Maybe yours was the mystery circuit. Did yours have only one 6L6 and nothing
else, I mean no power supply rectifier? This rig does not even have a diode or
selenium under the hood, how can they do that? Do I have AC for the B+? I am
not an EE. What am I missing here? What mysteries lurk in the 6L6 that we
mortals do not fathom? Beam me up.

Bill / K6TAJ

garigue wrote:

Anyone seen a circuit for a singl 6L6 rig?...who
knows maybe it has the wrong tube in there. Hmmmm....how to do the
detective work on this????

Zeno ...sound like the one I built in 65 from the ham section in PE mag. I
tried to get someone to answer my CQs for 2 weeks with no reply ...then I
got a guy about 5 miles away...success then I got a card from an OO in
Oregon. I was proud of that card ...showed everyone what my 6L6 would do.

God Bless and Merry Christmas .... KI3R Tom Popovic Belle Vernon Pa.

Bill,
It sounds like you've been around awhile and have built some stuff in the
past.
Surely you can look at the circuit and figure out what is powering the
thing. Put your
meter into that thing and start measuring voltages (from the line cord,
through the transformer and on...)
Of course, if you find "any" DC - you've got a diode someplace. Take some
paper and draw out the schematic (can't be to hard for one tube circuit).
That
will show you what you have. Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have a
tube which sports a rectifier (diode section) and another tube in the same
envelope). At any rate - a part by part inspection resulting in a schematic
will tell all!
It's rather elementary. I'd be interested to hear what you find.
Good luck,
Roger, KL7Q

zeno wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a
single 6L6. Mostly made from radio and audio junkbox parts, it does
seem to work. I put it on the air briefly with its 40 meter Xtal and
monitored the signal on another antenna. Sounds kind of chirpy,
actually worse than chirpy. Needs some kind of work or upgrade or
correction. I did some web searching but could not actually come up
with a schematic for this rig, probably out of some old magazine or
something. I do not quite understand how it works without a power
supply rectifier. There is nothing under the hood which looks like a
diode or selenium rectifier. Anyone have a clue as to this circuit. I
am kind of new to this. How might I proceed to make this little rig
into a useable QRP unit. I think it probably makes something under 10
watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old
nice lay out failure, but it would be a fun challenge to convert it
into something useful. Anyone seen a circuit for a singl 6L6 rig?...who
knows maybe it has the wrong tube in there. Hmmmm....how to do the
detective work on this????

I have a certain nostalgia for simple one tube rigs, when I was a
novice in the early 50s as a kid I built this crazy rig with a single
117N7 that worked great with my very compromised end-fed random wire. I
have recently found the schematic for that one, but it seems kind of
crazy to build that one again, but who knows....the schematic for the
117N7 rig can be found on page 38 of "Radio For The Millions", 1945
Popular Science Publishing Co. Inc. This illustration has the chassis
plugged into the AC neutral/gound side. Another variation appears on
page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which
looks even more scarry since you only plug into the hot leg of the AC
outlet, and then ground the chassis to earth ground. I do not know how
I lived to tell you now that it was my first rig!

There is a one-tube rig on page 99 of "Ham Projects..." which uses a
6AV5 but that is not
the circuit I see in this unkown 6L6 rig. Let me know if you know of a
source for this single 6L6 transmitter. Nothing in either of the books
mentioned has one like this.

Other clues: it has three rf (air core) chokes, no other iron core
choke, uses two variable condensers, keys thru one of these chokes to
pin 8. Another choke goes from the antenna center pin to the chassis
ground. The 3 rf chokes used appear to be identical.

Bill / K6TAJ

Bill,
It sounds like you've been around awhile and have built some stuff in the
past.
Surely you can look at the circuit and figure out what is powering the
thing. Put your
meter into that thing and start measuring voltages (from the line cord,
through the transformer and on...)
Of course, if you find "any" DC - you've got a diode someplace. Take some
paper and draw out the schematic (can't be to hard for one tube circuit).
That
will show you what you have. Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have a
tube which sports a rectifier (diode section) and another tube in the same
envelope). At any rate - a part by part inspection resulting in a schematic
will tell all!
It's rather elementary. I'd be interested to hear what you find.
Good luck,
Roger, KL7Q

zeno wrote in message ...
I came across a cute little homebrew CW transmitter utilizing only a
single 6L6. Mostly made from radio and audio junkbox parts, it does
seem to work. I put it on the air briefly with its 40 meter Xtal and
monitored the signal on another antenna. Sounds kind of chirpy,
actually worse than chirpy. Needs some kind of work or upgrade or
correction. I did some web searching but could not actually come up
with a schematic for this rig, probably out of some old magazine or
something. I do not quite understand how it works without a power
supply rectifier. There is nothing under the hood which looks like a
diode or selenium rectifier. Anyone have a clue as to this circuit. I
am kind of new to this. How might I proceed to make this little rig
into a useable QRP unit. I think it probably makes something under 10
watts, and the cw sounds goofy, wimpy, and wobbly. It is someone's old
nice lay out failure, but it would be a fun challenge to convert it
into something useful. Anyone seen a circuit for a singl 6L6 rig?...who
knows maybe it has the wrong tube in there. Hmmmm....how to do the
detective work on this????

