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PDM Modulator and Sequencer finished




 
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Author Topic: PDM Modulator and Sequencer finished  (Read 7094 times)
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W1IA
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« on: March 01, 2005, 07:52:11 PM »

http://home.comcast.net/~w1ia/

New pics of the PDM modulator and sequencer


Brent W1IA

p.s. now web page has thumbnails for dial-up speeds
click for high-res
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N3WWL
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« Reply #1 on: March 01, 2005, 08:11:49 PM »

Very nice, Brent.
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KM5TZ
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« Reply #2 on: March 01, 2005, 08:35:46 PM »

Wow! That looks like some serious overkill - why so many FET's?

David
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W1IA
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« Reply #3 on: March 01, 2005, 08:41:08 PM »

Quote from: KM5TZ
Wow! That looks like some serious overkill - why so many FET's?

David
KM5TZ


Well Dave...I am taking the INR approach to building...I never want to have any stressed components HA!

P.S. The board came from Gary...Thanks again Gary!

Brent W1IA
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K1JJ
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« Reply #4 on: March 01, 2005, 08:46:09 PM »

Wow, you've come a long way in your building skills, OM!

Is that the new Big G  PDM PC board?

Good luck testing it out - I already had MY fun:


Dig the craters:



T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
W1IA
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« Reply #5 on: March 01, 2005, 08:54:45 PM »

Quote from: K1JJ
Wow, you've come a long way in your building skills, OM!

Is that the new Big G  PDM PC board?

Good luck testing it out - I already had MY fun:


Dig the craters:



T


Yup....it G's board....he did a super job on it!
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W1UJR
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« Reply #6 on: March 01, 2005, 09:12:56 PM »

Nice job Brent, but I really dig the "skyhook", that looks like it will rock.

Is that your design and what real estate is required for that?

-Bruce
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W1IA
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« Reply #7 on: March 01, 2005, 09:23:18 PM »

Quote from: W1UJR
Nice job Brent, but I really dig the "skyhook", that looks like it will rock.

Is that your design and what real estate is required for that?

-Bruce


Thanks Bruce.....This is Steve's QIX design...This will be the the 4th one coming on the air. Ke1gf, K1JJ, W2INR and hmmm, who's next? Can't wait to warm up the filaments and warm the coax HA!

Brent W1IA
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WA1GFZ
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« Reply #8 on: March 02, 2005, 08:24:32 AM »

Nice Job Brent! Hey that final layout begs for 4 RF relays to switch in Shunt caps for 160M. That could become a dual band rig?Huh?
The extra cores you added to the transformers should do both bands.
fc

Tom Vu wins the prize for the biggest collection of blown 3 legged fuses
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Vortex Joe - N3IBX
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« Reply #9 on: March 02, 2005, 09:12:02 AM »

Definitely a FB job OM!
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Joe Cro N3IBX

Anything that is Breadboarded,Black Crackle, or that squeals when you tune it gives me MAJOR WOOD!
WA1GFZ
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« Reply #10 on: March 02, 2005, 09:15:24 AM »

Joe,
I agree in TX mode but not RX. Try it you will like it.
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Vortex Joe - N3IBX
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« Reply #11 on: March 02, 2005, 09:54:47 AM »

Quote from: WA1GFZ
Joe,
I agree in TX mode but not RX. Try it you will like it.


Maybe after my Hartley is finished. Is there a relationship between a Heising modded Hartley and "Class-E" one might inquire?

They both work FB on AM!
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Joe Cro N3IBX

Anything that is Breadboarded,Black Crackle, or that squeals when you tune it gives me MAJOR WOOD!
K1JJ
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« Reply #12 on: March 02, 2005, 10:53:31 AM »

Quote from: Vortex Joe - N3IBX
Maybe after my Hartley is finished. Is there a relationship between a Heising modded Hartley and "Class-E" one might inquire?



Joe,

You are the perfect candidate to build a new 10 FET (or bigger)  class E PDM rig!  It would be a great addition to the Vortex.  Join the E gang. The rig,  plus a handful of blown FETS is your entry pass...

