Neil, Where Have You Been, Are You OK? As Long As You're OK You Don't Have To Explain

Bruce,

I appreciate your query into my general welfare and am pleased to report that all is well with me and mine. I have not abandoned the board, rather I have been holding back until I have something of value to post. Many times technical questions are answered very well by other posters and I don't have much to add.

I also check this board frequently and enjoy reading the postings from the many very talented and experienced folks who contribute here. The technical material about our hobby posted here of late has been of top quality and equal to that available anywhere I have found. I have also enjoyed your posts about vintage equipment and hope you will post more of these.

There are no part15 projects on my docket at present but some posts by you and RFB about the Lafayette AM transmitter lit a spark about me possibly designing and building a two or three tube transmitter with a bit more safety built in than in that unit. I miss the glow of tubes and might make something prettier than the KK transmitter with bigger tubes so the glow will be readily apparent. Right now this is just an egg waiting to be hatched. (You might have noticed that my avatar is a picture of a transmitting tube which is illuminated almost entirely with the glow of the filament. It was placed on my desk in a socket with the filament voltage applied when I photographed it. I applied a bit of color adjustment to enhance the red.)

I do not know the status of SCWIS but I also have noticed that he has not posted here in a while. Perhaps he or someone who knows will inform us.

Neil

I am relieved to know that all is well
in the land of 8Z.

I remember a year or two ago you had talked
about life being in the way and that you
might have to go away for a while. Then
sometime after that (maybe a week or two)
you came back and told us there was no longer
a problem.

Your post inspired me to think about tube
transmitters. Then I thought about the
infamous Lafayette 990177 phono oscillator,
which has been mentioned on this board before.

It's almost 7:30 AM here, and I am getting
ready to go to job number two.

But I will be back with a new story about
that piece of equipment from - well - not
heaven, but "the other place." The 990177
and it's characteristics were both a blessing and
a curse.

By the way, that glowing tube you have there is
amazing. It looks wonderful. Somebody gave me
a 100TH tube when I was about 13. I had meant
to light it up but never did. It's long gone
now.

And hopefully, maybe we will hear something
from SCWIS, or somebody who knows him.

As always, best wishes,
Bruce, DOGRADIO STUDIO 2

Neil and Bruce, that "build a better tube" project really has my full support and interest. Please go all the way.

Meters for everything.

The A.C. Power
The filaments
the H.V.
grid dips
mA meters
screen voltage
time & temperature

Glass windows to see the tubes

This is only a starting list.

I remember a year or two ago you had talked
about life being in the way and that you
might have to go away for a while. Then
sometime after that (maybe a week or two)
you came back and told us there was no longer
a problem.

You have a good memory. Exactly two years ago this week I was hospitalized for a week for surgery for suspected pancreatic cancer. After the surgery it was determined that I had a benign tumor on my pancreas and I am fully recovered and feeling better than I did for years prior to this. All I have to show from this is a few little dings on my torso and the memory of what the symptoms are like (ugh!).

Back to more interesting things, I attached two non thumbnailed photos of the tube which show more detail. This transmitting tube is from my junk box and the filament obviously is still workable. It would be neat to build a working part 15 AM tx. with this or a similar tube but I haven't yet committed to doing so.

Neil

That is a tube to worship!

But the surgery. It is so wonderful that your recovery has been so successful. The great age of radio is saved by one of its true members being in good health.

"It would be neat to build a working part 15 AM tx. with this or a similar tube"

Would that even be possible? I mean those things do require a considerable amount of voltage on the plates and filament voltage current to get them to conduct and do their thing.

Has anyone ever taken a tube like this that needs 5Kv or more on the plate and 8 or so volts @ several amperes on the filament and made them work with much less voltage and current requirements?

Just curious. I think it would be really cool to see a low power TX operating from one of these..maybe an Eimac 4-500A!

RFB

This tube is a current hog for the filament. I don't remember exactly what the specs are but I used a Flexiformer to get the current and voltage needed. The current was probably amps. It may not be obvious in the photos I posted but the plate was glowing a dull red just from the heat of the filament.

The low operating voltages mentioned by RFB would be something to consider and would probably be off the graphs or data sheets for this tube. Without checking I suspect that this tube may not be a good choice since I pulled it from a 6000 VDC regulated supply where it functioned as a shunt regulator rather than from a transmitter.

Tubes do not depend on the filament to plate voltage for electron emission but to get the electrons to go where they belong (hit the plate) does. Another problem with a tube with the large spacing between the filament and plate is electron transit time which limits the frequency of operation. At low voltages this time increases because the electrons move slower. There are most likely other good looking tubes which will be a better choice. For now I am only playing with the idea and better preparation is needed before jumping into this project.

Neil

Neil - I just wanted to say - I'm glad
you are alright. You must be pretty darn
brave. If I had thought something like that
was happening to me, I don't think I would
have the presence of mind to even be participating
on this board!

As for the tube thing - I have a few comments.

The 100TH I had was supposed to glow bright
white when it is running, or so I was told.
I had two cool big old tubes that were ham
shack decorations for many years. I did not
have the know how to build supplies to light
up those tubes. I think the voltage/amps
would have been huge anyway.

There is a book called, The "Low And Medium
Frequency Radio Experimenter's Scrapbook." It is
a greatly loved publication about Part 15 experimentation
by the late great Ken Cornell, W2IMB.

This book has 11 editions. Those editions came out
between about 1974 and 1989. Finding any edition
of this book is probably impossible. Many people have
copies, but they keep them in locked drawers and
safes. 🙂 Ken had a tube circuit for a Part 15
100 mW AM BCB transmitter in his first edition. I do
not have this - I just remember it. What struck me
is that the transmitter's 6V6 final ran a low
voltage on the plate.

I think it was about 20 volts. (The oscillator tube
still needed 150 volts on the plate to run correctly,
I think. Ken stated that the final 6V6 tube ran
efficiently on the low voltage.) Using morse code on 1575, 1585, and 1595 kHz, Ken was able to do 2 way communication
over an 11 mile path. The transmitter also had provisions
for AM, but of course the range was much much less. And
Ken and his fellow experimenter were using good communications receivers at each end. There is a lot more
to the Ken Cornell story and his books.

I am going to check this. If you Google "Working With
Crystal Control," you will probably still find
a very nice 2 tube 100 mW AM BCB circuit, along with a picture of the actual tube transmitter the person built.
This circuit is connected with some kind of antique radio
club or publication. I will look and see if it is still
on the net, or you guys can. It is a very nice article.

Lastly, the glow of my friends 35W4 tube in his Lafayette phono oscillator was mesmerizing to me, back in 1968.
That particular 35W4 rectifier tube had a beautiful orange glow, and I will never forget it. I plan to write more
about that transmitter, and his 1968 Part 15 station, in the Lafayette radio thread. So stand by for that.

Best Wishes To All Of You
Bruce, DOGRADIO STUDIO 2

P.S. The "Working With Crystal Control"
article is still there. It is from an
Antique Wireless Association publication.
Just Google that title. The picture of
a nice completed practical 100 mW tube
transmitter for the AM BCB is near the end.

Oh - Sorry about the messed up margins in this
post. My eyes are pretty shot, so I won't be
able to fix the margins. Best Wishes Guys

Hi Neil

It been a really long time. This is your old Friend Sean. Sorry I have been
gone for about 2 years or more off the board.

So what is new with you. my health took a turn for the worst and now I am getting
back up on my feet. I also had to deal with my daughter health after
her mother death in an auto accident.

Your Friend
Sean