21-03-2017, 02:20 AM
Something I hadn’t noticed until recently revisiting this thread was that the T99 had a four-gang tuning capacitor. Did it have two tuned RF stages? Or was there bandpass tuning, either at the input or the interstage?
The preceding T69 I think had a three-gang capacitor, but using just three bays of a four-bay capacitor frame, rather as Eddystone did with some of its models.
The following T139 had a three large + three small gang capacitor, the smaller unit being used for bandpsread. In this case Dynatron may have been limited by unit availability, and had to settle for three main gangs even though it might have wanted four. The “3+3” form was fairly standard, but “4 + 4” was probably rare. Although with bandpsread, sometimes fewer gangs were used than for the wide-coverage bands, with fixed bandpass couplings around 0.5 MHz wide in their place. (For example, Murphy did this with its TA160, and Philips with its 681A.)
Cheers,
Steve
The preceding T69 I think had a three-gang capacitor, but using just three bays of a four-bay capacitor frame, rather as Eddystone did with some of its models.
The following T139 had a three large + three small gang capacitor, the smaller unit being used for bandpsread. In this case Dynatron may have been limited by unit availability, and had to settle for three main gangs even though it might have wanted four. The “3+3” form was fairly standard, but “4 + 4” was probably rare. Although with bandpsread, sometimes fewer gangs were used than for the wide-coverage bands, with fixed bandpass couplings around 0.5 MHz wide in their place. (For example, Murphy did this with its TA160, and Philips with its 681A.)
Cheers,
Steve
