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Author Topic: Assistance in completing 4-1000A RF deck  (Read 1442 times)
KB6QXM
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Posts: 106




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« on: February 04, 2008, 04:17:23 PM »

Any suggestions on finding someone that would be willing to assist in the building of my 4-1000A RF deck.

I have all of the components and schematic. I have to find someone who finds building amplifiers interesting with a lot of experience. A sort of HF amplifier Elmer, if you may.

I have put this out to the local community, but with little to no response. I have people that have offered to give me advise, but what I need is someone to assist me in the building, neutralization and testing of the amp. I have offered to compensate the person for their time. No luck!

I work in the Silicon Valley and live near Santa Cruz, CA.  If anyone has any suggestions, I am all ears.

73
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K6AER
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Posts: 3512




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« Reply #1 on: February 04, 2008, 05:58:38 PM »

You’ll not get much reply on this one. Your project is a man hour eater. Most with the necessary knowledge, know this kind of amplifier becomes a labor of love. The metal work alone is the biggest hurtle followed by meticulous detail in building. With just parts alone you could have as much as 150 hours on metal cabinet construction and wiring.

I would suggest looking at handbooks form 1960-1978 for hints on layout and construction using the 4-1000.

Here are some web sites of hams who have built a 4-1000 amplifiers:

http://www.qsl.net/nt8n/project.htm

http://w4emf.gs35b.com/3-1000and4-1000-1978/index.html

More are listed under Google if you look through the many lists.
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W1QJ
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Posts: 1445




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« Reply #2 on: February 05, 2008, 05:30:27 AM »

I agree, Homebrewing an amp is just that, HOMEBREWING, that means YOU DO IT.  There is NO savings on building a legal limit amplifier from scratch yourself.  You won't be saving any money at all.  The whole idea of homebrewing is the personal satisfaction that one gets saying "I built it myself".  If you can follow a schematic and are handy with a soldering iron and some hand tools, there is no reason why you can't do this yourself.  You may have some questions on HOW to best do things, and that is when you come here and ask questions.  I have built a couple of amps from scratch, and I can tell you its fun, but then again it is alot of work.  Before I built my first amp, I got ahold of about 5 ARRL handbooks, they are all loaded with several amplifier projects (homebrew from scratch).  I read all the articles, studied what I did not understand and then read them all over a second time.  When I was ready to build, I took what I liked from several different articles and combined it together to come up with my own project.  Some designs are easier than others, some better than others, you take what you want and work with it. So many hams think they have to use the exact same part as the builder in the book, that is not true,  almost any part can be substituted with something ready available somewhere.  Be advised, there are very lethal voltages in an amplifer and you could kill yourself if you do  not know what you are doing.  There are sections on high voltage power supplies and sections on dealing with working with high voltage.  Before anyone attempts to build an amp, they should be familiar with the precautions.  All the information you need is obtainable in print mostly in the ARRL handbooks and the Bill Orr handbook.  If you want to become an amp builder, you first must train yourself in the theroy of amps and power supplies.  If you are going to get someone to stand over you and wtach you and help you bulid an amp, you may as well have Ameritron or Alpha do it for you.  Get the books, read the articles, pick a project, follow the book, if you have questions, come here and ask.  This forum has a group of users with a wealth of information.  Good Luck  Lou W1QJ
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K0BG
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« Reply #3 on: February 05, 2008, 05:53:38 AM »

You didn't ask, but for what it's worth, I wouldn't use a 4-1000A. A 3-1000 maybe. Tetrodes don't make good amps IMD wise. Building a well regulated bias supply isn't easy either.

As pointed out, the metal work is a bear. You'll need the correct socket for this tube, as well as the chimney. You cannot get by blowing air across the tube, so plan on a good sized blower and adequate plenum.

Here's another thought. The 4-1000 hasn't been made in years. Finding a good one might be a problem, as glass tubes tend to leak at their seals. In any case, you'll have to burn it in first, and hope for the best.

