The manual is rather sparse on this, and I was wondering if anyone out
there has any hints or kinks that will aid in neutralizing the Apache
TX-1 final stage. A brief description of the process would be great,
as the manual doesn't seem to directly address it.

Also, the previous owner seems to have doped (red colored) the final
ceramic tube sockets and the solder lugs, and capacitor leads; Good
idea? (The dope seems to be flaking/failing in some places.)

Thanks to the group,

Lin/KJ6EF
For email responses, remove "nospam_".

On Wed, 07 Jan 2004 06:51:16 GMT, (Space
Charge) wrote:

The manual is rather sparse on this, and I was wondering if anyone out
there has any hints or kinks that will aid in neutralizing the Apache
TX-1 final stage. A brief description of the process would be great,
as the manual doesn't seem to directly address it.

Also, the previous owner seems to have doped (red colored) the final
ceramic tube sockets and the solder lugs, and capacitor leads; Good
idea? (The dope seems to be flaking/failing in some places.)

Thanks to the group,

Lin/KJ6EF
For email responses, remove "nospam_".


You can't do it with a power meter with the hv disconnected. You would
need an rf voltmeter to see the output. Or a scope.

But the easiest way is to leave all voltages on. Tune up into a dummy
load to proper power. Then watch the grid current as you tune the
plate tuning of the final. Grid current should peak slightly at
exactly the dip in plate current. You should also get a peak in output
at the same point. If not adjust the neutralization cap slightly.
Do this on 10 meters.

An increase in grid current on low frequency side of plate resonance
indicates neutralizing cap is too big. An increase in grid current on
the high side of plate resonance indicates the neutralizing cap is too
small.

As you get closer to proper neutralization you will see less of a
change in grid current as you tune the plate through resonance and it
will be smooth.

You may not be able to get everything to exactly coincide but you
should get close.

73
Gary K4FMX

On Wed, 07 Jan 2004 06:51:16 GMT, (Space
Charge) wrote:

The manual is rather sparse on this, and I was wondering if anyone out
there has any hints or kinks that will aid in neutralizing the Apache
TX-1 final stage. A brief description of the process would be great,
as the manual doesn't seem to directly address it.

Also, the previous owner seems to have doped (red colored) the final
ceramic tube sockets and the solder lugs, and capacitor leads; Good
idea? (The dope seems to be flaking/failing in some places.)

Thanks to the group,

Lin/KJ6EF
For email responses, remove "nospam_".


You will not be able to see the output using a power meter when
disabling the plate and screen voltage. An rf voltmeter or scope will
work.

Do this on 10 meters.
The easiest way to neutralize the final is by leaving all voltages on.
Tune up as normal into a dummy load.
Now as you tune the plate tuning control watch to see if you get a dip
in the plate current at exactly the same point that you get a slight
peak in the screen current. You should also get maximum power out at
the exact same point.
If not the neutralization cap needs to be adjusted. Adjust in small
steps and retry for the above.

If the grid current goes up when you tune the plate tuning to the high
side of resonance the neutralizing capacitance is too small.

If the grid current goes up when you tune the plate tuning to the low
side of resonance the neutralizing capacitance is too large.

When you get done the grid current rise should be smooth with less
increase than before and at exactly the dip in plate current. Also the
power output should peak at the same point.

You may not be able to get it exact but it will be ok if you get close
to that.

When properly neutralized you may find that you have less apparent
grid drive available. This is because the feed back before was
enhancing the grid drive.

73
Gary K4FMX

BTW, as I recall the neutralizing "capacitor" is a piece of hookup wire
sticking between the 6146's.

I don't think that I ever really worried about it -- maybe I should have.

Phil

"Space Charge" wrote in message
news:3ffbaaa5.7446798@nntp...
The manual is rather sparse on this, and I was wondering if anyone out
there has any hints or kinks that will aid in neutralizing the Apache
TX-1 final stage. A brief description of the process would be great,
as the manual doesn't seem to directly address it.

Also, the previous owner seems to have doped (red colored) the final
ceramic tube sockets and the solder lugs, and capacitor leads; Good
idea? (The dope seems to be flaking/failing in some places.)

Thanks to the group,

Lin/KJ6EF
For email responses, remove "nospam_".

On Thu, 08 Jan 2004 00:31:57 GMT, "PJ" wrote:

BTW, as I recall the neutralizing "capacitor" is a piece of hookup wire
sticking between the 6146's.

I don't think that I ever really worried about it -- maybe I should have.

Phil

Yup, that's all there is...and the manual goes through a lot of
tune-up for bias level, and clipping, etc, etc, but the word
"neutralization" never appears.

Perhaps on the Apache it's not as critical as one might think.

-Lin/LK6EF
For email responses, remove "nospam_".

Haven't read what others have said, but a "seat-of-the-pants" method of
neutralizing the finals of any HF rig is to load up on 10 metres, preferably
into a dummy load, with a wattmeter in the line. Key the rig and adjust the
neutralizing capacitor so that maximum output, as indicated by your wattmeter,
and dip in final plate current occur at the same time. It works! Cheers es
73, Harry, VE3GRO
Harry MacLean, VE3GRO
500 Riverside Drive, London, ON N6H 2R7
(519) 473-1668