I have a certain nostalgia for simple one tube rigs, when I was a
novice in the early 50s as a kid I built this crazy rig with a single
117N7 that worked great with my very compromised end-fed random wire. I
have recently found the schematic for that one, but it seems kind of
crazy to build that one again, but who knows....the schematic for the
117N7 rig can be found on page 38 of "Radio For The Millions", 1945
Popular Science Publishing Co. Inc. This illustration has the chassis
plugged into the AC neutral/gound side. Another variation appears on
page 105 in "Ham Radio Projects" 1968 by Bert Simon, a circuit which
looks even more scarry since you only plug into the hot leg of the AC
outlet, and then ground the chassis to earth ground. I do not know how
I lived to tell you now that it was my first rig!

There is a one-tube rig on page 99 of "Ham Projects..." which uses a
6AV5 but that is not
the circuit I see in this unkown 6L6 rig. Let me know if you know of a
source for this single 6L6 transmitter. Nothing in either of the books
mentioned has one like this.

Other clues: it has three rf (air core) chokes, no other iron core
choke, uses two variable condensers, keys thru one of these chokes to
pin 8. Another choke goes from the antenna center pin to the chassis
ground. The 3 rf chokes used appear to be identical.

Bill / K6TAJ

"Roger and Ute Brown" ) writes:

Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have a
tube which sports a rectifier (diode section) and another tube in the same
envelope). At any rate - a part by part inspection resulting in a schematic
will tell all!

I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

I don't think the original poster mentioned if there was a transformer, and
somehow I suspect the lack of one would be a greater indicator of this route.

Of course, selenium recitifiers may have had a brief enough life that
someone might not recognize one by sight.

Michael VE2BVW

"Roger and Ute Brown" ) writes:

Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have a
tube which sports a rectifier (diode section) and another tube in the same
envelope). At any rate - a part by part inspection resulting in a schematic
will tell all!

I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

I don't think the original poster mentioned if there was a transformer, and
somehow I suspect the lack of one would be a greater indicator of this route.

Of course, selenium recitifiers may have had a brief enough life that
someone might not recognize one by sight.

Michael VE2BVW

Michael Black wrote:



I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

The 117L7 has a built-in diode section. Here's an xmtr made with one.
http://antiqueradio.org/lil7.htm

-Bill

Michael Black wrote:



I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

The 117L7 has a built-in diode section. Here's an xmtr made with one.
http://antiqueradio.org/lil7.htm

-Bill

Michael,
Well - he said (in a subsequent post) that it had a transformer and
electrolytic. I surmise from that he has DC running around somewhere since
it apparently generates a signal. All one would need to do is trace the
voltage from the secondary to the elusive rectifier. Or one should find DC
across the electrolytic and be able to trace back towards the transformer
from there.
I'm sure he'll figure it out. If he has DC - he has a rectifier hidden
someplace. If he doesn't - it can't work (as he says).
Roger, KL7Q

Michael Black wrote in message
...

"Roger and Ute Brown" ) writes:

Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have
a
tube which sports a rectifier (diode section) and another tube in the
same
envelope). At any rate - a part by part inspection resulting in a
schematic
will tell all!

I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

I don't think the original poster mentioned if there was a transformer,
and
somehow I suspect the lack of one would be a greater indicator of this
route.

Of course, selenium recitifiers may have had a brief enough life that
someone might not recognize one by sight.

Michael VE2BVW

Michael,
Well - he said (in a subsequent post) that it had a transformer and
electrolytic. I surmise from that he has DC running around somewhere since
it apparently generates a signal. All one would need to do is trace the
voltage from the secondary to the elusive rectifier. Or one should find DC
across the electrolytic and be able to trace back towards the transformer
from there.
I'm sure he'll figure it out. If he has DC - he has a rectifier hidden
someplace. If he doesn't - it can't work (as he says).
Roger, KL7Q

Michael Black wrote in message
...

"Roger and Ute Brown" ) writes:

Check the tube base wiring against the 6L6 and
see if everything
goes to the correct pins for such a tube. It's possible you should have
a
tube which sports a rectifier (diode section) and another tube in the
same
envelope). At any rate - a part by part inspection resulting in a
schematic
will tell all!

I thought of that myself. While this transmitter is so simple it has
to be pretty generic, so there doesn't have to be an article about it, I
have seen "single tube" transmitters described in old magazines that
used something intended for AC/DC use, ie a power stage with a built in
rectifier that used a high filament voltage. I'm thinking 50L6, but I'm
not sure if that is right. I don't remember if there was something in an
octal package that ran off 117volts directly.

I don't think the original poster mentioned if there was a transformer,
and
somehow I suspect the lack of one would be a greater indicator of this
route.

Of course, selenium recitifiers may have had a brief enough life that
someone might not recognize one by sight.

Michael VE2BVW

The transmitter can work without a separate rectifier. I recall a circuit
from the 30's in which the transmitter tube is used also as the rectifier.
I think it was in the RCA handbook. I sort of recall an 813 tube, but that
may have been a bit early for the 813. Even in those days, it was not
"state of the art".

Now, I will have to look for the circuit, but the oscillator tube can also
serve as the rectifier. It complicates things a bit and is not in any of
the Handbooks. Never have seen a 6L6 circuit configured that way, but it
can be done and was done in the 30's in at least one circuit.

Colin K7FM




---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04