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Author Topic: ATP-102 and AL-811H  (Read 1110 times)
N8EUI
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Posts: 150




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« on: April 17, 2013, 02:19:41 PM »

Hi everyone,

I acquired a good used Ameritron ATP-102 Tuning Pulser II.  I want to use it to tune up my AL-811H.  Does anyone know the proper combination of adjusting the pulse rate and duty cycle for this unit?

Thanks for any and all replies,
Tom, N8EUI
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N4ATS
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Posts: 851




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« Reply #1 on: April 17, 2013, 02:30:42 PM »

It is way faster to do it using CW , which takes an average of 4 to 6 seconds to tune just about any amp....
« Last Edit: April 17, 2013, 02:40:58 PM by N4ATS » Logged
W9KDX
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Posts: 771




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« Reply #2 on: April 17, 2013, 04:59:51 PM »

Getting back to the question, I can't recall how exactly I figured out what I use (old age) but I was looking at the plate current on my 811H when I found the settings that seemed to be the least stressful.  I have both knobs at 12 O'clock with the duty cycle just a hair to the left.  

I could be dead wrong, but I started with 10 O'clock settings on both and watching the plate current and my external meter, it looked as though 12 O'clock was doing what I wanted while keeping the plate lower than just a plain solid tone.  I assumed based on the instructions:

"To obtain the most accurate meter readings, both PULSE RATE and DUTY CYCLE should
be set far enough clockwise to allow maximum peak power to be indicated on a scope or peak reading meter"

that I wanted enough clockwise to show peak power but not so far as to be a constant tone where I would be defeating the whole point of a pulsar.  In any case, when I tune up with a constant tone the old way, I wind up with the exact same settings and power out as when I use the pulsar on the 12 O'clock settings, but I have a lot less stress on the amp.  I also follow the instructions here:

www.w8ji.com/al811h_and_811_tuning_supplement.htm

and it takes me 5 seconds to tune with just two adjustments as I have already recorded the settings to start with on the amp.

I consider the pulsar to be one of the best investments I have made.  It totally relieved my stress around blowing up my 811H and it cut the time down from minutes (allowing for the cool off time of 15-30 seconds between transmissions) to less than 10 seconds.  Not only that, but I now send out way less noise when I tune.

While I am sure there are those who can tune just about any amp in 4-6 seconds, I prefer to follow the instructions from the guy who designed my 811H.  I also spent a lot of time looking at the sections here:

http://www.eham.net/articles/18364

on what causes stress to the 811 tubes due to exceeding their peak dissipation ratings and it seems to me that tuning at 65 watts and running at 50 watts will provide the longest least stressful life while putting out a bit less than the peak power.
« Last Edit: April 17, 2013, 05:17:54 PM by W9KDX » Logged

Sam
W9KDX
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