Homebrew breadboard xmtr
 

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
 

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

Looks SUPER COOL! How's the harmonics? Did you use any external low
pass filter? Spectrum analyzer trace available?

Keep playing with it! Looks like a neat little project!

Scott
N0EDV

Homebrew breadboard xmtr
 

Scott wrote:


Looks SUPER COOL! How's the harmonics? Did you use any external low
pass filter? Spectrum analyzer trace available?

Thanks. No I can't answer any of the harmonic issues. My closest
neighbor is still an antenna-bound tv viewer and she doesn't report any
interference...which was on my list of goals as well. It has been a
limiting factor in the past.
-Bill

Homebrew breadboard xmtr
 

exray wrote:

snip

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

snip

Beautiful! Would you consider a breadboarded arc or spark xmitter
for your next project? Some years ago I did one using the obligatory
Model T spark coil, on 80m, that lit up a 12W bulb dummy load quite
brightly.

Michael

Homebrew breadboard xmtr
 

msg wrote:
exray wrote:

snip

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

snip

Beautiful! Would you consider a breadboarded arc or spark xmitter
for your next project? Some years ago I did one using the obligatory
Model T spark coil, on 80m, that lit up a 12W bulb dummy load quite
brightly.

Michael

Hehe, I don't think they would allow me on the air with that :)

-Bill

Homebrew breadboard xmtr
 

Looks good, no, very good. Better than my home made transmitters.

On the schematic, you missed a strap on the doubler coil. The ground pin
should be connected to the nearby "coil" pin. I didn't go over the
schematic in detail but I was interested in how you connected the
doubler coil.

Bill K7NOM
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
 

Bill Janssen wrote:
Looks good, no, very good. Better than my home made transmitters.

On the schematic, you missed a strap on the doubler coil. The ground pin
should be connected to the nearby "coil" pin. I didn't go over the
schematic in detail but I was interested in how you connected the
doubler coil.

Bill K7NOM

Good eye. I'll make the correction on the drawing. Thanks.

Bill WX4A

Homebrew breadboard xmtr
 

exray wrote:

Bill Janssen wrote:

Looks good, no, very good. Better than my home made transmitters.

On the schematic, you missed a strap on the doubler coil. The ground
pin should be connected to the nearby "coil" pin. I didn't go over the
schematic in detail but I was interested in how you connected the
doubler coil.

Bill K7NOM


Good eye. I'll make the correction on the drawing. Thanks.

Bill WX4A

Just a matter of taste of course, but I find that using dots on wire
connects, even with the use of arced cross-overs, improves readability ;)

Michael

Homebrew breadboard xmtr
 

msg wrote:


Just a matter of taste of course, but I find that using dots on wire
connects, even with the use of arced cross-overs, improves readability ;)

Michael


Ok, dots-r-us. Revised.

Bill

Homebrew breadboard xmtr
 

Super job, Bill!!
Who cares if it only does a couple of watts, it's beautiful!! I have a
replica 1933 TPTG transmitter that is surface mount, wood base. (built by
another ham--nice job as well).

73. Russ W6OHM

"exray" wrote in message
...
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