I WANTED circuit for 80/40 meters CW transmitter with VFO , 2 or 3
tubes with a final valve 5933wa.
can you help me
TNX Frank

On Sun, 23 Jan 2011 08:54:16 -0800 (PST), Radio Vintage
wrote:

I WANTED circuit for 80/40 meters

Can you specify the types of meters?
Amp, Volt, etc?

TNX Frank

Barry OGrady wrote:
On Sun, 23 Jan 2011 08:54:16 -0800 (PST), Radio Vintage
wrote:

I WANTED circuit for 80/40 meters

Can you specify the types of meters?
Amp, Volt, etc?

This is not funny, Barry.

If it were me, I would look through early issues of the Handbook looking
for transmitters using that final AND for simple three-stage Novice
transmitters and marry the two.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 01/23/2011 11:54 AM, Radio Vintage wrote:
I WANTED circuit for 80/40 meters CW transmitter with VFO , 2 or 3
tubes with a final valve 5933wa.
can you help me
TNX Frank
5933 = 807W

Any transmitter circuit using the 807/1625 as a final can be used.

Most ARRL handbooks from the 50's and 60's had such transmitter
circuits. If you are a member of the ARRL you can download PDF's of QST
articles and can search the back issues by topic.

"Radio Vintage" wrote in message
...
I WANTED circuit for 80/40 meters CW transmitter with VFO , 2 or 3
tubes with a final valve 5933wa.
can you help me
TNX Frank


To add to good advice Scott and Kenneth have given, circuits using the
6146 would also be suitable to copy. I would use a VFO operating on 1.75
to 1.8 MHz for stability with the first tube, doubling in the second
tube. On 80-meters the final would operate straight through. while on
40-meters, you would double in the final. Such an arrangement would
generally not require neutralization with the good shielding of the 5933
(a mechanically ruggedized 807).

73, Barry WA4VZQ

Radio Vintage wrote:
I WANTED circuit for 80/40 meters CW transmitter with VFO , 2 or 3
tubes with a final valve 5933wa.
can you help me
TNX Frank

I'm building a transmitter *similar* to this one. I'm using a 42 tube
as the buffer. So far its working out well. About 20-25 watts out on
80, 40 and 30 meters with a good tone even keying the VFO.

I'm using plug-in coils for the buffer and PA. VFO is running at 3.5 Mc
on 80/40 and 5 Mc for 30.

Unfortunately I don't have a schematic drawn up that I can post since
its still a work in progress.

http://schmidling.com/vfo5j.png

On 01/23/2011 08:07 PM, Nordic Breeds WA4VZQ wrote:
"Radio wrote in message
...
I WANTED circuit for 80/40 meters CW transmitter with VFO , 2 or 3
tubes with a final valve 5933wa.
can you help me
TNX Frank


To add to good advice Scott and Kenneth have given, circuits using the
6146 would also be suitable to copy. I would use a VFO operating on 1.75
to 1.8 MHz for stability with the first tube, doubling in the second
tube. On 80-meters the final would operate straight through. while on
40-meters, you would double in the final. Such an arrangement would
generally not require neutralization with the good shielding of the 5933
(a mechanically ruggedized 807).

73, Barry WA4VZQ


The reason that the 6146 tube generally requires neutralization and the
807 does not is because of the higher gain of the 6146. The 6146 will
draw greater plate current at a lower screen voltage (with the same
plate voltage) than the 807. It is the higher 'gain' of the screen grid
that matters here (since a screen grid tube acts as two triodes in
cascade as far as power gain is concerned). The 6146 is actually better
shielded than the 807 and has less lead inductance which helps
stability. In order to avoid neutralization the 807 requires extra
shielding to keep the grid from 'seeing' the plate. Sub mounting the
tube socket below the chassis so the bottom of the plate is even with
the level of the chassis will do the trick. James Millen sold tube
shields for the 807 which were aluminum cans open at both ends with
spade lugs to mount to the chassis. With the 807 sockets mounted to the
chassis and the shields mounted on the chassis, the tops of the cans
would be just below the level of the bottom of the 807 plates.
Recall the AN-ARC5 transmitters? They sub mounted the 1625 tubes so the
plates were just at the level of the chassis, same idea.

"Kenneth Scharf" wrote in message
...

The reason that the 6146 tube generally requires neutralization and the
807 does not is because of the higher gain of the 6146. The 6146 will
draw greater plate current at a lower screen voltage (with the same
plate voltage) than the 807. It is the higher 'gain' of the screen
grid that matters here (since a screen grid tube acts as two triodes in
cascade as far as power gain is concerned). The 6146 is actually
better shielded than the 807 and has less lead inductance which helps
stability. In order to avoid neutralization the 807 requires extra
shielding to keep the grid from 'seeing' the plate. Sub mounting the
tube socket below the chassis so the bottom of the plate is even with
the level of the chassis will do the trick. James Millen sold tube
shields for the 807 which were aluminum cans open at both ends with
spade lugs to mount to the chassis. With the 807 sockets mounted to
the chassis and the shields mounted on the chassis, the tops of the
cans would be just below the level of the bottom of the 807 plates.
Recall the AN-ARC5 transmitters? They sub mounted the 1625 tubes so
the plates were just at the level of the chassis, same idea.


