[R-390] Ballast Tube Thread

[Bob Camp]

Hi

Well we had  been heading for the record in the "longest most inane 
ballast tube thread not mentioning solid state solutions". Now I think 
we will have to go for the longest most inane ballast tube thread - 
unlimited category.

I would suggest at least two PIC processors with some nice long high 
speed leads. We could put one part in the ballast tube socket and run 
the wires through the IF chassis and in to the RF chassis. If we get 
enough stuff running back and forth an R-390 can work just like a rice 
box.

The standard solid state solution for years was to put in a full wave 
bridge rectifier and with a low voltage linear regulator set up as a 
constant current source on the inside.  The normal problem is that the 
current moves through in in pulses rather than as continuos AC. The 
pulses generate RFI. Since you are in the middle of the radio that's 
not a good idea.

A more interesting approach might be to use a couple of mosfet's and 
rig them so they do pass AC. It would be a lot more circuitry though.

The final problem you run into is that you have to get rid of 5 watts 
from a solid state device. You don't need a monster heat sink but you 
won't get away with out some kind of heat sink.

Now, with a fairly small tank of liquid nitrogen we could get around 
the cooling problem. There would be some minor plumbing issues but it 
should work. The Air Products truck could drop by from time to time to 
keep you topped up.

	Take Care

		Bob Camp
		KB8TQ



On Jul 5, 2004, at 11:34 PM, Lee Bahr wrote:

> What about a "lively" discussion on building "adapter" sockets for 
> lesser
> used 29 cent Ballast Tubes?  We could include blinking LEDs around the
> perimeter of the adapter socket for enhanced desirability.
>
> What do you guys think?  Should the LEDs be white, blue, red, yellow or
> orange?  Super Brite or what?
>
> Or, we could include a transducer to emit eerie R-390A sounds as the 
> ballast
> did it's thing!
>
> Or, we could include a micro memory keyer to constantly send the 
> R-390A's
> serial number if it were ever stolen.
>
> Or, it could give a beeping sound with greater intensity when line 
> voltage
> was dropping or rising to an dangerous level!
>
> What do you guys think?
>
> Lee, w0vt
>
> PS:  (Side note) What type of solder should we all be using?  And, can 
> I
> reuse black beauties if I epoxy the cracked cases shut?
>
>
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