Tube Lighting

Here is a word of caution for those who seek to obtain better
square wave modulation and low frequency response. It is
certainly possible to switch the RF at the pre-driver or driver
transistor in a CB and thus generate very clean square wave
modulated RF with fast rise and fall times and no lower limit
to the frequency response. However, at low modulating
frequencies such as 20Hz the plasma ionisation will be lost
during the "off" half of each cycle, and the tube may not
reignite at the next half cycle.

The natural temptation is to adjust the tuner so that the tube
does restart on each modulation cycle, and then to wonder
whether it is safe to leave it running with the resulting high
SWR and vibrating meter needle. In my case it wasn't and the
amplifier transistors failed after a short while. I didn't
learn the lesson and allowed the same thing to happen with the
new amplifier! The four MRF455 transistors were expensive, and
I am not experimenting with frequencies below 300Hz at the
moment.

Maybe some of the complementary ways of wrapping the tube will
overcome this problem, or perhaps less than 100% modulation
would allow the tube to stay alight while still running with an
acceptable SWR. But if you have to set the tuner differently
for starting, and you are intending to modulate at low
frequency other than by using the CB modulator, be aware of
the possible outcome! -- Bob Haining



The ability to light a tube easily does depend upon several
factors, but there is one primary factor that counts above all
others. It is known as the "swing" of the linear. That is the
idling power of the linear with the tube lit but no frequency
being modulated Vs the power of the linear with the tube lit
and modulated. This situation is seen by anyone with a Kinnaman
generator. As the Kinnaman switches frequencies, it stops
outputting a frequency for 12 seconds. this corresponds to a
"dead key" state.

After I cut the power leads to my CB, linear, and fan to a 3
foot length and shortened the main ground wire from my CB to
the antenna tuner to 3 feet my Palomars swing jumped
considerably. My Palomar on medium power will now dead key at
60 watts and swing to 125 watts ( on my meter with a 912 balun
) at 10k frequency . It used to swing from about 90 watts dead
key to 118 watts at 10k.

The larger swing means that there is a sudden jump in power
that makes the tube easier to light. I have tried out 6
different bubble tubes in the past two days since the
shortening of the power leads and every single one of them is
absolutely no trouble at all to light now.

Jim

----------------------------


>From ma@lightlink.com Mon Nov 2 22:50:14 1998


BR Tuning #1: Easy Argon Tube Ignition

Copyright (c) November 1998 by Laurence D. "Mike" Hammer. All
Rights Reserved. Please only send this entire paper to other
folks, as some of the following won't work properly taken out
of context.

This is the first in a short series intended to get some of my
experience out to those who might find it useful. I've now
spent about 6 months playing with different configurations
based on the Jim Bare design, watching single-celled critters
blow up or not under a microscope, and wondering what just
happened to which expensive component (!). Seeing the same
questions come over the list time and time again it seems like
a good time to get some of this out.

NOTE: Please read the following with a touch of humor; I've
been told I'm a bit dry. Also remember: Usually things aren't
as bad as they seem, though I've heard much worse than the
stories below! I've found well-built BRG's to be pretty darn
rugged.

DISCLAIMER: I have tried the following with several tubes and
it worked every time. Unfortunately I cannot guarantee it will
work for you on your device because I don't know how your
device is constructed nor do I know your level of technical
expertise. Most of all I am not responsible and cannot be held
liable for any damage you might do to your device as a result
of trying to perform this modification, dropping your tube
etc. I offer this advice to you for no charge with the
stipulation that you (a) not take credit for it, it's a
combination of Jim Bare's (22 ga wire wrap), Bill Cheb's
(copper sleeves) and my ideas and work (lengths, mix of parts,
experimenting and typing all this in); and (b) that by trying
it you agree to hold us all free of any liability whether
perceived or implied. No charge, no liability, it's that
simple. Also, I use my BRG device on single-celled organisms
and do not make claims for the efficacy of this modification or
the BRG in any other application. The standard medical
disclaimer applies, especially the part about if you think you
are sick seek the advice of a certified medical doctor.

Complete parts and tools required lists are given at the end of
this paper.

I hope to post pics of performing this mod on the web soon,
will notify the list when that happens.