Neutralization becomes more of an issue the higher you go in frequency.
Most simple entry level transmitters using a single 6146 in the 1950's
and 1960's were not neutralized as the 6146 was only used "straight
through" on 80 or 40 meters. On higher bands it was used as a frequency
multiplier/power stage. The Eico 730, the Elmac AF67, the Heath DX-20,
DX-35, and DX-40, and the Knight T60 used no neutralization. The Eico
723, the Heath DX-60 and the Drake 2NT. however, did. If used on 80 and
40-meters only, I seriously doubt if Frank will need neutralization with
his 5933 as long as the driver tank is located below the chassis and the
final tank circuit is above the chassis. A shield around the base of the
5933 is a good idea, of course.

In the 1936 issue of QST, an article entitled "Operating Notes on the
Transmitting-Type Beam Power Tube" noted:
"Careful tests show that with shielding of this nature the tube has
no tendency to oscillate at frequencies up to and including the 7-Mc.
band; it functions as a true screen-grid amplifier. On 14 Mc. it
will self-oscillate after a fashion, but usually with negligible power
output.
When separately excited, however, it settles down nicely and behaves
like any normal amplifier, showing no tendency to go off on its
own — this, too, when driven by the fourth harmonic of a Tri-tet
oscillator operating at a very low power level. On the whole, therefore,
we have found no occasion for attempting to neutralize the tube,
which is fortunate, because it is always a rather messy job to neutralize
a tube with such low grid-plate capacity."

73, Barry WA4VZQ

"
Nordic Breeds WA4VZQ" wrote in message
... "Kenneth Scharf"
wrote in message
...

The reason that the 6146 tube generally requires neutralization and the
807 does not is because of the higher gain of the 6146. The 6146 will
draw greater plate current at a lower screen voltage (with the same plate
voltage) than the 807. It is the higher 'gain' of the screen grid that
matters here (since a screen grid tube acts as two triodes in cascade as
far as power gain is concerned). The 6146 is actually better shielded
than the 807 and has less lead inductance which helps stability. In
order to avoid neutralization the 807 requires extra shielding to keep
the grid from 'seeing' the plate. Sub mounting the tube socket below the
chassis so the bottom of the plate is even with the level of the chassis
will do the trick. James Millen sold tube shields for the 807 which were
aluminum cans open at both ends with spade lugs to mount to the chassis.
With the 807 sockets mounted to the chassis and the shields mounted on
the chassis, the tops of the cans would be just below the level of the
bottom of the 807 plates.
Recall the AN-ARC5 transmitters? They sub mounted the 1625 tubes so the
plates were just at the level of the chassis, same idea.


Neutralization becomes more of an issue the higher you go in frequency.
Most simple entry level transmitters using a single 6146 in the 1950's and
1960's were not neutralized as the 6146 was only used "straight through"
on 80 or 40 meters. On higher bands it was used as a frequency
multiplier/power stage. The Eico 730, the Elmac AF67, the Heath DX-20,
DX-35, and DX-40, and the Knight T60 used no neutralization. The Eico
723, the Heath DX-60 and the Drake 2NT. however, did. If used on 80 and
40-meters only, I seriously doubt if Frank will need neutralization with
his 5933 as long as the driver tank is located below the chassis and the
final tank circuit is above the chassis. A shield around the base of the
5933 is a good idea, of course.

My experience with 6146's (and one time with a 5933) was that from 40
meters on up, they could be easily be made to self oscillate if they were
lightly loaded. (talking final amplifier stages), and this is where a poor
man's neutralization procedure took place)
When lightly loaded, or better yet with no drive at all, swinging both
the input and output tuning condensers (sometimes referred to as
"capacitors") would induce an oscillation on the
intended band of operation. A single piece of wire used as a negative
feedback condenser could be wiggled about to find a place that tamed things
down.
Only problem with this was that the rough neutralization achieved was
frequency (or band) dependent. Usually it would be "good enough" if
neutralized on the highest band to be used.
Parasitic oscillation was a whole different problem, and didn't seem to
care much if the stage was neutralized or not!!!!!!

Lynn, W7LTQ

"Edmund H. Ramm" wrote in message
...
In "Nordic Breeds WA4VZQ"
writes:

[...]
Neutralization becomes more of an issue the higher you go in
frequency.
Most simple entry level transmitters using a single 6146 in the 1950's
and 1960's were not neutralized as the 6146 was only used "straight
through" on 80 or 40 meters. On higher bands it was used as a
frequency
multiplier/power stage. The Eico 730, the Elmac AF67, the Heath
DX-20,
DX-35, and DX-40, and the Knight T60 used no neutralization.

Nor does the E.F. Johnson Viking Ranger. But it's CW-only variant,
named "Navigator" IIRC, does.

The Eico 723, the Heath DX-60 and the Drake 2NT. however, did.

The Drake 2-NT has a 6HF5 line output valve in the PA stage.

Several of the transmitters I named also used TV sweep tubes. In
general, all of the higher power TV sweep tubes have a higher perveance
than does a 6146. In the case of the 6HF5, the transconductance (plate
amps/grid volts) is 1.6 times that of the 6146. My point was that with
reasonable layout, neutralization would not be required. All of these
transmitters multiplied in the final above 40 meters. If the plate is
tuned to a harmonic while the grid is tuned to the fundamental, there is
far less need to neutralize.

73, Barry WA4VZQ