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Title: PDM Modulator and Sequencer finished Post by: W1IA 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 Title: PDM Modulator and Sequencer finished Post by: N3WWL on March 01, 2005, 08:11:49 PM Very nice, Brent.
Title: PDM Modulator and Sequencer finished Post by: KM5TZ on March 01, 2005, 08:35:46 PM Wow! That looks like some serious overkill - why so many FET's?
David KM5TZ Title: PDM Modulator and Sequencer finished Post by: W1IA 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 Title: PDM Modulator and Sequencer finished Post by: K1JJ 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: (http://home.comcast.net/~k1jj/wsb/media/254120/site1071.jpg) Dig the craters: (http://home.comcast.net/~k1jj/wsb/media/254120/site1072.jpg) T Title: PDM Modulator and Sequencer finished Post by: W1IA 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: (http://home.comcast.net/~k1jj/wsb/media/254120/site1071.jpg) Dig the craters: (http://home.comcast.net/~k1jj/wsb/media/254120/site1072.jpg) T Yup....it G's board....he did a super job on it! Title: PDM Modulator and Sequencer finished Post by: W1UJR 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 Title: PDM Modulator and Sequencer finished Post by: W1IA 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 Title: PDM Modulator and Sequencer finished Post by: WA1GFZ 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?????
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 Title: PDM Modulator and Sequencer finished Post by: Vortex Joe - N3IBX on March 02, 2005, 09:12:02 AM Definitely a FB job OM!
Title: PDM Modulator and Sequencer finished Post by: WA1GFZ on March 02, 2005, 09:15:24 AM Joe,
I agree in TX mode but not RX. Try it you will like it. Title: PDM Modulator and Sequencer finished Post by: Vortex Joe - N3IBX 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! Title: PDM Modulator and Sequencer finished Post by: K1JJ 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 Title: PDM Modulator and Sequencer finished Post by: xe1yzy 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 Title: PDM Modulator and Sequencer finished Post by: W1IA 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 Title: PDM Modulator and Sequencer finished Post by: xe1yzy 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 ! Title: PDM Modulator and Sequencer finished Post by: Bill, KD0HG 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. Title: PDM Modulator and Sequencer finished Post by: W1IA 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 Title: PDM Modulator and Sequencer finished Post by: Glenn K2KL 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. Title: PDM Modulator and Sequencer finished Post by: W1IA 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 |