By the way, have you priced a filament transformer yet?

Alan, KØBG
www.k0bg.com
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WB2WIK
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Posts: 20595




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« Reply #4 on: February 05, 2008, 08:13:18 AM »

Is this going to be GG?

I have two homebrew 4-1000 amps (both designed and built by me) sharing a common power supply but both are grid-driven.  No neutralization was required or desired.  The amps have about 19 dB gain (1500W out for 20W drive), and a QRP rig can drive the HF one to about a kilowatt, all in one shot.

I use 4.4kV Ep, 600V Eg2 and a well regulated and adjustable Eg1 supply.  The filament xfmr is in the RF deck with the tube and blower, all the other PSU components are in a separate 140 lb enclosure with casters that sits on the floor.

If you have all the "parts," homebrewing an HF amp is not difficult but all the metalwork can be very time consuming with hand tools.  I drew the punch pattern on graph paper rubber cemented to 16GA preplated CRS sheet metal and took them to a sheet metal shop where they did all the punching using a CNC turret press.  Once programmed, the machine punched 100+ holes in about 30 seconds.  Boy, that saves a lot of work.

WB2WIK/6
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KB6QXM
Member

Posts: 106




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« Reply #5 on: February 05, 2008, 08:38:06 AM »

Yes, the home brew amp you describe sounds a bit like my amp so far. The 5000V@1A power supply sits on the floor with casters. I have the case that the amp will sit on. The only aluminum work that has to be done is for the front and back panel.

I do not want assistance for cost savings, I requested assistance in building the amp as a Teacher/Student situation. To learn the art of amp building and to ensure that the amp is built well.

Nothing more, nothing less.
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WB2WIK
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Posts: 20595




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« Reply #6 on: February 05, 2008, 09:07:12 AM »

Sure.  Obviously you need somebody in your local area who can work with you for a while.

I'd be happy to except I'm 350 miles away, down in L.A.

There are some serious homebrewers up your way...have to look through my log at home to see if I can identify one and if I can, I'll let you know!

WB2WIK/6
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N2AXZ
Member

Posts: 90




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« Reply #7 on: February 12, 2008, 09:07:53 PM »

Yes --- homebrewing an amplifier is indeed a labor of love!  I could have gone out and purchased an amplifier for less than it cost me to build mine, but I used better quality components than I think the commercially available ones use (nice big silver plated air variable caps, Eimac tube sockets, glass chimneys, brand new Peter Dahl Hipersil transformer, etc.). Between raising two boys and going to school at night for two years, it took me a total of eight years to finish mine!  This may sound discouraging, but I can tell you that now that it is on the air, it is one of the greatest sources of pride I have in the shack --- it is my "baby".

I live down in San Diego, so I'm not so close either, but I would be happy to share with you my experiences and pictures (I took photographs of my work as it progressed) and help you out in any way I can.

Good luck!

David, N2AXZ
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KB6QXM
Member

Posts: 106




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« Reply #8 on: February 13, 2008, 04:08:34 PM »

Yes, this 4-1000 uses all of the finest components also. Vacuum caps. High quality parts throughout.

I do not think it is the construction that concerns me. It is the component placement, neutralization and other specifics that I would like some elmering.

You would think that I work in the Silicon Valley that there would be an "old-timer" ham that would enjoy working with me on this project.

Time will tell
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KC9EOT
Member

Posts: 38




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« Reply #9 on: March 03, 2009, 06:53:11 AM »

you need to contact Larry Yaw, w9amr@aol.com He and I build a 4-1000 amp last year. He eats sleeps and plays these things. Very interesting project.
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WB2WIK
Member

Posts: 20595




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« Reply #10 on: March 03, 2009, 08:06:56 AM »

KB6QXM if you're still around: You didn't happen to get the "parts" for this amplifier from John Lawrence N6JL by any chance?

If so, I know the whole "kit" very well!

73

Steve WB2WIK/6
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