233D Transmitter Restoration Project
Larry is fabâ€™ing a roll around mount for the plate transformer and contactor; that should make things better with regard to checking things out and should add considerably to the visual aspect of the transmitter.
He also found an entry to the roof and has tentatively got authorization to install at least a temporary antenna. He thinks we should get something up and hook up a receiver to determine what the noise environment will be like. He also talked to the folks that installed a temporary antenna when the trash truck took out all the feedlines a few years back and thinks that the feedline to that antenna location is still coming into the overhead but the outside end is buried where the temporary antenna was installed, so that may be somewhat of a challenge but is certainly an alternate approach, if the roof antenna proves unacceptable.
I expect that the plating on the chassis at Sterling should be complete by the end of next week. So we should have the chassis here in Cedar the week ending July 19. Iâ€™ll do the modulator tube chassis since Iâ€™ve torn it down twice and it should only take about 30 minutes to put it back together. But the bias supply and the HV rectifier will be challenges and it would be great to have some help with those. I have lots of images, so we shouldnâ€™t have much problem putting them back together.
We have not been successful in finding the large wire-wound resistors for the HV bleeder and HV voltmeter networks, so we will have to consider an alternate approach using more readily available parts. We are also still missing the HV mica on the PA grid network.
Rod is continuing to raise the standard with the exciter chassis; I expect it will look as good as the output network. When he finishes with exciter, we will be able to get to work on the Autotune system. I still need to determine what frequencies we will use so we can get crystals on order. For testing, we may want to use one of the HF-80 exciters to get the exciter tuned up.
Phil Legate responds...
With regard to the antenna system, you might contact Jack Colon. I designed an antenna system for the Bldg 106 rigs that was flat out to about 23 Mhz using an S9 vertical and a tapped loading coil. Jack had it installed according to my design.
| July 5, 2013