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

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

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

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 -- Svetlana USA is not owned by the
company that owns the Svetlana factory, and they've had a falling out.
The Svetlana factory in Russia now markets their tubes as "circle C"
(the Tubes Formerly Known As Svetlana?), but all the nifty articles
aren't accessible.

The ARRL makes sure to include a few linear projects in each handbook,
so there's plenty of choices. I'd make concrete suggestions, but 5
watts is QRO for me.

--

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

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 -- Svetlana USA is not owned by the
company that owns the Svetlana factory, and they've had a falling out.
The Svetlana factory in Russia now markets their tubes as "circle C"
(the Tubes Formerly Known As Svetlana?), but all the nifty articles
aren't accessible.

The ARRL makes sure to include a few linear projects in each handbook,
so there's plenty of choices. I'd make concrete suggestions, but 5
watts is QRO for me.

--

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

Depends on how much bragging you plan on doing about your amp. Some folks
wouldn't be caught dead with anything less than a pair of 8877's, just to keep
ahead of their peers. "I tell you what ... I can run full legal limit with
only 1/2 watt drive". Personally, I have run a pair of 3-500's for years
without any undo strain on the components. Look at the photo's of the "big gun"
DX multi-ops ... W3LPL, K0RF, and the like, many run some beat up, homebrew,
single band amp running a pair of 3-500z's, to 6/6/6 at 200 ft. So you see
where their money goes.

Plus, have you looked at the cost of tubes lately?

Check out the contesting.com (I beleive) archives of the [AMPS] email list.
That should provide hours of reading towards your project.

GOOD LUCK!

jw
K9RZZ

Depends on how much bragging you plan on doing about your amp. Some folks
wouldn't be caught dead with anything less than a pair of 8877's, just to keep
ahead of their peers. "I tell you what ... I can run full legal limit with
only 1/2 watt drive". Personally, I have run a pair of 3-500's for years
without any undo strain on the components. Look at the photo's of the "big gun"
DX multi-ops ... W3LPL, K0RF, and the like, many run some beat up, homebrew,
single band amp running a pair of 3-500z's, to 6/6/6 at 200 ft. So you see
where their money goes.

Plus, have you looked at the cost of tubes lately?

Check out the contesting.com (I beleive) archives of the [AMPS] email list.
That should provide hours of reading towards your project.

GOOD LUCK!

jw
K9RZZ

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

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca

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

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca

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