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Author Topic: Big Boy AMP from Germany 15kw  (Read 3213 times)
N8FNR
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Posts: 147




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« on: September 29, 2011, 05:26:52 AM »

http://www.dc9dz.de/en/index.html

Project Tsunami or 3 years of work due to a bet about a crate of Bitburger beer
Burkhard, DF5XV, www.classicbroadcast.de, owns a Monster-PA of R&S called VK20. The live weight of this PA amounts to 1.6 metric tons, it needs a big room on its own with a defined supply and exhaust air and its output reaches frightening 20 Kilowatts, even for RTTY. As a driving transmitter a R&S SK01 is required. Burkhard has an official permission of the BNA for 20 KW on shortwave for broadcast, although not for ham radio. Such enormous values of transmitting power challenge even the creativity of an experienced high frequency engineer. Well, three years ago, the author of this article placed a bet against Burkhard to build a power amplified with more than half the output power of the VK20 in SSB mode, yet would fit the trunk of a compact car as well as a manageable weight. Burkhard's answer: No way! So the race was on!

After three years have passed, the project with working title “Tsunami” is finally completed. Even the additional difficulty of a minimal required input power of only 100 Watts, achieved by every amateur transceiver, in order to attain the full SSB transmit power of approximately 15 Kilowatts was accomplished. A total amplification of about 21 dB is technically very ambitious as it was not the goal to build a power oscillator.

Zack
N8FNR
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ZENKI
Member

Posts: 934




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« Reply #1 on: September 29, 2011, 05:58:19 AM »

Nice to see a ham with such great technical skills. The signal emanating from such a well designed amp at legal limit would be very clean indeed. All I can say is that we far better off with real hams such as this guy who knows what he is doing rather than all the idiots we have on the ham bands today who are using  CB amps and who cause a lot of splatter.  Hams who go  to this much trouble in my experience are technical perfectionists whose standards are set very high and who probably run the cleanest possible transmitters. They probably also have all the test equipment that ensures a clean signal. Contrast this to the LIDS who can run down to the local toy store and buy extreme power amplifiers, take them home and have no technical competence whatsoever or  ability to run these commercial amplifiers without causing unnecessary interference and splatter.  Anyone who is a amp homebrewer and can build a high power amp such as this  is someone  that should be respected and deserves a lot of praise for his efforts. Lets hope he does not sell this amp to  some crazy LID. I saw this amp a while ago on Ebay for 15000 Euros! Me I would rather have a 200 ft tower with 4 high stacks or a Island surrounded by saltwater and some 4 squares, you certainly dont need much more than a kilowatt if you have decent antennas.
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AD4U
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Posts: 2164




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« Reply #2 on: September 29, 2011, 06:00:10 AM »

There are plenty of similar amps in the US.  Many may not be as nicely constructed, but the power is the same (or more).

Dick  AD4U
« Last Edit: September 29, 2011, 06:02:11 AM by AD4U » Logged
N3WAK
Member

Posts: 278




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« Reply #3 on: September 29, 2011, 07:25:49 AM »

Zenki--Hi there.  What's your name and call sign? 

73, Tony N3WAK
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W9GB
Member

Posts: 2623




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« Reply #4 on: September 29, 2011, 04:48:00 PM »

Ironically, I grew up only 50 miles NW of the Gates/Harris plant that builds
commercial AM, FM and TV broadcast transmitters as well as shortwave (SW) transmitters globally.
I toured that plant in 1960s and 1970s and saw many on the production lines (e.g. major NYC TV stations, SW for African countries).
Ceramic tubes were state of the art, with solid-state limited to the initial drivers.
Today, majority of these units use solid-state modules (now in their 3rd generation) are quite impressive (easier to maintain).

