Gregg wrote:
Behold, Tim Wescott signalled from keyed 4-1000A filament:


Highland Ham wrote:


In your opinion, which commonly available tubes sound appropriate? I'm
particularly interested in hearing from hams that have built units with
similar DC supplies.

This is likely to be a long term project, with minimum amount of time
to work on it at a time, and likely extensive amounts of time to find
appropriate components at a reasonable cost (think beer budget and
champagne dreams)..

========================================== If second hand tubes are not
considered I suggest to have a look at the Svetlana web site. If valves
can provide the wanted power at 29 MHz ,they certainly can do at 1.8
MHz.

If Eimac or similar tubes are available like the 3-500Z , 2 of
those in parallel are fine and so is a single 8877 or 3CX1500

Ref ARRL Handbook 1995 (and probably others) ,chapter 13

Good Luck with your project

Frank GM0CSZ / KN6WH






Alas, the Svetlana site has expired


Not if you know where to look ;-)

http://www.svetlana.com/docs/tubeframe.html


How cool. There has to be some kind of saga behind this whole Svetlana
business.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

You'll save time and money by getting a used Heathkit SB-220 for about
$500.00 or less and add 160 to it, or a Drake L-7 about $700.00 or more..
Both use two 3-500Z and are well engineered linears. And after you're tired
of it you can get most of your money back. Even if you put time in effort
in you'll get very little back. So get a 220 or L-7 and start collecting
parts for your dream when you find them cheap. JMHO

--
73
Hank WD5JFR
"Rick Frazier" wrote in message
...
I'm thinking about building an HF linear, primarily for SSB use, and am
having difficulty in choosing an appropriate tube (or tubes).

I want to be able to get full legal output (U.S.A.) with input of 55-65
watts max, so as to not tax an Icom 751a or 746Pro which would be
driving. I'd prefer to be able to get to 160m, but could probably live
with 20-10m if I had to. I want something that can "loaf along" without
strain to prevent overtaxing components.

I may have access to a transformer that can provide 2100-2300 volts AC
at several amperes, so I suppose I'm looking for a tube (or tubes) that
can work with 2800 to 3300 VDC on the plate(s). (At the high end, it
may be possible to provide 3200 volts and as much as 5 amperes of
current... so at legal limits, the HV power supply should be able to
keep up with little or no voltage sag.) Of course, something capable
of high power output that can run along at way less than full output is
preferred to another that has to run at the ragged edge to provide the
same output. (It goes without saying that close monitoring is required
to make sure the legal limits aren't exceeded, but that should be part
of good operating practice anyway, IMHO.)

In your opinion, which commonly available tubes sound appropriate? I'm
particularly interested in hearing from hams that have built units with
similar DC supplies.

This is likely to be a long term project, with minimum amount of time to
work on it at a time, and likely extensive amounts of time to find
appropriate components at a reasonable cost (think beer budget and
champagne dreams)..

Thanks
Rick AH7H

You'll save time and money by getting a used Heathkit SB-220 for about
$500.00 or less and add 160 to it, or a Drake L-7 about $700.00 or more..
Both use two 3-500Z and are well engineered linears. And after you're tired
of it you can get most of your money back. Even if you put time in effort
in you'll get very little back. So get a 220 or L-7 and start collecting
parts for your dream when you find them cheap. JMHO

--
73
Hank WD5JFR
"Rick Frazier" wrote in message
...
I'm thinking about building an HF linear, primarily for SSB use, and am
having difficulty in choosing an appropriate tube (or tubes).

I want to be able to get full legal output (U.S.A.) with input of 55-65
watts max, so as to not tax an Icom 751a or 746Pro which would be
driving. I'd prefer to be able to get to 160m, but could probably live
with 20-10m if I had to. I want something that can "loaf along" without
strain to prevent overtaxing components.

I may have access to a transformer that can provide 2100-2300 volts AC
at several amperes, so I suppose I'm looking for a tube (or tubes) that
can work with 2800 to 3300 VDC on the plate(s). (At the high end, it
may be possible to provide 3200 volts and as much as 5 amperes of
current... so at legal limits, the HV power supply should be able to
keep up with little or no voltage sag.) Of course, something capable
of high power output that can run along at way less than full output is
preferred to another that has to run at the ragged edge to provide the
same output. (It goes without saying that close monitoring is required
to make sure the legal limits aren't exceeded, but that should be part
of good operating practice anyway, IMHO.)

In your opinion, which commonly available tubes sound appropriate? I'm
particularly interested in hearing from hams that have built units with
similar DC supplies.

This is likely to be a long term project, with minimum amount of time to
work on it at a time, and likely extensive amounts of time to find
appropriate components at a reasonable cost (think beer budget and
champagne dreams)..

Thanks
Rick AH7H