Every AMer needs at least ONE super hi-fi, 85%+ efficient, solid state, modern (HOMEBREW) hi-tech AM rig in the shack, caw mawn.   :-)

[That's quite a message]

T
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Frank / WA1GFZ says when he's working near high voltage, as a warning he sings this song by Jay and the Americans: "Come a little bit closer, you're my kind of man, so big and so strong, come a little bit closer, I'm all alone and the night is so long."
xe1yzy
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« Reply #13 on: March 02, 2005, 12:34:06 PM »

Very good job brent!!, congratulations and thanks for share!

Did you have any estimated of the final cost of your rig?

Regards

Pedro XE1YZY
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W1IA
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« Reply #14 on: March 02, 2005, 01:19:54 PM »

Quote from: xe1yzy
Very good job brent!!, congratulations and thanks for share!

Did you have any estimated of the final cost of your rig?

Regards

Pedro XE1YZY


Thanks Pedro......Cost is dependent upon whats in your junk draw. A safe esimate is about 500 dollars.

Brent W1IA
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xe1yzy
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« Reply #15 on: March 02, 2005, 05:22:43 PM »

Quote from: W1IA
Quote from: xe1yzy
Very good job brent!!, congratulations and thanks for share!

Did you have any estimated of the final cost of your rig?

Regards

Pedro XE1YZY


Thanks Pedro......Cost is dependent upon whats in your junk draw. A safe esimate is about 500 dollars.

Brent W1IA


Ok Brent, TNX, well my junkbox its mostly "hollow state" stuff... but I keep my eyes open for parts, I really wants to make some day one of those rigs!

Again, congratulations Brent !
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Bill, KD0HG
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« Reply #16 on: March 02, 2005, 09:09:16 PM »

Quote from: W1IA


Thanks Pedro......Cost is dependent upon whats in your junk draw. A safe esimate is about 500 dollars.

Brent W1IA


Hey, Brent, the next step is to follow in the finest traditions of QST authors like McCoy and come up with a scrounger's PDM modulator..Back in the 1940s it was parts robbed from junked broadcast sets, in the 50s it was parts fromn Teevee sets. Today, how about parts from junk computer monitors, generic computer power supplies, maybe a blown up UPS, switchers from light dimmers or whatever?

Getting it down to $50 would be a cool achievement.
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W1IA
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« Reply #17 on: March 02, 2005, 09:34:44 PM »

Quote from: Bill, KD0HG
Quote from: W1IA


Thanks Pedro......Cost is dependent upon whats in your junk draw. A safe esimate is about 500 dollars.

Brent W1IA


Hey, Brent, the next step is to follow in the finest traditions of QST authors like McCoy and come up with a scrounger's PDM modulator..Back in the 1940s it was parts robbed from junked broadcast sets, in the 50s it was parts fromn Teevee sets. Today, how about parts from junk computer monitors, generic computer power supplies, maybe a blown up UPS, switchers from light dimmers or whatever?

Getting it down to $50 would be a cool achievement.


Gary INR has made it easy to build the modulator with the boards...He is also working on the pdm board. If these become available after we run the prototypes it should make putting these together much easier. The most difficult thing is all the fet lay-out and buss bars. I made up a board for the low voltages and Ted KC3OL had them made by Express PCB. My sequencer has the prototype hooked to it for testing.  Tank circuit parts are the same for any big rig.....other than that fat filter caps 60,000uf at 75 volt or better and a decent isolation transformer for the power supply. A lead on meaty heat-sinks is a must. Tom K1JJ gave me the print to build up the sequencer....allthough KE1GF found a company that makes the sequencer for 39.95.....I was glad I built it though...10 bucks worth of parts and a few hours on the bench.

Brent W1IA

Brent W1IA
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Glenn K2KL
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« Reply #18 on: March 03, 2005, 06:44:06 PM »

Hi Brent!... long time no beer!

Why such a big heat sink on the driver?


Quote from: N3WWL
Very nice, Brent.
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W1IA
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« Reply #19 on: March 03, 2005, 06:59:14 PM »

Quote from: Glenn K2KL
Hi Brent!... long time no beer!

Why such a big heat sink on the driver?


Quote from: N3WWL
Very nice, Brent.


just what I had that was kicking around....doing a complete re-wrok of the rf deck as I type....better layout, lots of work. More spacing and better layout of the shunt caps.....will be finished tonite and ready to mount in rack

73 Brent
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