After reading a lot of information on the net and with a lot of input from friends after seeing these pictures there appears to be three possible explanations for the colorful glow.
The first resonable theory is electron bombardment causing trace elements in the ceramic mixture to fluoresce. This theory is suported by the fact that the glow dies away from the bottom of the tube as I reduce the plate current.
The second theory is that soft X-rays produced when the electrons strike the copper anode are striking the ceramic and causing it to glow. The one thing that troubles me about this is that fact that the glow dies away from the bottom of the tube and remains high on the shoulder of the tube which should be shielded from X-rays coming from inside the anode. Low level soft X-rays do not penetrate well and are not considered a danger to humans.
The third theory is that there may be some oxide migration from the cathode to the ceramic surface inside causing a glow.
The My current thinking is that different ceramic mixes, perhaps coming from different locations and containing different trace elements, are responsible for the different colors. I have documented colors including PURPLE, BLUE, LIGHT BLUE, WHITE, GREEN and ROSE/LAVENDER. Glowing tubes does NOT mean these tubes are bad! Perfectly good tubes glow beautifully!
Please share pictures of your glowing tubes with us. I will be happy to post your good pictures here. 73, Tony W4ZT
Please tell me the coil shown above the left tube is NOT the output tank coil.
Somebody needs to learn how to use the correct bolt lenghts too, yuk!
Please tell me the coil shown above the left tube is NOT the output tank coil. [/QUOT
No, those were early pics from when I was 'roughing it" in for the prupose of placement of parts. It was a substitute for the tuned input coil.
As far as screw length, those were 'Junk Box" parts and, once they were there, they became part of the amp; cosmetically ugly but, 100% functional. Just say it was a 'protptype'. In fact, each succeeding project is an upgrade of the previous project.
My next amp 'could' be a 80 thru 10 meter "Thing of beauty" that will be a single tube design.
.
Dunno, never had a DaveMade.That ain't no old ready for the land fill Davemade now is it? Can you say AWESOME?
Having more of a mechanical back ground than electrical, it stuck out at me. When I used to build sprint cars, no nut had more than a thread, or maybe two of the bolt sticking out.As far as screw length, those were 'Junk Box" parts and, once they were there, they became part of the amp; cosmetically ugly but, 100% functional. Just say it was a 'protptype'. In fact, each succeeding project is an upgrade of the previous project.
Please tell me the coil shown above the left tube is NOT the output tank coil. [/QUOT
No, those were early pics from when I was 'roughing it" in for the prupose of placement of parts. It was a substitute for the tuned input coil.
As far as screw length, those were 'Junk Box" parts and, once they were there, they became part of the amp; cosmetically ugly but, 100% functional. Just say it was a 'protptype'. In fact, each succeeding project is an upgrade of the previous project.
My next amp 'could' be a 80 thru 10 meter "Thing of beauty" that will be a single tube design.
.
Ya know what Paws I usually break your stones but your out there Homebrewing amps that are working. I say when you put the damn lid on it who cares what it looks like inside, all you gotta do is look at the watt meter.
:closedeyes:
Gee, I dunno, the person taking the lid off?I say when you put the damn lid on it who cares what it looks like inside, all you gotta do is look at the watt meter.
:closedeyes:
That ain't no old ready for the land fill Davemade now is it? Can you say AWESOME?