Old Rig

[Albert H]

I found a couple of old rigs in a box in my garage yesterday. I'll take a couple of photos later, and post them up here.

[teckniqs]

I found a couple of old rigs in a box in my garage yesterday. I'll take a couple of photos later, and post them up here.

We've been waiting over 6 months, how much later did you mean?

[Albert H]

I've been VERY busy (and ill!)

[tvtv]

Didn’t stop you posting some other lengthy replies and threads on this board in between starting this thread and now. Common theme that , but that’s ok, I don’t care much for whatever is in your garage. I do hope you feel better soon though

[teckniqs]

Get well soon Albert. We look forward to your recovery and finally seeing them if you care to post them.

...@tvtv, a little harsh but I can understand the frustration lol

[jvok]

Having a clear out and found some bits from the first rig I built around age 17.

stereo.jpg

Switching stereo coder using a 555 timer as 76kHz oscillator, 4013 divider to get 19 and 38kHz, 4066 (I think) as switching mod which I must have stolen for something else at some point, and TL072 as preemphasis. Vaguely remember design I copied used a 2.432MHz xtal and 4060 as divider but I had no idea where to buy the xtal (couldn't get them at maplin) so I redesigned it using the 555 instead. Of course it drifted like a bitch so I ended up swapping in the expensive silver mica cap to get it stable. Just for gits and shiggles I fired it up and it came up on 38.15kHz so obviously drifted a bit since then.

vfo.jpg

2-transistor VFO (oscillator and buffer) think it gave about 50mW on a good day although the only way I had to measure it was a peak detector feeding a multimeter so could have been way off. Remember it being fairly stable for a vfo. This one fired up on 105.7 (+3kHz off) but don't remember why I set it to that, when I was using it in anger it would have been on 93-94ish which was a clear spot in the band back then in the Wirral area.

1w pa.jpg

"1W" PA using a badly overrun 2N3866 which got red hot and never worked that well. Used to just about cover the neighbourhood with that into a shoddy dipole made from copper pipe I stole from my dads shed. Probably wouldve got a bit further if I'd had a decent site to run it from, anyone who knows the wirral knows most of it is fairly flat. Think I spent more time building this than I actually did on air lol.

Seem to remember this lot originally had UHF TV connectors for the coax back in the day, mustve changed them to BNCs later on, maybe in my early 20s when I finally got hold of a second hand scope.

Goes without saying my builds are a lot neater nowadays but I caught the bug from this and doubt I'd be on here now if it wasn't for this little attempt at setting up a station.

[Albert H]

TX_PLL.jpg

TX_Overview.jpg

TX_Interior_(Built_in_a_Hurry!).jpg

Some Band 1 link gear from about 1981

[Albert H]

RX_Input_End.jpg

RX_Interior_Overview.jpg

Here's the other end....

It was all thrown together to help out a well-known North London station. They'd been raided and were promoting some event and were desperate to get back on, so I built them some Band 1 Link gear (two transmitters and 5 receivers as I recall) and half-a-dozen Band II PLL rigs, each doing 90 - 100 Watts.

The rigs were built using my cheapo PLL exciter (I used to keep a couple of dozen in stock!)

It was a busy day! They were back on from a different site after about 4 hours, and got raided again that evening, but were back on that second time in about 30 minutes!

[Albert H]

There's also an ancient Band II rig, but it's not worth photographing as it's just a redundant Pye Band II Police base station, with the AM modulator ripped out and the original PA fed from a little PLL exciter PCB. The PA used an SD1019 output transistor, and if run at about 29V supply - with a fan cooling the heatsink because it wasn't meant to be at full power all the time (these were AM boxes, remember) - they'd do around the magic 100 Watts. The complete ex-Plod rigs were available on the surplus market for less than the price of the output transistor! I remember driving home with twenty of them in my boot!

[teckniqs]

How do you keep something from 1981 in such prestine condition like this?

.....It looks like it was built last week!

[RF-Head]

it's mutch newer dan 1981
look at the ic's and transistors!
Also the 100NF multilayer capacitors are mutch newer for what i can see more like beginning 2000

[EFR]

it's mutch newer dan 1981
look at the ic's and transistors!
Also the 100NF multilayer capacitors are mutch newer for what i can see more like beginning 2000

I have seen these blue plobs on early 1990 professional gear.