The Problem:

You've ordered Jim Bare's manual and video, gone through the
agonizing process of tracking down, ordering the correct parts,
receiving incorrect parts, sending those back and finally
receiving the correct parts. You've carefully put it all
together. Holding your breath you turn it all on for the first
time and -- the needles on the 949E antenna tuner go straight
up, indicating infinite SWR, and you can't get your sparkly new
argon tube to light. Twisting the knobs for 20 seconds or so
you still can't get the tube to light. You then remember to
shut off the CB, well after the suggested 10 second limit. Did
you just fry the output transistors in the amplifier, you
wonder...

Or, you got it to light but nothing you do brings SWR below
1.6:1, and the back of the CB and the balun get very very hot.

Or, you've swapped cables and perhaps even tubes but still
can't get SWR below 1.4:1.


WHAT NOW?

Believe it or not these are all related problems. In the basic
BRG (as Dr. Bare's device is often known) everything seems to
affect SWR, power output and component heat, sometimes trading
off one for another and sometimes making all worse or better.
The "output end" of the device is unstable for a variety of
reasons at different times. What we are looking for here is a
simple, easy way to (a) get argon tubes to light and stay lit
between frequency cycles if you have a programmable function
generator, and (b) if possible lower SWR or at least not
increase it while making the device easy to light.

What I would like to pass along is a relatively simple mod that
will help your argon tube unit light right off, while either
not increasing SWR or perhaps even decreasing it by .1 to .2
SWR units. Next paper will deal with lowering SWR to 1.4:1 or
even 1.2:1 by simply swapping a few cables.



APPLICABILITY:

This mod applies ONLY to Bare-Rife generators that use argon or
partially-argon tubes that are NOT fired through any tube-end
internal electrodes. I have tried this with a Randazzo 80%/20%
argon/other gas mix tube, a Cheb 99%/1% argon/other gas mix
tube, and a Cheb "super H-gas" mix tube. Every time it made
the tube easier to light, in one case allowing me to run a tube
that was unlightable otherwise. (It had become irreversibly
corrupted -- I test things a lot.)

If you have a Cheb Phanotron, end-fired or other special-type
tube, this mod isn't for you. Don't even think of trying it.
Besides, Phanotrons light right off, even at 50 watts, and run
at pretty low SWR anyway. If you're dissatisfied with your
Phanotron you might as well give up now, as you'll find argon
tubes totally frustrating, especially without this mod.



HOW-TO STEP-BY-STEP:

Plan on two hours to do this whole procedure once you have all
the parts and tools gathered. That way you won't rush. My
last set went together in about 30 minutes, but I've made a few
sets and was in practice.


Step 1. First, measure the diameter of your tube at the small
ends. What you are going to do is make two copper sleeves from
copper plumbing pipe that will fit over the ends of your tube,
sliding up past the electrodes (if your tube is so equipped) so
they are over the gas section of the tube. So obviously you
want to buy a piece of pipe that slides on easily. If the pipe
is tight it will crack the glass when the glass expands as the
tube gets hot. And, you want to leave enough room so you can
put a single layer wrap of thin cotton under the sleeves to
insulate the glass from the heat of the copper sleeves (and
provide a bit more capacitance, but that's getting technical).

What I did was measure my tube with a dial caliper (used to be
a mechanic) and add 0.080" to the result. I took my calipers
down to the local hardware store and had a nice young man cut
me two 2" (that's two inch) long pieces of copper pipe that had
the smallest internal size bigger than that. You don't want
the pipe too big -- if it's more than 1/4" bigger it won't work
right. I've been able to find appropriate sizes of copper pipe
for all my tubes so far, and each time have only had to pay for
4 inches of tubing, which is about 35 cents US. And they cut
it for me for free when I asked, how nice. Wish I'd asked the
first time.

If you aren't sure what size to get, GENTLY wrap your tube up
in a BIG towel, put it in a box to protect it from breaking and
bring it with you. Find the smallest diameter copper pipe that
the tube slides into with some room left over, and have the
nice man cut you two 2" long sections of that pipe.

BE VERY CAREFUL WITH YOUR TUBE!!! DON'T BREAK OR DAMAGE IT NO
MATTER WHAT!!! Tubes are expensive. Nuff said.

