[Amps] 4CX5000A in grounded-grid

[Peter Voelpel]

Hi Ron, 

The main air flow is through the anode by the large blower.
That is quite common with VHF/UHF amplifiers in Europe.
The cathode area is cooled by that separate fan. Of course the amp is
mounted with the tube vertical.

Cooling through the anode and use of a bypass duct to the cathode area is
quite common in Europe.
Almost every commercial VHF/UHF amp is constructed like that.

73
Peter


-----Original Message-----
From: KA4INM [mailto:ka4inm at gmail.com] 
Sent: Dienstag, 18. März 2014 14:52
To: Peter Voelpel
Subject: Re: [Amps] 4CX5000A in grounded-grid

   Hi  Peter DJ7WW Voelpel:

> That 2m amplifier is not run zero bias but with normal screen and grid
voltages for AB1.
> Power gain is about 13db.
> I know the builder quit well.
> You see more photos on his web site:

> http://www.dj5dm.de/DJ5DM%20R17%20QRP%20Tube/index.htm

   Does he operate it with the blower on top or with the blower on the 
bottom?
This is the first time I ever saw a tube being blown from the top.  Very 
unusual construction.
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.