I agree totally with Bob about the dangers of running the GS-35B at
voltages above 3800 Volts. Though it has been done, it is a very risky
cloud to fly in and not where I would want to go. There are plenty of
tube failures attributed to running the voltage too high. Running Ep at
3800 will reduce the Ip, HF efficiency will be up a bit and drive will
be slightly less. All in all, very satisfactory for a hundred buck tube!
73, Tony W4ZT
w6ah@comcast.net wrote:
> 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@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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|