If you can't find a nice man don't panic, just buy a short
section of properly-sized copper tubing and bring it home.
Using a hacksaw with fine teeth cut two 2" (that's two inch)
long pieces off.

So now you have two, 2" long pieces of copper pipe that slip
easily over the ends of your argon tube. Good.


Step 2. Using a partly round or completely round file, file
the ridge off the inside of each end of the copper pipe
pieces. This ridge is formed when you cut copper pipe, and it
only takes about two minutes to get rid of it. If you don't it
will pinch your tube and possibly break it, so file away until
the entry into the pipe is nice and smooth. A bit of chamfer
here will help when you slide the piece onto your tube -- I
usually file them so there is a 45 degree angle going into the
center of the pipe, which makes putting them on very easy. Do
this for both ends of both pieces of pipe, or four times.


Step 3. Perpare the eyelets. Using a pair of wire cutters cut
the plastic cover off the eyelet if so equipped, and slice open
the wire-holding part the long way. Now grab the flat end of
the eyelet with a pair of pliers and, using a pair of
needle-nose pliers bend the wireholding part that you just slit
out so that it becomes almost flat. You are going to solder
this part onto the copper sleeve so you can bolt the connection
wires to the copper sleeves. Bend the eyelet part (with the
hole in it) so it makes about a 45 degree angle from being
straight.


Step 4. Now you want to solder an eyelet on to each copper
sleeve. This is the tricky part. Using a plumber's blowtorch
(aka propane torch) heat the copper pipe up til it's real hot
right at the end. You want it just below glowing hot. Put
some paste flux on the copper pipe to clean it, then solder the
non-holed part of the eyelet to the outside of the copper pipe
right at the end. The result should be that the bend you put
in the eyelet is at the end of the copper pipe, and the holed
part of the eyelet sticks out past the end of the pipe. Then
do this with the other piece of copper pipe so you have two of
them. Soldering on copper pipe is tricky so it might take a
few tries; be a bit careful with the heat so you don't melt the
copper pipe. If it starts glowing red where you're applying
the heat it's too hot. Solder one eyelet on each piece of
copper pipe, so you'll do this step twice too.


Step 5. Now cut two 24" long pieces of either Radio Shack
monster wire (8 gauge stranded copper if memory serves) or 1/4"
braided ground strap. You'll use one for each end of the tube
to connect from the copper pipe pieces to the output posts of
your balun.


Step 6. Now just like when you assembled your BRG in the first
place, solder one ring eyelet connector to each end of the two
wires you just made in Step 5, for a total of four separate
connections. Cover the wire with sufficient-sized tubing for
safety if not already covered. So now you have two wires with
eyelets on each end and two sections of copper pipe with
eyelets sticking off the ends.


Step 7. Now cut two pieces of light cotton from an old t-shirt
or something similar. Make these pieces 2" wide plus about
1/4", and just long enough to wrap around the tube once plus
1/4". These will go around the tube under the copper sleeves.
(I have also used card stock paper and typing paper, each of
which worked as well as it was thick. Contrary to what you
might think the paper doesn't burn! Consider these if the
tube-to-pipe fit is tight.)


Step 8. Wrap one piece of cotton fabric around your tube so
the tube sticks out about 1/4" and slide a copper sleeve over
it so the eyelet points toward the center of the tube. Then do
the same thing on the other side, so you have a copper pipe on
each end of the tube with the eyelets pointing toward the
center of the tube.


Step 9. Now take the section of 22 gauge wire and solder one
end to one of the copper sleeves. This is easiest if you
"tack-solder" it to a bit of solder sticking out from under the
eyelet you soldered on previously.

WARNING: DO NOT SOLDER THE OTHER END TO THE OTHER COPPER
SLEEVE. IN FACT NEVER LET THE WIRE TOUCH BOTH SLEEVES AT ONCE
-- KEEP THE WIRE AT LEAST 1-1/2" AND PREFERABLY 2" AWAY FROM
THE OTHER COPPER SLEEVE. IF YOU TOUCH THE WIRE TO BOTH SLEEVES
WHILE YOUR DEVICE IS OPERATING YOU WILL FRY YOUR AMPLIFIER AT
LEAST!!! So you've been warned.


