The coils bring the amplifier into resonance in a particular frequency range, they don't increase or decrease output power.
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Apollo 500 amplifier
- Thread starter Jimbo165
- Start date
I don't 100% agree with that statement.
Adjusting the coil in the Tank circuit can increase output power. This changes the "Q"...
However a simple wattmeter will not tell you this.
You may see increased output, BUT unless your looking at the Fundamental Frequency of the desired operation on a spectrum analyzer or tuning the Tank circuit with a Grid Dip meter, you will have no idea whether you have made a proper adjustment correction or not.
Thus, yes 999 most generally leave them alone.
All the Best
Gary
Flame suit ready here ya'al
The previous answers are dead on.
You may see an increase on your watt meter. But that increase could be in another band
not 11 meters. Hams in my opinion. After 6/10s of a century being on earth. Even Hams
who were 11meter mud ducks at one time. Loath CBers running DIRTY linear Amps.
You may be looking at the amount of Dreaded I.M.D. your box is putting out. This
power showing on your
meter can be interfereing with legal licensed Amateur bands. Fire, Police buisiness,
Airport communications verbatum. Shoosh. Eventually. I'll get a software spectrum
analyser. Pricy. You need to get an LCR meter. Wind your own tank coils.
Not perfect. I go to a free band channel above 40. Check with an acquantance
that his S meter is rising. To try to ensure thw Watts I see on the meter are actually
on that frequency.
You do not have enouph iron in that box to push 400 bananas for any length of time
on AM. ALL the Sweep tube Boxes were desighned For full output on SSB.
On AM they get run on LOW POWER.
Google is your friend. Start with the basics. READ Learn. With 2X driving 4 700v or 800v
at the plate. 400W is possible. NOT RECOMENDED.
Have fun..................High Voltage Kills. Don't shock youself !
You may see an increase on your watt meter. But that increase could be in another band
not 11 meters. Hams in my opinion. After 6/10s of a century being on earth. Even Hams
who were 11meter mud ducks at one time. Loath CBers running DIRTY linear Amps.
You may be looking at the amount of Dreaded I.M.D. your box is putting out. This
power showing on your
meter can be interfereing with legal licensed Amateur bands. Fire, Police buisiness,
Airport communications verbatum. Shoosh. Eventually. I'll get a software spectrum
analyser. Pricy. You need to get an LCR meter. Wind your own tank coils.
Not perfect. I go to a free band channel above 40. Check with an acquantance
that his S meter is rising. To try to ensure thw Watts I see on the meter are actually
on that frequency.
You do not have enouph iron in that box to push 400 bananas for any length of time
on AM. ALL the Sweep tube Boxes were desighned For full output on SSB.
On AM they get run on LOW POWER.
Google is your friend. Start with the basics. READ Learn. With 2X driving 4 700v or 800v
at the plate. 400W is possible. NOT RECOMENDED.
Have fun..................High Voltage Kills. Don't shock youself !
Here's how to tell if an output coil is not set properly. Changing tubes from one brand to a different brand can affect it.
Turn the plate tune around one full turn while the amplifier is keyed. The wattmeter should show TWO separate peaks in that one full turn of the knob.
Those two peaks might be close to each other. Might be 180 degrees apart.
What matters is that you see TWO of them.
If you do, there probably is not much to be gained molesting the coil attached to that Plate Tune control.
** BUT **
If you see only one peak, a glance at the control behind the panel will show one of two things. Either the plates of the control are as far apart as they will go.
--OR--
You'll see that the plates are meshed fully, as close together as they'll go.
If you see either of these conditions and that ONE peak only, the coil is not tuned properly, and needs to be adjusted. That will bring the peak on the Plate Tune control back into range between the two extremes of the knob's travel.
73
Turn the plate tune around one full turn while the amplifier is keyed. The wattmeter should show TWO separate peaks in that one full turn of the knob.
Those two peaks might be close to each other. Might be 180 degrees apart.
What matters is that you see TWO of them.
If you do, there probably is not much to be gained molesting the coil attached to that Plate Tune control.
** BUT **
If you see only one peak, a glance at the control behind the panel will show one of two things. Either the plates of the control are as far apart as they will go.
--OR--
You'll see that the plates are meshed fully, as close together as they'll go.
If you see either of these conditions and that ONE peak only, the coil is not tuned properly, and needs to be adjusted. That will bring the peak on the Plate Tune control back into range between the two extremes of the knob's travel.
73
Here re a few links to get you started on the road to being a Golden Screwdriver sweep tube amp GURU. Read it. Then Google lets say. What is Grounded Grid AB1.
If you put the time in. In no time. You will join the Sweep Tube Screw Driver club !
Oh I do not use Google anymore. I use DUCK and GO search. Faster. No tracking.
Here is a few Links to get you started. I now use Duck and Go search engine.
no tracking annoying pop ups etc.
https://www.robkalmeijer.nl/technie...hniek/hambladen/qst/1955/06/page21/index.html
"Build a Tube Type Linear Amplifier For CB Or Other HF Bands" Utube
https://wb0nni.dakotamade.com/rfout.html
http://www.somis.org/D-amplifiers4.html
https://www.w8ji.com/Vacuum_tube_amps.htm
Ive only seen a Pi-L Tank "Network setup on a couple of production Sweep tube amps.
For possibly 6meter or 15meter bands. Basically Palomar Skipper 300 designs. I have them. One day will play. Convert them to 11 meter. Simple. Measure the inductance
of one of my mint Palomar Skipper 300 Tank Coil. Then wind a better equivalent.
