That commercial winding machine reminds me of the bobbins I wound on a primitive setup, a modified lathe with a variable voltage DC motor speed control. Toroids were wound using an odd looking machine with a shuttle and slider, also variable DC motor control. I made so many mistakes I nearly got fired but reminded the boss "I applied for the testing department so why did you put me in winding?" The next day I was a QC/QA tech doing in process and final testing, also working on R&D with engineering where I was happy as a clam for the next 7 years.
You don't need iron from a Hudson to wind mod transformers, they don't contain silicon steel anyway. Peter W. Dahl bragged about the superior qualities of his "Hypersil" when transformer lams are silicon steel to begin with, something they don't tell you in tech school. Power transformers work surprisingly well once you choose the proper turns ratio using a little Greek math to determine the impedance transformation ratio. Transformers don't have a characteristic impedance, they transform impedance or in other words primary impedance depends on secondary load impedance which in mod iron is typically around 4K. Again it's Greek math, I forgot the formula but it has something to do with the voltage to current ratio in the FPA. Uh uh, I don't have a BSEE, I'm a technician, not a magician. (Saw that on a fellow tech's license plate holder on his car.) One thing is for sure, you need heavy metal to make angel music, vintage rigs aren't called boat anchors for nothing. It took an Iron Butterfly to sing I Na Gadda Digestion <burp> and a Led Zeppelin to buy her Stairway To Heaven. If there's a bustle in your hedge row don't be alarmed at, it's just a spring clean for the May Queen. Play it backwards to hear the Satanic message. (;->)
Before I leave I should remind you that when you machine wind coils for RF leave a few days for winding stresses to relax before tuning them on a Q meter prior to installing them. Didn't anybody tell you every coil and RF coupling transformer is pre-tuned before mounting and wave soldering the boards? Do you REALLY think your rig was aligned as an assembled unit? <giggles> Once upon a time I was embarrassed while checking coils for accuracy with an inspector from a client company sitting next to me, I had to re-tune every one I had tuned a couple of days before. WTF? I had no idea the plant manager rushed them through and meanwhile the tension had relaxed throwing them way out of whack until I asked the design engineer about my predicament and he explained it to me.
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Originally Posted by KG4CGC
