the "surplus electronics" store from which I bought my 1st ever 15W VFO Transmitter that got me on the air in 1994/1995.

Happy days!

[s2000]

There is an email address on the board so must of been around the 90s, yes they were definetely in the electronics mags. I remember them in Everyday Electronics magazine, now called Everyday Practical Electronics (EPE)...

[teckniqs]

Ahh fair enough, the old way it's laid out and the old components misled me to think it was an antique. So is it a VFO? What's the single chip for?

[shorty]

I'm guessing the ic is an audio amp so you could either choose mic or line audio in, bull electrical use to sell those 4w, 15w & 25w vfo kits in the late 80's and 90's, i got given the 15 watt kit to build for a friend who got it from them, it was mounted in a biscuit tin, it would drift around 1Mhz from cold, he used it twice then gave up on it, the output transistor and heatsink ended up been used in stable vfo rig.

[s2000]

The chip is a eqivalent of a CD4066A (Quad Bilateral Switch), I would imagine it is some kind of simple limiter or something.. I do vaguely seem to remember also something about a mic preamp being built in.

Yes my mate had the 3 watt pantek from them, it was awful you only had to breath on it and it would move a few Mhz!! We set it up on his roof as he lived on really high ground and did a few mixes, unfortunately the local neighbours started knocking on the door to say we were interfering with their tv's lol

[teckniqs]

Lol, yeah I used to do a similar thing and just kept on changing frequencies until the knocks stopped.

[MiXiN]

I'm guessing the ic is an audio amp so you could either choose mic or line audio in, bull electrical use to sell those 4w, 15w & 25w vfo kits in the late 80's and 90's, i got given the 15 watt kit to build for a friend who got it from them, it was mounted in a biscuit tin, it would drift around 1Mhz from cold, he used it twice then gave up on it, the output transistor and heatsink ended up been used in stable vfo rig.

Here we are - the exact 15W VFO that I bought from Bull Electrical, and you're right, they also sold a 4W and 25W version and still do on this website - http://www.smartkit.gr/fm-transmitter-1 ... ested.html

Can't believe Smartkits are still selling this shit 20+ years on, unless it's old stock that they can't sell!

[Maximus]

Yes it's the Smartkit sprogbox. I remember someone's comment from Whoslocked that something like "the DJ has to spend more time keeping the rig in tune than mixing the music".


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[MiXiN]

Yes it's the Smartkit sprogbox. I remember someone's comment from Whoslocked that something like "the DJ has to spend more time keeping the rig in tune than mixing the music".


Sent from my iPhone using Tapatalk

Hahahahaha, that's about right from what I remember of back in the day; I had one of those Optoelectronics Cub handheld frequency sniffers on the wall when I had my Smartkits 15W VFO and constantly had to monitor it.

After a few nights, it got to the point that we just used pre-recorded tapes as the multitasking got a bit too much - particularly when it was windy and the 1/4 wave homebrew GP moved that was mounted to 2 broom handles taped together wedged in the bedroom window.

Seriously funny looking back, but I could never go down that road again.

[yellowbeard]

Twelve trimmers, only one of them is SUPPOSED to control the frequency, you could spend an hour tuning it then it drifts 2MHz when you walk away. I have not seen a transistor in a TO50 package for a decade or two either - and is that a fiddle capacitor in the oscillator? Maybe not but it could be critical. This is like a young man's first car, the young man thinks it is his first love when he drives it but his dad finds it humiliating - but which one is shagging the lil schoolgirls?

[sinus trouble]

LOL twelve trimmers!! and each one would have to be tweaked atleast twice!! 24 trims and still not on frequency!! id rather try to solve the rubix cube than tune that thing!!