[Milsurplus] Query

[David Edsall]

Who said anything about an envelope?
(below)
D.

----- Original Message ----- 
From: <jfor at quik.com>
To: "David Edsall" <dedsall at crocker.com>
Cc: <milsurplus at mailman.qth.net>
Sent: Wednesday, March 12, 2008 10:51 AM
Subject: Re: [Milsurplus] Query


> Of course you could. The heat loss from a filament is by conduction
> through the leads, which would be unchanged, convection, which is
> essentially zero, and radiation. The only material influence would be the
> loss of heat to the filament from radiation back to the filament from the
> envelope, and that's essentially trivial.
>
> -John
>
>
>
>
>> Hi Pete, Jim and all,
>>
>> Yes, interesting thought, operating a vacuum tube in the vacuum of space.
>> But consider the temperature in space and what it would do to the
>> elements.
>> Could you even light the filament?
>> Now that's a cold 807!
>> 73, David W1TDD
>>
>> ----- Original Message -----
>> From: "Jim Haynes" <jhhaynes at earthlink.net>
>> To: "Pete Williams" <jupete at bigpond.net.au>
>> Cc: <milsurplus at mailman.qth.net>
>> Sent: Tuesday, March 11, 2008 10:58 PM
>> Subject: Re: [Milsurplus] Query
>>
>>
>>>I don't know the answer, but that reminded me that back in my student
>>> days some 50 years ago, when the Space Age was just starting, we used
>>> to imagine you could operate vacuum tubes in space without any glass
>>> bulb.
>
>
>