Step 10. Wrap the 22 gauge copper wire around your tube so
that you use all of the wire 2" or so before it reaches the
other copper sleeve. Slip the end of the wire back under
itself so the last loop is a circle.

Jim Bare has a drawing of this wire wrapping on pages 59C and
59D of his manual for bubble- and straight- tubes
respectively. The changes are that copper sleeves are used
instead of the hose clamps shown, the 22 gauge wire forms a
completed circle at it's end, and the gap between the wire and
the "far end" sleeve should be 2" not 1/4", primarily for
safety. Don't wanna blow that amp. Nope.


Step 11. Connect each wire to the balun at one end and, using
the nut and bolt, to the eyelet on the copper sleeve at the
other.


Step 12. Adjust your BRG's antenna tuner to 8/8 on the
transmitter and antenna controls respectively, set your
function generator to your favorite number (between 1000 and
1550 if you want me to give you a start), and turn on your
unit. The tube will most probably light right up -- now tune
for best SWR and see if it works better in terms of lower SWR
and/or higher forward power. If the tube doesn't light dial
the Transmitter side down (toward lower numbers) slowly until
it lights up, then dial it slowly back up and let the tube
settle into its lowest SWR reading. You will most probably
also have to adjust the Antenna side to achieve best SWR. Each
tube has its own favorite settings so I won't try to give exact
numbers here.

What you have done is constructed a new "tube coupling" system
for your BRG, one with more surface area for better coupling
and with the wire to decrease the gap that must "fire" to
ignite the tube. Once in operation the wire becomes
insignificant in terms of capacitive coupling.

You may find, if you run a Kinnaman, that your tube now stays
lit during the "between" or off cycle rather than winking out.
You may also find that your rig now runs very differently than
it did before no matter what FG you use. I find that the
lengths of the cabling between the CB and linear, and linear
and antenna tuner, affect SWR and power more than any other
single factor in the basic Bare design, in fact allowing you to
'tune' a device to work better in a particular band of
frequencies as programmed into the FG. But that's the topic of
the next paper...

REMINDER WARNING: DO NOT SOLDER THE OTHER END OF THE 22 GAUGE
WIRE TO THE OTHER COPPER SLEEVE. IN FACT NEVER LET THE WIRE
TOUCH BOTH SLEEVES AT ONCE -- KEEP THE WIRE AT LEAST 1-1/2" AND
PREFERABLY 2" AWAY FROM THE OTHER COPPER SLEEVE. IF YOU TOUCH
THE WIRE TO BOTH SLEEVES WHILE YOUR DEVICE IS OPERATING YOU
WILL FRY YOUR AMPLIFIER AT LEAST!!! So you've been warned
again.


ONE POSSIBLE complementary:

If you have some patience and like fabricating, one complementary
to the copper sleeves is to visit Ralph Hartwell's web site and
read about his "balun-less twisted transmission line" design.
I have received both good and bad reports about this setup.
The good reports (the majority) say that it gives very rapid
tube lighting and achieves a very low SWR, often 1.0:1 (or
perfect impedance matching). The bad reports (a minority) say
that this modification decreases the "felt" and observed
effects of the device, in one case to the point where the BRG
stopped producing MOR effects on single-celled organisms. As
always, maybe no 100% perfect solution.

Yet Another Disclaimer: I have not yet built an output coupling
according to Ralph's design, but it's on my list of things to
try next Spring or so at the rate I'm going down my list. Darn
broken wrist.


Complete Parts List for the copper sleeve mod:

Quantity Part
2 2" copper pipe sections
6 12 gauge ring eyelets
1 oz pipe soldering flux
8" electronic solder
48" bare 22 gauge copper wire
2 1/2" 6-32 electrical screws
2 6-32 electrical nuts
2 24" sections of Radio Shack monster wire pulled apart (one piece
of
wire), or 1/4" grounding strap, or 3/16" grounding strap
2 23" sections of aquarium tubing to fit over the above, if
uncovered

Tools required for the copper sleeve mod:

Hacksaw (if the hardware store doesn't cut the pipe)
Wire cutters
Needle-nose or regular pliers
Round- or half-round file
Plumbers torch
Soldering iron
Screwdriver
Small adjustable wrench

As always, Good Fortune,

Mike Hammer