With the same inductance. Cheap better than pure copper tubeing. Even silver plated copper tubing. Found in nearly any auto parts store by the foot. Very low Q.
I bought complete rolls at Napa auto parts.
Nickel Copper Brake tubing. 3/16....1/8...1/4 O.D.
My method.
I do not know.
1) Output impedance of Tubes
2) I do not have a Grid dip meter
3) I do not know the Math. Nor do I care to learn. I am a Geezer.
But I can measure with my LCR meter the original tank Coil.
Inductance
Q
300w to 400 bananas. I will start with 1/8 OD
Wind a Tank 15% or so higher Inductance than original.
" " " " or so lower " " "
Mine always have a higher Q than the original. Always between 10 to 15 MAX Q.
I check the Sweeps for GM. Transconductance FIRST. Wasting your time.
If you do not know. The quality and GM of the tubes !!!!!!!!!!!!!
I have clip jigs I made. Solder them in. Drop in Tank coils. Stretch. Sqeez.
Some times I go to 1/4 OD. Even Brass strips I twisted into a coil.
But I find a tank coil with 12-13 Q that resonates. With Maximum output.
And without a Grid dip meter. Which will only get you close anyway. When voltage
current is applied to the tank. The resonating frequency will not be what the meter
showed.
Box is tuned to a solid block of continuos channels towards 10 with low SWR.
And full output. Always a little IMD. They r Sweep tubes you know.
On 11 meters of course. I got a feel for it after all these years. And a big box of Tank coils already made !
Simply copy the width number of turns of the original. LCR meter if you want to
succeed fast.
Your Tank is simpler. A PI network. Duck & Go IT Pilgrim !
Tuned input filter.
A PI-L instead of a PI. Perhaps a Sweep tube Amp might meet current FCC I.M.D.
requirements. I dont care anymore honestly. The Hams in my area use their Ham rigs
on CB. An FCC NoNo. I run my dirty Phantom 12 tuber in my new Platform. Yep.
They know when I am around. They think that Phantom is bad. The Maco two piece
go's in the car soon. With 11 N.O.S. M-2057. 13 volt DC fully regulated fillament
supply. A custom 4KVA high voltage supply. And like the D&A's. A relay switching the
HV plate supply in and out.
It can be fun if you learn the basics !
4Fingers&aThumb
If you put the time in. In no time. You will join the Sweep Tube Screw Driver club !
Oh I do not use Google anymore. I use DUCK and GO search. Faster. No tracking.
Here is a few Links to get you started. I now use Duck and Go search engine.
no tracking annoying pop ups etc.
https://www.robkalmeijer.nl/technie...hniek/hambladen/qst/1955/06/page21/index.html
"Build a Tube Type Linear Amplifier For CB Or Other HF Bands" Utube
https://wb0nni.dakotamade.com/rfout.html
http://www.somis.org/D-amplifiers4.html
https://www.w8ji.com/Vacuum_tube_amps.htm
Ive only seen a Pi-L Tank "Network setup on a couple of production Sweep tube amps.
For possibly 6meter or 15meter bands. Basically Palomar Skipper 300 designs. I have them. One day will play. Convert them to 11 meter. Simple. Measure the inductance
of one of my mint Palomar Skipper 300 Tank Coil. Then wind a better equivalent.
With the same inductance. Cheap better than pure copper tubeing. Even silver plated copper tubing. Found in nearly any auto parts store by the foot. Very low Q.
I bought complete rolls at Napa auto parts.
Nickel Copper Brake tubing. 3/16....1/8...1/4 O.D.
My method.
I do not know.
1) Output impedance of Tubes
2) I do not have a Grid dip meter
3) I do not know the Math. Nor do I care to learn. I am a Geezer.
But I can measure with my LCR meter the original tank Coil.
Inductance
Q
300w to 400 bananas. I will start with 1/8 OD
Wind a Tank 15% or so higher Inductance than original.
" " " " or so lower " " "
Mine always have a higher Q than the original. Always between 10 to 15 MAX Q.
I check the Sweeps for GM. Transconductance FIRST. Wasting your time.
If you do not know. The quality and GM of the tubes !!!!!!!!!!!!!
I have clip jigs I made. Solder them in. Drop in Tank coils. Stretch. Sqeez.
Some times I go to 1/4 OD. Even Brass strips I twisted into a coil.
But I find a tank coil with 12-13 Q that resonates. With Maximum output.
And without a Grid dip meter. Which will only get you close anyway. When voltage
current is applied to the tank. The resonating frequency will not be what the meter
showed.
Box is tuned to a solid block of continuos channels towards 10 with low SWR.
And full output. Always a little IMD. They r Sweep tubes you know.
On 11 meters of course. I got a feel for it after all these years. And a big box of Tank coils already made !
Simply copy the width number of turns of the original. LCR meter if you want to
succeed fast.
Your Tank is simpler. A PI network. Duck & Go IT Pilgrim !
Tuned input filter.
A PI-L instead of a PI. Perhaps a Sweep tube Amp might meet current FCC I.M.D.
requirements. I dont care anymore honestly. The Hams in my area use their Ham rigs
on CB. An FCC NoNo. I run my dirty Phantom 12 tuber in my new Platform. Yep.
They know when I am around. They think that Phantom is bad. The Maco two piece
go's in the car soon. With 11 N.O.S. M-2057. 13 volt DC fully regulated fillament
supply. A custom 4KVA high voltage supply. And like the D&A's. A relay switching the
HV plate supply in and out.
It can be fun if you learn the basics !
4Fingers&aThumb
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