Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
SUPERB Construction - The WA1SSJ Pulse Width Modulator - pics and description




 
The AM Forum
December 06, 2021, 12:38:38 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: SUPERB Construction - The WA1SSJ Pulse Width Modulator - pics and description  (Read 7115 times)
0 Members and 1 Guest are viewing this topic.
steve_qix
Contributing
Member
*
Offline Offline

Posts: 2557


Bap!


WWW
« on: January 22, 2017, 10:44:34 PM »

Wayne WA1SSJ just completed a new 450 Watt (carrier) Pulse Width Modulator /Power Supply for his transmitter.  Wayne completed the RF amplifier a few years ago.  Wayne had been using an analog modulator (with the existing RF amplifier from a few years ago), but built this one because it is considerably more efficient and is a lead-in for a more powerful unit in the future.

This modulator / power supply uses 3 IRFP260N MOSFETs in the modulator output section, mounted on a small heat sink.

Wayne is a superb builder, and takes great care to properly lay out front panels as well as the internals (as the pictures show).

Also shown is the resulting modulation waveform of a 250 cycle triangle wave.  The action of the negative peak limiter (set to around 90%) is clearly visible in the modulation display, as well as the perfect rendering of the triangular waveform in the modulation pattern.

Please excuse the poor pictures.  I used my phone, and it's not too good with pictures unless you're outside in bright sunlight.

Here is the front of the modulator / power supply.


Here is the inside of the unit looking down.  The PWM generator and Overload/Efficiency board are near the front, and the PWM filter and output are visible near the back.


Here is a closeup of the PWM filter.  Note the filter is constructed completely using cores, reducing the filter's size considerably.   This can be done at the kW level as well.


Here is the resultant modulation display of the modulator modulating a 450 watt carrier class E RF deck with a triangle wave.

Logged

High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
KA2DZT
Member

Offline Offline

Posts: 2180


« Reply #1 on: January 22, 2017, 10:54:58 PM »

Some really great looking work.  Wayne does do a great job with HB projects.
Logged
steve_qix
Contributing
Member
*
Offline Offline

Posts: 2557


Bap!


WWW
« Reply #2 on: January 22, 2017, 10:55:24 PM »

Something to note is the total power input to the modulator is shown by the 2 meters on the left.  The input voltage is 130V and the input current is 3.5A or 455 W.

The meters on the right show the output voltage and current.  The output voltage is 45V and the output current is 9.7A, or 436.5 W.

The efficiency of the modulator is 96% (95.9% to be exact).  This is typical for good pulse width modulators.

Logged

High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
VE3ELQ
Contributing
Member
*
Offline Offline

Posts: 258


« Reply #3 on: January 23, 2017, 09:29:08 AM »

And it sounds great too.  Ran into QIX Steve testing out this modulator on Sat. on 3885 khz and we had a nice chat.  Great audio and big signal as usual. Very nice piece of work.
73s  Nigel
Logged

A "Tube Free" zone.
flintstone mop
Contributing
Member
*
Offline Offline

Posts: 5033


« Reply #4 on: January 23, 2017, 10:12:01 AM »

Wayne is an artist.

It's nice when a plan comes together. Metal work and layout and wiring, out of this world.

Logged

Fred KC4MOP
K6JEK
Contributing
Member
*
Offline Offline

Posts: 1173


RF in the shack


« Reply #5 on: January 23, 2017, 11:52:52 AM »

It is a work of art. I imagine the one clip lead in the picture is simply there in honor of your visit, Steve.
Logged
KA0HCP
Contributing
Member
*
Offline Offline

Posts: 1188



« Reply #6 on: January 23, 2017, 12:41:16 PM »

This should be an inspiration to us all! bill
Logged

New callsign KA0HCP, ex-KB4QAA.  Relocated to Kansas in April 2019.
K4RT
Contributing
Member
*
Offline Offline

Posts: 490



« Reply #7 on: January 23, 2017, 02:22:16 PM »

Impressive work Wayne.  Steve, thanks for posting.
Logged
steve_qix
Contributing
Member
*
Offline Offline

Posts: 2557


Bap!


WWW
« Reply #8 on: January 23, 2017, 02:27:43 PM »

It is a work of art. I imagine the one clip lead in the picture is simply there in honor of your visit, Steve.

So Wayne's modulator is actually at my shack, so there are clip leads pretty much everywhere  Wink  The neat, organized construction is certainly an anomaly in my shack.

I should take a picture of the RF deck that I've got hooked up to the modulator.  I built that one (and it definitely does not resemble Wayne's construction in any way!).

Wayne built me a VFO a couple of years ago.  It looks like a commercial, factory produced piece of equipment.  I'll take some pics at some point and post them.
Logged

High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
WB2CAU
Member

Offline Offline

Posts: 342


« Reply #9 on: January 24, 2017, 11:36:28 AM »

I had always heard great things about Wayne's homebrew work, but frankly had no idea the attention to detail until I saw those photos.  Countersinking all of the flat head screws and even engraving the lettering on the front panel.  Then the well-thought-out component layout.  A far cry from what I do for sure!  Wayne is incredible!

And I've never heard Wayne bragging about his own work either, although if he did it would be perfectly justified. 

Unfortunately Wayne will never read these compliments online because he is averse to computers.  Hopefully someone will print out this thread so he can read it on paper.

Thanks for posting that, Steve.

Eric

Logged

"Life is tough, but it's tougher if you're stupid." -- John Wayne
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4293


AMbassador


« Reply #10 on: January 27, 2017, 10:22:17 AM »

Wayne makes beautiful stuff. After the Henniker 'fest in 2007 he invited the AM crew over to his place. I remember seeing his 4-400 rig and was amazed not only at the construction quality, but also by the front panel: no labels, decals, tags, all engraved. Talk about looking 'factory'.

He also shared a story with us about meeting his wife, and how she was one of the Collins girls, building S-Lines and/or KWM-2s back in the day. Some guys get all the luck.  Grin
Logged

known as The Voice of Vermont in a previous life
steve_qix
Contributing
Member
*
Offline Offline

Posts: 2557


Bap!


WWW
« Reply #11 on: January 27, 2017, 11:39:54 AM »


He also shared a story with us about meeting his wife, and how she was one of the Collins girls, building S-Lines and/or KWM-2s back in the day. Some guys get all the luck.  Grin

Yeah, and she's smart, really pretty, a good cook and just a nice person in general !
Logged

High Power, Broadcast Audio and Low Cost?  Check out the class E web site at: http://www.classeradio.org
n1ps
Contributing
Member
*
Offline Offline

Posts: 335


websdr http://sebagolakesdr.us:8901/


« Reply #12 on: January 27, 2017, 07:03:27 PM »

So how did she meet Wayne then?   Grin Grin Grin

Actually I think Wayne does look at a copuker on occasion....Fran allows it! 

Todd I was at that party....it was the first time I saw his work up close.   I felt bad....realizing the crap I build in comparison.   Cool Cool Cool

We may need to do an intervention to get his antenna back up....then we should go north to the home of that K1REC guy. Roll Eyes

~ps
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.074 seconds with 19 queries.