233D Transmitter Restoration Project
Larry has found the routing for the cabling to the roof, so after he finds some more coax, we should be able to get some sort of antenna up and see what the receive noise is like.
He also starting on the super deluxe power â€ścartâ€ť for the plate transformer and contactor panel. I have cut away all the cable lacing in the contactor panel and am making some headway on understanding the as wired vs. schematic differences. Still a little curious about the method being used to drop the 3 phase input during â€śTestâ€ť mode. Could use some help with that aspect. Otherwise, Iâ€™ll just apply power and stand back.
Quality Plating has finished the chrome plating and we should have them back by next week.
Ralph, the helpful security guard is retiring on July 25th, so we need to make sure his replacement understands what we need with regard to taking equipment in and out, although most of that part is pretty much complete. He also said that on October 1, the SW 120 entranced will no longer be manned during the standard business day. He said only for 2 hours although I am not certain if that varies or is at certain times. Hope we can make arrangements to sign in visitors during Museum hours on Wednesday. My badge does not allow me to access the building unless a guard is present, so Iâ€™ll need to get that changed or maybe by October first, the project will be pretty much wrapped and I wonâ€™t need access.
I saw Mark Hovda on Wednesday and he suggested we consider using RC experimental HF licenses to get on the air with full output. We will need to determine if AM and CW are allowed modes on any of the licenses, but Mark thinks that anything goes with those licenses. Randy Nelson was maintaining those permits, so I will try to talk to him next week to see if that works. Iâ€™m assuming that the ART-13 in Fifi could get on one of those frequencies. Still want to get the transmitter on some of the AM ham band frequencies. But we need to address how we will get the power done to somewhat close to legal. Test mode should drop the plate voltage down to about 2100 volts, but I donâ€™t know how that will work out with the modulator. The 813s in the exciter should be capable of about 500 watts, so maybe we can work with that.
We are still short wirewound resistors in the HV bleeder network, so we may need to do some work to adapt available parts. Still looking for the mica in the PA grid network, but we can use doorknobs for that if we need.
Next week is the kickoff for the rebuild phase. Lets all try to get together next week on Wednesday during museum opening hours.
| July 12, 2013