Tech Notes from the Field

I had the pleasure of a visit from Mr. Geoffery Mendenhall of Harris Corp. the other day. We had a nice lunch and chat. We even visited the transmitter site to discuss the tube and life of these beasts in the HD world.

I have submitted the tube to Econco for an evaluation on how this tube fared. I will keep you posted on this. Our conversation focused on the fact that the failing tube caused IPA overloads. As the filament carbonizes we see a higher resistance and need more power to maintain emissions. Also we are thinking there is some increase in reactance withing the grid circuit. Somewhere a point is attained where the IPA cannot provide the necessary drive and overloads.

Once we have some evaluation on the state of the tube after removal we will not really know how far along or “burned out” the thing is. As the digital carriers require higher peak current, this tube in an analog transmitter would probably last a bit longer. All very interesting things.

Stay tuned for any other information that I may come across.