Totem-Pole Progress Report

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DDS Kit Packaged

Postby ke1gf » Thu Jul 15, 2004 11:27 pm

I finally packaged up the DDS kit so that I could use it someplace other than the bench...

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what do you guys think? Better than a Shady-O-Rack box?
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Postby steve_qix » Mon Jul 19, 2004 9:12 pm

Hi Bill,

Looks really nice! Just got back from Niagara Falls and Canada.

Wow, is it nice in that part of Canada!

Regards,

Steve
Visit the class E web site at:

http://www.classeradio.com
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Postby ke1gf » Mon Jul 19, 2004 10:05 pm

Thanks Steve, things are comming along nicely.

Hope to hear you on the air soon.


I posted this picture to amfone.net BB a few days ago.

Image

-Bill
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Analog Devices DDS paper on da web.

Postby W1DAN » Thu Aug 05, 2004 4:52 pm

FYI...

http://www.analog.com/library/analogDia ... 8/dds.html

also available as PDF file...dds.pdf

73
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Postby W2INR » Wed Aug 25, 2004 9:37 am

Whats the progress report on the DDS.

I think I would like to incorporate this into the E Class project here Bill.
G

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Postby ke1gf » Fri Aug 27, 2004 10:05 pm

G' everything looks good except for one thing.

I almost had a company setup a small quantities mouser number for a packaged 5x7 SMC crystal osc (in 14 DIP) to drive the DDS. But S#!T happened.

A low jitter OSC is very important. Especially at full strap.

Turns out that once they packaged and tested my initial order the yeild was something like ~=60% usuable parts, They shiped to me what worked and told me not to ask for anymore.

I only have a few here and I have a gut feeling that the MTBF of the ones I have isn't too good. We'll see.

I'm back in school so I don't have endless hours for seaching through data-sheets.

Here's the spec of my OSC:

3rd or 5th overtone, I'm confused
I wouldn't use an OSC with any type of internal multiplication.
5V HCMOS outpoot
x < .5pS MAX RMS jitter
x < 30pS MAX P-t-P jitter
x < 25PPM -40C/+85C
14DIP Package
150 - 180MHz is the freq band
anything less than 150Mhz the output will be less than desireable
anything more than 180Mhz the chip will burn up.

Frank?

I still haven't had a trained tech put this thing on a S.A. so I have no idea how good the output is.

kind of like 3 day old sushi: looks good, smells good?

Looks like the way to go at the moment is to drive your 4 driver fets (single ended) with my totem-pole driver.

I don't have a sophisticated enough driver board to drive 4 modules directly.

It seems as if a single-ended driver is easy enough.

This weekend seems rather leasurely shool wize so I'm probably going to setup my big rig with the VFO in the configuration as stated above.

The VFO only puts out ~= 10mW, a Broad-Band IPA from Communications Concepts biased into Class-C is an option.

Best,
-Bill
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Postby ke1gf » Sat Aug 28, 2004 11:55 am

This is a good IPA if you don't want to do the totem-pole thing.

http://www.communication-concepts.com/an779h.htm

-Bill
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Postby frank carcia » Mon Aug 30, 2004 7:02 am

Bill,
The CCI IPA is biased class A so it will ned plenty of heat sink. Pete
WA1SOV bought one and blew the output stage. I think he reduced the bias a bit. I like seeing you print oscillator specs because now you understand the problem. You could check spurs with a good RX with a tight filter. I'm not sure the R390A has enough dynamic range. If I hear you on the air I will fire up my Racal with the 50 Hz. filter.
Finished 1 side of the new qth yesterday. 3 more square to go then soffets. Hardware arrived for new modulator. It won't be long now till I can play radio and too broke to continue building this season.
Good Luck with school! fc
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Postby ke1gf » Mon Aug 30, 2004 7:54 am

Frank, thanks for your input.

-Bill
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Postby ke1gf » Mon Aug 30, 2004 6:48 pm

This is my TP driver for a single ended Class-E rig... Maybe this weekend I'll put it in.

Image

-Bill
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Postby frank carcia » Tue Aug 31, 2004 7:03 am

Bill,
What are the FETs you have mounted on the board?? fc
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Postby ke1gf » Tue Aug 31, 2004 4:11 pm

Frank the big fets are FQA11N90's and the small fets are a single IRF610 and 2 IRF9610's I suppose instead of using 2 9610's a single 9510 would work...

-Bill
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Postby frank carcia » Tue Aug 31, 2004 7:28 pm

Very good I used 9610s and 710s in mine. I like your layout. I hard wired mine on a angle bracket. Then I added a second stage with 9660 / 740 if I remember.
I think wiring inductance limits performance.
Heat sinking doesn't appear to be a big issue here.
It looks like I should finish siding by Oct so can't wait to get back in the shack. 2 1/2 square and 84 feet of soffit to go.
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Postby ke1gf » Sat Sep 04, 2004 4:42 pm

Hey All, How's it going? I had to scrap the design shown above... this is the new design:

Image

Anyway, it looks good, I had to stop testing; my dummy load was smoking. I put some audio to the rig @ 1kw seems to be working just as well as if I were driving it with a rice box.

Image

Catch you on 75, gotta run supper time and must go visit Nana.

All the Best,
-Bill 'GF
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Postby ke1gf » Sat Sep 04, 2004 10:23 pm

Well things worked out well with the latest design, I'm having a great night on 75.

-Bill
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