[AMPS] professional glass blowers

[Ian White, G3SEK]

Carl wrote:

G3SEK wrote:
>>FWIW, I've been using Pyrex glass chimneys with 4CX250Bs for well 
>>over
>>20 years. They were cut from stock tubing that was a close slip fit 
>>over
>>the anodes, the ends ground square, and simply glued on to the base 
>>with
>>silicone rubber. Works fine.

>
>
>There is a big requirement difference between tiny little tetrodes and
>large glass tubes and then going up to the 8877 and above level.
>
That's what "FWIW" meant: "for what it's worth", i.e. whatever comes
after may not apply in all cases.

>Too often hams do not understand the air requirements of their particular
>choice and are mesmerised by misinformation and pure BS.  Please also
>understand that in many cases the published air requirements are for CCS
>AM duty. 
>
Slight change of subject here?

>Pyrex at the hard working 4-1000A level is a poor choice...period.

So what material do/should they use for chimbleys for 4-1000As... or do
you suggest not using a chimney and blowing across the tube?

> With a
>4CX250B almost anything will work., even a fruit jar.

>I try to keep things simple in my replies and reference common interests
>and power levels; not useless 200KW tales and CB level amps. Those who
>have a problem with that already know my answer.

With a 4CX-anything, it had better be a fruit jar of exactly the right
internal diameter, or else the air will bypass the finned cooler.

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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