[turretslug]

I was going to say, if you like the idea of a CR100 then by all means get one as it'll be good valve background and learning curve and at worst you won't lose a fortune- but you're one step ahead!

The first valve radio I ever overhauled (as opposed to ignorantly dismantling as a little 'un....) was a CR100, so there's a certain affinity. I'd played around with various domestic sets with the typical 6-18MHz SW band, mostly transistor portables but a few valve table radios/radiograms belonging to older relatives, and was hooked by this window on the world. Whatever was in all those other gaps between LW and 30MHz, oh to get hold of a real communications receiver. Reading the then-current electronic mags and books was discouraging, this was the late '70s/early '80s, i.e. peak "valve dissing"- they were fragile, wasteful, inefficient, dangerous, valve oscillators were uselessly unstable, valve mixers hopelessly noisy etc. etc., it seemed astonishing that anyone had ever been able to receive anything on a valve receiver! I had a little experience and a considerable hunch otherwise, though, and a good deal of sceptical stubbornness.

My physics lab at school was chucking out long-ignored and dusty old books by the hundredweight, including pre-war radio theory and practice books. I devoured these with fascination and it wasn't long before a local small-ad offered a CR100 from a down-sizing amateur. I went round, it was demonstrated working and I went home with hefty radio and an assortment of spare bottles. Undoing the base-plate and horror! crumbling rubber-insulated wire everywhere, including mains and HT AC feeds.... Nothing for it but a full re-wire and re-build. Over a couple of months, I did an hour or two every now and then, wire-wooling the bare chassis to a gleaming brightness and building it all up again starting from heater chain. IFTs and coil-boxes were scrubbed-up and rewired, and initial switch-on was joyfully flawless. My physics teacher lent me a prized PM5326 and a school lab Telequipment was quietly borrowed for a painstaking but absorbing and fruitful re-alignment. One thing that attracted me to the CR100 was the wide coverage and this set was no slouch, everything from the put-put-put on 60kHz to strong and clear 11m broadcasts came in well and consistently. It was always a drifter, though- fitting an 0B2 108V stabiliser greatly helped the short-term local oscillator stability and including the mixer screen-grid in this supply helped further, but long-term thermal drift was always a weakness. It really needed a couple of hours before SSB use became realistic. My main interest was international broadcast listening though, rather than amateur radio use, and the CR100 was great for that.

I actually still have it, in a corner of the (dry) garage, long-unused and embalmed in bin-bags and covered in component boxes and all the usual garage-fare. It was displaced by an AR88, probably a familiar story, its uncanny frequency stability contrasting with the steadily-wandering CR100. Must unravel it and power it up during these quiet times.