In some eastern Europe countries, radio amatuers can legally operate power > 1.5 kW
(but they do have some specific technical ability/safety knowledge requirements) ... one club station was using a
surplus Soviet military 7.5 kW unit (file cabinet sized) .. that had never been used (still packed in crate when they received).

greg
w9gb
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W1IT
Member

Posts: 143




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« Reply #5 on: September 30, 2011, 08:37:57 AM »

 Cheesy
Yo, very impressive. I think we should not be calling who ever designed, fabricated this Monster as a ham, with technical skills.
He is an engineer, who may or may not be a ham. Very neat and professional job as I wonder if I am up to building a class E/H AM rig at 500 watt carrier level.
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AG6K
Member

Posts: 1




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« Reply #6 on: October 02, 2011, 05:32:04 AM »

Nice to see a ham with such great technical skills. The signal emanating from such a well designed amp at legal limit would be very clean indeed. All I can say is that we far better off with real hams such as this guy who knows what he is doing rather than all the idiots we have on the ham bands today who are using  CB amps and who cause a lot of splatter.  Hams who go  to this much trouble in my experience are technical perfectionists whose standards are set very high and who probably run the cleanest possible transmitters. They probably also have all the test equipment that ensures a clean signal. Contrast this to the LIDS who can run down to the local toy store and buy extreme power amplifiers, take them home and have no technical competence whatsoever or  ability to run these commercial amplifiers without causing unnecessary interference and splatter.  Anyone who is a amp homebrewer and can build a high power amp such as this  is someone  that should be respected and deserves a lot of praise for his efforts. Lets hope he does not sell this amp to  some crazy LID. I saw this amp a while ago on Ebay for 15000 Euros! Me I would rather have a 200 ft tower with 4 high stacks or a Island surrounded by saltwater and some 4 squares, you certainly dont need much more than a kilowatt if you have decent antennas.

  True except during contesting since when a rare one shows up one needs to get through pileups quickly and move on.  An extra 10db is a good way to accomplish this.  Another use for 20db amplifiers is for working CA to Europe long path on 80m in the morning. 
- end
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ZENKI
Member

Posts: 934




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« Reply #7 on: October 03, 2011, 01:06:35 AM »

These days the way the price of electricity is going it might be cheaper too buy a  QTH on top of a mountain and install  75  meter yagi! Another alternative would be a sea side location.

Whats is certain is that if you do want to run a 20db  amplifier in the DX Window on 75 meters, make absolutely sure that you  have  superb IMD performance from both your tube with handles and your transmitter.. Not doing will hasten your demise  in the window! This fate has been suffered by many hams  who bought the popular Russian tube King Kong amplifiers and who had absolutely no clue  on how to run a grid driven tetrode cleanly.  Needless to say they made many enemies.


  True except during contesting since when a rare one shows up one needs to get through pileups quickly and move on.  An extra 10db is a good way to accomplish this.  Another use for 20db amplifiers is for working CA to Europe long path on 80m in the morning. 
- end
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AG6K
Member

Posts: 1




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« Reply #8 on: October 03, 2011, 10:51:04 AM »

These days the way the price of electricity is going it might be cheaper too buy a  QTH on top of a mountain and install  75  meter yagi! Another alternative would be a sea side location.
Quote

  I built the Plywood Box 20db Amplifier for under $1300.  The antenna was a 0.3 wavelength elevated vertical.  Since I ran SSB VOX, the # of KWH used was minimal for 80m long path communication from CA to N. Europe.  Compared to using my SB-220 with a 9db yagi, I saved some serious $$ by building a tetrode with handles amp. A Swedish operator (SM4CAN?)  sent over an audio recording of what he was hearing and the Plywood Box was fairly easy to copy.

 
Whats is certain is that if you do want to run a 20db  amplifier in the DX Window on 75 meters, make absolutely sure that you  have  superb IMD performance from both your tube with handles and your transmitter..
Quote

The Plywood box was pretty clean since it had a V-regulated screen. The driver was a TS-830S - which is about as clean as it gets.  No one  complained about splatter.

Quote
Not doing will hasten your demise  in the window! This fate has been suffered by many hams  who bought the popular Russian tube King Kong amplifiers and who had absolutely no clue  on how to run a grid driven tetrode cleanly.  Needless to say they made many enemies.
Quote

  Indeed -- and the guy who caused the most splatter was running a SB-200 driven with every bit of 180w.

Quote
  True except during contesting since when a rare one shows up one needs to get through pileups quickly and move on.  An extra 10db is a good way to accomplish this.  Another use for 20db amplifiers is for working CA to Europe long path on 80m in the morning. 
- end
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