[SiriusHardware]

Originally Posted by Techman

I don't actually know. I'm hoping that you or someone else may be able to throw some light on that

Can't help you there, I'm afraid. From your photo it looks as though the legend on the smaller device has been deliberately obscured, or maybe it just has tape stuck over a window? If you can get any information off the chip maybe we can make an educated guess.

Originally Posted by Techman

The FM modification to the ‘059’ main board as used in the Ham-International Multimode 11, Jumbo, Major 588, is to modulate the VCO rather than the band crystals as in the original design.

Quite a common method - I think I remember doing that swapover on a 'Mufflemode'. Purpose made FM radios not only apply the modulation (deviation) to the VCO but intentionally run the VCO at half TX frequency so that any deviation applied to the VCO is doubled along with the VCO frequency - using that method, you don't have to wiggle the VCO frequency quite as hard as you would otherwise. The same technique works on handhelds which have crystal controlled channels - there the TX crystal is typically run at 1/2 TX and doubled or 1/3 TX and tripled.

Originally Posted by Techman

I really don’t know why I don’t do the FM power ‘mod’ by simply taking the feed from the bottom of the Darlington pair, it’s probably just a silly idea that I have that it puts stress on the component, and I just tend to do things the way I always did from back way back when. I probably ought to do it the Darlington way as it’s just a case of basically moving a wire.

I have to admit that Darlington always seems rather under-heatsinked to me. When operating in AM or FM mode in radios where both modes run on half-supply the Darlington is dissipating roughly the same wattage as the RF output transistor...only the RF output transistor has the benefit of being bolted to the chassis, whereas the Darlington typically has a heatsink hardly any larger than itself. It wouldn't take much to extend the leads of the Darlington to allow it to be mounted on the chassis for heatsinking purposes - I doubt the extended leads would cause any problems because that transistor only handles either steady DC (FM) or audio frequencies (AM).

Originally Posted by Techman

We would also go in between channels so that we could chat undisturbed on very low power.

Sounds as though you might have been better off using a pair of Tandy 49Mhz / 50mW walkie talkies - Only problem was, they used the same frequency as just about every analogue baby monitor on sale at the time. So even there you would have had a lot of fascinated listeners.

From your description of the characters around you it sounds as though CB in your area is still frozen somewhere in 1983 - it got like that around here to the point where I just didn't feel the need to be involved in it any more. After a brief revival of interest in the early nineties only to find that the worst aspects of CB still hadn't really gone away I decided, like many others at the time, to move sideways to amateur radio.

In doing so I just caught the tail end of the period when there were still a lot of old-school amateurs who were still quite techy / technically interested, and the repeaters were all still on enormous 900ft broadcast towers as this was before the government sold off all the transmitter sites into private hands, so even a newly licenced class 'B' operator with an ex-PMR handheld or mobile could typically work people in an 80 - 100 mile radius around their local repeater while they looked around for more sophisticated equipment. It was a good time to cross over, before the advent of easy, unrestricted internet communications sent amateur radio into its continuing slow-motion death dive.

That said, I never fell completely out of love with CB sets themselves or the actual idea of CB, which is why I still have most of the radios which I collected throughout the eighties and early nineties.

Originally Posted by Techman

A ‘local’ brought a York JCB 863 (Cybernet 134 chassis) round for me to look at last night.

That's a first for me, I've never heard of the controls seizing like that. The owner is to be commended for not shearing the control shaft off before you had a chance to look at it. I have a nice York 863 in my collection, but I don't have the correct York badged Cybernet coffin microphone for it, something which always irritates me. Nowadays I could probably just pick up any example of a coffin microphone and print a replica York badge for it - just one of many things I never get around to doing.