Homebrew breadboard xmtr
 

Nice work! Very nice!


exray wrote:
Hi,
I've gotten far enough along with this project to where I'm ready to
toss it out for public scrutiny, so have at me, guys.

I'm a receiver guy - never built a tube transmitter from scratch and
this is my first go. My goals were, in no particular order, to build
something with a early 30s breadboard look, xtal control, 40/20 meters
primarily - 80/30 as bonus, moderate power for getting on the air
barefoot while not overpowering a future amp idea...and of course using
accessible parts.

This is sort of my compilation of ideas from old QST articles. Robbed
ideas from this and that to make them fit. I made some major boo-boos
at first but I think I finally have them sorted out. Something that
dawned on me a little bit slowly is that none of those old xmtrs were
set up to operate 40 meters with a 7 Mc xtal. Much of the emphasis was
on double this/double that. Nowadays we have 7 and 14 Mc fundamental
xtals abounding so I went the route of reinventing the wheel so to speak.

The rig is working at this stage...at least straight thru on 40. Waiting
for some other bits and bobs to carry on to other bands. The note
sounds good and its nothing I'm reluctant to put on the air. On the
other hand its a massive amount of wood and metal for a measly 5 or 6
watts :) A little slatboard 6V6 chirper would have been much easier.

Anyway, I'm not a veteran with old xmtrs so I'm putting it out for
comments, questions, critiques, etc. Flame suit is handy!

Schematic:
http://i132.photobucket.com/albums/q...hema111108.jpg

View:
http://i132.photobucket.com/albums/q...r/Dscf1436.jpg


-Bill WX4A/KP4

Homebrew breadboard xmtr
 

Wow!

Superb indeed!
__
Gregg

Homebrew breadboard xmtr
 

geek wrote:
Wow!

Superb indeed!
__
Gregg

Thanks guys.
-Bill

Homebrew breadboard xmtr
 

exray wrote:
Hi,
I've gotten far enough along with this project to where I'm ready to
toss it out for public scrutiny, so have at me, guys.

I'm a receiver guy - never built a tube transmitter from scratch and
this is my first go. My goals were, in no particular order, to build
something with a early 30s breadboard look, xtal control, 40/20 meters
primarily - 80/30 as bonus, moderate power for getting on the air
barefoot while not overpowering a future amp idea...and of course using
accessible parts.

This is sort of my compilation of ideas from old QST articles. Robbed
ideas from this and that to make them fit. I made some major boo-boos
at first but I think I finally have them sorted out. Something that
dawned on me a little bit slowly is that none of those old xmtrs were
set up to operate 40 meters with a 7 Mc xtal. Much of the emphasis was
on double this/double that. Nowadays we have 7 and 14 Mc fundamental
xtals abounding so I went the route of reinventing the wheel so to speak.

The rig is working at this stage...at least straight thru on 40. Waiting
for some other bits and bobs to carry on to other bands. The note
sounds good and its nothing I'm reluctant to put on the air. On the
other hand its a massive amount of wood and metal for a measly 5 or 6
watts :) A little slatboard 6V6 chirper would have been much easier.

Anyway, I'm not a veteran with old xmtrs so I'm putting it out for
comments, questions, critiques, etc. Flame suit is handy!

Schematic:
http://i132.photobucket.com/albums/q...hema111108.jpg

View:
http://i132.photobucket.com/albums/q...r/Dscf1436.jpg


-Bill WX4A/KP4

Nothing that pretty can possibly work.

:-)

--

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

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Homebrew breadboard xmtr
 

On Nov 15, 2:10*pm, Tim Wescott wrote:
exray wrote:
Hi,
I've gotten far enough along with this project to where I'm ready to
toss it out for public scrutiny, so have at me, guys.

I'm a receiver guy - never built a tube transmitter from scratch and
this is my first go. *My goals were, in no particular order, to build
something with a early 30s breadboard look, xtal control, 40/20 meters
primarily - 80/30 as bonus, moderate power for getting on the air
barefoot while not overpowering a future amp idea...and of course using
accessible parts.

This is sort of my compilation of ideas from old QST articles. *Robbed
ideas from this and that to make them fit. *I made some major boo-boos
at first but I think I finally have them sorted out. *Something that
dawned on me a little bit slowly is that none of those old xmtrs were
set up to operate 40 meters with a 7 Mc xtal. *Much of the emphasis was
on double this/double that. *Nowadays we have 7 and 14 Mc fundamental
xtals abounding so I went the route of reinventing the wheel so to speak.

The rig is working at this stage...at least straight thru on 40. Waiting
for some other bits and bobs to carry on to other bands. *The note
sounds good and its nothing I'm reluctant to put on the air. *On the
other hand its a massive amount of wood and metal for a measly 5 or 6
watts :) *A little slatboard 6V6 chirper would have been much easier.

Anyway, I'm not a veteran with old xmtrs so I'm putting it out for
comments, questions, critiques, etc. *Flame suit is handy!

Schematic:
http://i132.photobucket.com/albums/q...r/schema111108...

View:
http://i132.photobucket.com/albums/q...r/Dscf1436.jpg

-Bill WX4A/KP4

Nothing that pretty can possibly work.