[Albert H]

Head - I was using the little blue capacitors from the late 70s. I had three bags of them (each bag contained around 5000 pieces) that were bought from a surplus company by weight! There were 10n, 47n and 100n and rated at 50V. They were great to use because they were so small!

What you can't see in the receiver is that there's a simple AFC loop tacked to the underside of the PCB. It used a varicap to keep the oscillator tied to the incoming signal and avoid thermal drift problems. It's a simple receiver, but really reliable!

The gear is all so clean because it was all wrapped for storage when we moved house some years ago.

That gear was from February 1982 (I just checked).

[Albert H]

Incidentally, I've just sold off some old gear this morning. Again, nothing much to look at - a 1kW Band II rig in 19" cases. There's a 1U exciter / stereo coder / composite clipper, a 3U PA, a 4U power supply (that's really heavy because of the toroid transformers and filter capacitors), and an audio processor in a 2U case. There was also a rack frame with ducted cooling to house it all. It's gone to replace a Bext rig somewhere in Eastern Europe.

That gear is going to pay for a nice trip away (Vienna, probably) for the Boss and me!

[Wk-end]

If you have more bits like that please pm me first fella! Nice one. x

[Krakatoa]

it's mutch newer dan 1981
look at the ic's and transistors!
Also the 100NF multilayer capacitors are mutch newer for what i can see more like beginning 2000

I have seen these blue plobs on early 1990 professional gear.

And I haven't seen the Philips silver-faced BF199's until the 90's (look at the second photo of the driver board).
To me, yeah, early to mid 90's.

[jvok]

If you zoom in on the left hand chip on the PLL board you can just about make out "MC74HC4060N". 1981/82 seems too early for 74HC logic, for that era I'd still expect 74LS or original 7400 (with no letters). If you believe wikipedia 74HC wasn't available until 1983. Plus I don't think the 74HC reimplementations of the 4000 series chips came until later.

A proper photo of the PLL board with the date codes visible would prove it either way.

[shuffy]

Lots of intrigue here ! I can't make out a single date code anywhere apart from the 3 digit one on the CA3089. Inconclusive as these came out in the early 70s but given the "look" of the other components, I'd guess at 86. @Albert if you had gone about 4mm to the left on the PLL pic, the date code on your 78M12 would be visible

I remember the larger blue ceramics from the 80s. I had a ton of yellow ones identical shape and markings to the smaller blue ones.

jvok I did a 555/4013/4066 coder like yours at roughly the same age, and also had varying degrees of success with the 2N3866 (relatively easy for a kid to get hold of in the 80s but I was hopeless as I just used to run everything at 12V and you need 28V to get any useful gain out of that device). I see you biased yours out of class C - 50mW drive wouldn't have given you much action otherwise even at 28V!

I tell you what, at least people are posting something. I've only got one early rig that's intact and it's pretty much just modifed PMR, so not posting that!

[Albert H]

I've got an HP 141 series analyser from 1979 that has 74HCT Motorola and Texas logic ICs in its counter, and a DEC Vax Mini that 's from 1980 with 74HCT logic in it. That Vax was built for the American military, and they were all made obsolete in 1989 when they moved to PC derivatives, and they were sold off to educational institutions for pennies.

My earliest PLLs for Band II used 74-series TTL, with ECL (Plessey) prescalers. The phase comparator was a 7474 and 7400, and gave locked / unlocked outputs as well as phase pulses to feed the loop filter. The dividers were (usually) 7490s hard-wired to give the required (fixed) division ratios. The very earliest of these was 1973 (pre-ECL), and used a row of transistor bistables to divide the 22 MHz VCO down to the point at which the TTL would clock. The 22 MHz was then doubled and doubled again to get to Band II. The ~100mW from the buffer stage after the second doubler drove a couple of valved stages to get to useful power (80W as I recall). That was the first FM rig I built that was really frequency stable!

[EFR]

Original 7400 logic family started around mid sixties (from my head, maybe 1965 or 1966?). Earliest 74H chips what I have seen, are from mid seventies, and earliest HCT what I did find my junkpile was dated 8216, it is on PCB from old military radar...