6m and the 4-400A
 

I am thinking of building up a single ended 4-400A for six. Mainly cuz I've
got a old homebrew HF amp with a good bit of the "stuff" I need to do it
with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I will
only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output circuitry
needed?

Any thoughts?

Dan/W4NTI

Dan/W4NTI wrote:
I am thinking of building up a single ended 4-400A for six. Mainly cuz I've
got a old homebrew HF amp with a good bit of the "stuff" I need to do it
with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I will
only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output circuitry
needed?

Any thoughts?

Dan/W4NTI


If you run the tube in class AB1 it won't need ANY driving power, just
voltage. So with the right input network your 8w exciter should do the
job. You WILL need to neutralize the 4-400A at 6 meters. At this
frequency the tube is below it's self neutralization frequency, so
a conventional neutralization network will work. (above the self
neutralization frequency you have to resort to tricks such as series
tuning of the screen leads).

There was an QST article some years back using a 3-500z on 6 meters.
The tank circuit used a copper tubing coil with a rotating shorted turn
for tuning instead of a variable capacitor. However a Pi network can
work on 6, though you might have to use a 'dual disk' capacitor and
tap the tuning cap down on the tank coil.

BTW the 4-400 is good for use up to about 110mhz.

On Mon, 13 Jun 2005 21:44:05 -0400, Ken Scharf
wrote:

Dan/W4NTI wrote:
I am thinking of building up a single ended 4-400A for six. Mainly cuz I've
got a old homebrew HF amp with a good bit of the "stuff" I need to do it
with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I will
only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output circuitry
needed?

Any thoughts?

Dan/W4NTI


If you run the tube in class AB1 it won't need ANY driving power,

Of course you will.

Thanks Ken, I'll keep looking around. I used to keep all my QSTs, but
with all my traveling...well you know how that goes.

Im a league member, think they have a way to look that stuff up.

Dan/W4NTI

"Ken Scharf" wrote in message
...
Dan/W4NTI wrote:
I am thinking of building up a single ended 4-400A for six. Mainly cuz
I've got a old homebrew HF amp with a good bit of the "stuff" I need to
do it with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I
will only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output
circuitry needed?

Any thoughts?

Dan/W4NTI


If you run the tube in class AB1 it won't need ANY driving power, just
voltage. So with the right input network your 8w exciter should do the
job. You WILL need to neutralize the 4-400A at 6 meters. At this
frequency the tube is below it's self neutralization frequency, so
a conventional neutralization network will work. (above the self
neutralization frequency you have to resort to tricks such as series
tuning of the screen leads).

There was an QST article some years back using a 3-500z on 6 meters.
The tank circuit used a copper tubing coil with a rotating shorted turn
for tuning instead of a variable capacitor. However a Pi network can
work on 6, though you might have to use a 'dual disk' capacitor and
tap the tuning cap down on the tank coil.

BTW the 4-400 is good for use up to about 110mhz.

On Wed, 15 Jun 2005 23:32:44 GMT, "Dan/W4NTI"
wrote:

Thanks Ken, I'll keep looking around. I used to keep all my QSTs, but
with all my traveling...well you know how that goes.

Im a league member, think they have a way to look that stuff up.

If you're a member just go to www.arrl.org and look it up. You should
be able to find whcih issue(s) had what you are looking for, if not
the actual article.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Dan/W4NTI

"Ken Scharf" wrote in message
. ..
Dan/W4NTI wrote:
I am thinking of building up a single ended 4-400A for six. Mainly cuz
I've got a old homebrew HF amp with a good bit of the "stuff" I need to
do it with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I
will only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output
circuitry needed?

Any thoughts?

Dan/W4NTI


If you run the tube in class AB1 it won't need ANY driving power, just
voltage. So with the right input network your 8w exciter should do the
job. You WILL need to neutralize the 4-400A at 6 meters. At this
frequency the tube is below it's self neutralization frequency, so
a conventional neutralization network will work. (above the self
neutralization frequency you have to resort to tricks such as series
tuning of the screen leads).

There was an QST article some years back using a 3-500z on 6 meters.
The tank circuit used a copper tubing coil with a rotating shorted turn
for tuning instead of a variable capacitor. However a Pi network can
work on 6, though you might have to use a 'dual disk' capacitor and
tap the tuning cap down on the tank coil.

BTW the 4-400 is good for use up to about 110mhz.

Wes Stewart wrote:
On Mon, 13 Jun 2005 21:44:05 -0400, Ken Scharf
wrote:


Dan/W4NTI wrote:

I am thinking of building up a single ended 4-400A for six. Mainly cuz I've
got a old homebrew HF amp with a good bit of the "stuff" I need to do it
with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I will
only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output circuitry
needed?

Any thoughts?

Dan/W4NTI



If you run the tube in class AB1 it won't need ANY driving power,


Of course you will.


The TUBE won't require any driving power as it won't draw any
grid current. HOWEVER there WILL be losses in the input coupling
network so some power will be required to generate the required
driving voltage. My point was that 8 watts should be enough.

"Ken Scharf" wrote in message
...
Wes Stewart wrote:
On Mon, 13 Jun 2005 21:44:05 -0400, Ken Scharf
wrote:


Dan/W4NTI wrote:

I am thinking of building up a single ended 4-400A for six. Mainly cuz
I've got a old homebrew HF amp with a good bit of the "stuff" I need to
do it with.

I wonder (since I'm a bit rusty these days), if I can Grid Drive it? I
will only have a basic transverter output (8Watts) available.

Anyone point me to a site or material about the input and output
circuitry needed?

Any thoughts?

Dan/W4NTI



If you run the tube in class AB1 it won't need ANY driving power,


Of course you will.


The TUBE won't require any driving power as it won't draw any
grid current. HOWEVER there WILL be losses in the input coupling
network so some power will be required to generate the required
driving voltage. My point was that 8 watts should be enough.

Thanks for the input.

Dan/W4NTI