[Amps] Building or Buying a Tuned Input Network

w6ah@comcast.net w6ah at comcast.net
Mon Jan 23 01:48:45 EST 2006


Drive power relates to output indirectly as anode voltage, biasing and operating frequency all influence output power. With 3000 volts on the plate OZ1DPR obtained the following

10 watts drive,  400 mils of plate current, 300 watts out
50 watts drive,  700 mils of plate current, 800 watts out
100 watts drive,  950 mils of plate current, 1550 watts out

The above figures are for 6 meters with a biasing of 30 volts. Though the recommended plate voltage is 3000 volts the tube has a pulse rating of 6000 volts. Many hams are running them at higher voltages some as high as 4500 volts. From what I can deduce from annecdotal data running this tube beyond 3800 volts increases the risk of arc-over, with resultant grid damage, substantially.

Running this tube on HF should yield an increase of 5 to 10 perent in efficiency from the numbers stated above.

73s

Bob W6AH

-------------- Original message -------------- 
From: Bill Turner <dezrat1242 at ispwest.com> 

> ORIGINAL MESSAGE: 
> 
> At 09:14 PM 1/22/2006, Tony King - W4ZT wrote: 
> 
> >I hand made a board of my own (had my own nice 5 amp contact DPDT 
> >relays, Arco trimmers and cores and did essentially the same thing 
> >but I did leave larger pads to allow for the trimmers 
> >. 
> 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
> 
> Boy are you thorough! Nice work. 
> 
> Changing the topic slightly, how much drive does a GS-35b need for 
> 1500 watts output? It's probably on the web somewhere but I've looked 
> and can't find it. The comparison chart between it and the 8877 shows 
> a ~2dB difference in gain but no actual drive numbers. I could figure 
> it in reverse but I'd like to hear from someone with actual experience. 
> 
> 73, Bill W6WRT 
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