:-)

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

Looks like something I found in my grandfather's car house. His was a
wood frame with copper sheeting. He said he built it a few years
before WWII. We cleaned it up and he fired it up and he lit up a
little light bulb so I'm figuring 3 or 4 watts. After that I polished
up the copper and really cleaned it up and fired it up one more time.
He ran a depot for the railroad and was always going to get his ham
ticket but never did though he knew morse code extremely well and
built several transmitters and receivers.


Jimmie

Homebrew breadboard xmtr
 

JIMMIE wrote:

On Nov 15, 2:10 pm, Tim Wescott wrote:

exray wrote:

Hi,
I've gotten far enough along with this project to where I'm ready to
toss it out for public scrutiny, so have at me, guys.

I'm a receiver guy - never built a tube transmitter from scratch and
this is my first go. My goals were, in no particular order, to build
something with a early 30s breadboard look, xtal control, 40/20 meters
primarily - 80/30 as bonus, moderate power for getting on the air
barefoot while not overpowering a future amp idea...and of course using
accessible parts.

This is sort of my compilation of ideas from old QST articles. Robbed
ideas from this and that to make them fit. I made some major boo-boos
at first but I think I finally have them sorted out. Something that
dawned on me a little bit slowly is that none of those old xmtrs were
set up to operate 40 meters with a 7 Mc xtal. Much of the emphasis was
on double this/double that. Nowadays we have 7 and 14 Mc fundamental
xtals abounding so I went the route of reinventing the wheel so to speak.

The rig is working at this stage...at least straight thru on 40. Waiting
for some other bits and bobs to carry on to other bands. The note
sounds good and its nothing I'm reluctant to put on the air. On the
other hand its a massive amount of wood and metal for a measly 5 or 6
watts :) A little slatboard 6V6 chirper would have been much easier.

Anyway, I'm not a veteran with old xmtrs so I'm putting it out for
comments, questions, critiques, etc. Flame suit is handy!

Schematic:
http://i132.photobucket.com/albums/q...r/schema111108...

View:
http://i132.photobucket.com/albums/q...r/Dscf1436.jpg

-Bill WX4A/KP4

Nothing that pretty can possibly work.

:-)

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -


Looks like something I found in my grandfather's car house. His was a
wood frame with copper sheeting. He said he built it a few years
before WWII. We cleaned it up and he fired it up and he lit up a
little light bulb so I'm figuring 3 or 4 watts. After that I polished
up the copper and really cleaned it up and fired it up one more time.
He ran a depot for the railroad and was always going to get his ham
ticket but never did though he knew morse code extremely well and
built several transmitters and receivers.


Jimmie
Very Nice Tim OM!
A few years back I built an 80M rig from a 1928 QST design.
A bit bigger than that basically a T20 triode driving (I think)a 100TH
Colpitts oscillator and power amplifier. It worked surprisingly well,
put out about 60 watts and to mysurprise was much more stable that I
expected given a VFO putting out about 7 watts of RF!!!
Had few QSO's with it and then had to dispose of it when I retired and
moved house. I hope my fellow NZ Vintage radio club member is looking
after it! Of course they can be a bit lethal mine had 1Kv ht and apart
from an insulated front panel it was all accessible.
73 Cliff Wright ZL1BDA ex G3NIA

Homebrew breadboard xmtr
 

Hi, Bill.
Indeed it is a great looking project.

I don't see anyone attempting to answer you question about why the
early transmitters always doubled or tripled from stage to stage. As I
recall, this was used to minimize the loading on previous stages as a
subsequent stage was tuned. The loading caused frequency changes. This
was used only on triode tubes. When screen grid stages were used, it
was no longer necessary.

Further research would have shown 160 meter crystals were frequently
used to control 80 meter transmitters. It wasn't just because the
higher frequency crystals were not available. They were just more
expensive.

Again, a great looking project. I do see a modern resister in there,
however.

73's, Paul, KD7HB


On Nov 11, 8:35*pm, exray wrote:
Hi,
I've gotten far enough along with this project to where I'm ready to
toss it out for public scrutiny, so have at me, guys.

I'm a receiver guy - never built a tube transmitter from scratch and
this is my first go. *My goals were, in no particular order, to build
something with a early 30s breadboard look, xtal control, 40/20 meters
primarily - 80/30 as bonus, moderate power for getting on the air
barefoot while not overpowering a future amp idea...and of course using
accessible parts.

This is sort of my compilation of ideas from old QST articles. *Robbed
ideas from this and that to make them fit. *I made some major boo-boos
at first but I think I finally have them sorted out. *Something that
dawned on me a little bit slowly is that none of those old xmtrs were
set up to operate 40 meters with a 7 Mc xtal. *Much of the emphasis was
on double this/double that. *Nowadays we have 7 and 14 Mc fundamental
xtals abounding so I went the route of reinventing the wheel so to speak.

The rig is working at this stage...at least straight thru on 40.
Waiting for some other bits and bobs to carry on to other bands. *The
note sounds good and its nothing I'm reluctant to put on the air. *On
the other hand its a massive amount of wood and metal for a measly 5 or
6 watts :) *A little slatboard 6V6 chirper would have been much easier.

Anyway, I'm not a veteran with old xmtrs so I'm putting it out for
comments, questions, critiques, etc. *Flame suit is handy!

Schematic:http://i132.photobucket.com/albums/q...r/schema111108...

View:http://i132.photobucket.com/albums/q...r/Dscf1436.jpg

-Bill WX4A/KP4

Homebrew breadboard xmtr