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Author Topic: "Wood Pecker" Amplifier Tuning Aid  (Read 1084 times)
KW4GT
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Posts: 141




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« on: November 14, 2018, 07:06:53 AM »

I just purchased a used AL-811H and while I'm waiting for it's arrival have been reading through the manual.  I see that you're limited to 7 seconds of full power key down time while tuning - I doubt that I'm going to be that fast until I get a bit of practice.

I've seen tuning aids that put out a sawtooth wave with a duty cycle of around 30%.  If I were to use one of those would the tune up procedure need to be changed or would it be identical to what the manual says?  Am I thinking right that with a 30% duty cycle signal feeding the amplifier that the safe tune-up time would be roughly tripled?

Thanks
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“Anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.'” ― Isaac Asimov
K0IZ
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Posts: 977




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« Reply #1 on: November 14, 2018, 08:33:42 AM »

I have one and it works fine.  Peak power will be same as at 100% but average at the 30% (or whatever yours is set for).  Tuning up a tube amp on less than full drive will not give you the correct settings.  But tuning up with full drive (either 100% or 30%) will.  At 30% you probably can tune up forever!  Just not on top of someone else!  The wood pecker makes extended tune-ups easy and easy on the tubes.  Go for it.
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KW4GT
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Posts: 141




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« Reply #2 on: November 14, 2018, 08:39:33 AM »

 ........At 30% you probably can tune up forever!  Just not on top of someone else!  ......

What about tuning on 7200..... I'd heard that was the national tuning frequency.   Grin
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“Anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.'” ― Isaac Asimov
VE3TMT
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Posts: 992




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« Reply #3 on: November 14, 2018, 09:04:15 AM »

The name of the program escapes me at the moment, but there is one out there that works through your sound card. If you are set up for digital modes then you're all set. You can adjust the tone and duty cycle. I've used it for years.

I can check on the computer when I get home tonight. It also has voice memories for contesting etc.

Max
VE3TMT
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KW4GT
Member

Posts: 141




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« Reply #4 on: November 14, 2018, 10:16:10 AM »

The name of the program escapes me at the moment, but there is one out there that works through your sound card. If you are set up for digital modes then you're all set. You can adjust the tone and duty cycle. I've used it for years.

I can check on the computer when I get home tonight. It also has voice memories for contesting etc.

Max
VE3TMT


I believe you're talking about G7EIX PECKER.  I just found that, looks like it might work for me (If it does I'll send a donation to the author).
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“Anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.'” ― Isaac Asimov
VE3TMT
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Posts: 992




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« Reply #5 on: November 14, 2018, 10:18:36 AM »

The name of the program escapes me at the moment, but there is one out there that works through your sound card. If you are set up for digital modes then you're all set. You can adjust the tone and duty cycle. I've used it for years.

I can check on the computer when I get home tonight. It also has voice memories for contesting etc.

Max
VE3TMT

That's not it. Let me search.
I believe you're talking about G7EIX PECKER.  I just found that, looks like it might work for me (If it does I'll send a donation to the author).
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VE3TMT
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Posts: 992




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« Reply #6 on: November 14, 2018, 10:23:05 AM »

Might be this one:

http://www.sm3wmv.com/homebrew/voice_keyer.php
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N2SR
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Posts: 1208




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« Reply #7 on: November 14, 2018, 11:18:55 AM »

If there was only a way that you could turn up your keyer to say 50 wpm and accomplish the same thing. 

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If no one is doing it that way, there is a probably a very good reason.
KM3F
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Posts: 910




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« Reply #8 on: November 14, 2018, 11:37:56 AM »

I use the radio internal keyer set to 30 wpm dots.
At 50% duty cycle the peak reading power meter on the amplifier or external peak reading meter will show peak power without driving the amplifer full time with a CW signal.
It's no different than actually doing CW mode with a paddle type key.
You just have to make the control circuit to make the function work by closing the DOT control lead with a switch.
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K4RVN
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Posts: 261




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« Reply #9 on: November 14, 2018, 12:56:05 PM »

Jim,
I would suggest that you get a MFJ dummy load to practice tuning on your 811 H. Also use only about 10 watts drive to practice
until you learn the ins and outs of the 811H. The actual current for plate and grid will be a lot less strain on the 811As. Use the manual presets for load and plate tuning to begin the tuning process. Once you determine your actual tuning points for plate and load, copy the blank tuning sheet in your manual and record them for future use. That way you will always be close to the final tune for each band.
A dummy load is always a good tool for long term use to eliminate antenna or amp problems.

Frank
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KW4GT
Member

Posts: 141




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« Reply #10 on: November 14, 2018, 01:08:33 PM »

Yep, I plan on getting a dummy load that's sufficient for legal limit power.  Also, it's not like I'm totally new to tuning up tube equipment.... I had a Collins 32-S1 / 75-S1 for quite a few years. 
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“Anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.'” ― Isaac Asimov
K4RVN
Member

Posts: 261




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« Reply #11 on: November 14, 2018, 02:15:57 PM »

Jim, I have had 4 Ameritron amps and they all tune the same way for me. AL 811, AL80A, AL 80B, AL 800H. Never owned any Collins gear. Good luck. My 1KW mfj dummy load is only good at that for a very short time and I mean short. I usual tune up with about 10 to 20 watts drive then touch it up 30 seconds for max out at the power level I operate. After many years you can do it in a few seconds and not have to think really hard as you probably know. Enjoy your amp.
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