The AM Forum

Time to celebrate!  The Class E rig is cooking!

Here's the building/construction thread. It has 11 pages of building and construction info:
http://amfone.net/Amforum/index.php?topic=23354.0


Click on this link to see Rico Suave himself:
http://www.youtube.com/watch?v=xeX9zoWSut8

The time has come - I rolled Rico into the corner and now it's time to operate. Last steps - I've installed the temperature triggered cooling system, debugged the VFO and got the rig running reasonably stable and quiet.  The hum is finally gone as far as I can tell.

I've rewired the station audio chain and now have all balanced cables throughout. This definately reduced the hum level to a minimal point to all rigs.

The rig is pictured keyed up into a dummy load at 375 watts full strap. (except for pic #1) Notice the temp gauge that shows the current temp (top number) and the fan trigger temp. (lower number)  The fan is running at the time of the pics.  The VFO is sitting on about 3890.  I lit the analog meters with blue lights.  Also notice the blue digital meters for total voltage and current - and voltage on the RF deck.

Getting the temp gauge, digital meters and freq counter stable during RF key up was difficult. It tooks lots of bypassing and ferrites to calm the digital readings down. They are rock solid now.

Full digital drive using a low level analog homebrew VFO.

There's a few more things I want to add, but Rico is essentially completed. He's easily the best sounding rig I've built to date. Class E is alien technology - with shark fin audio... ;D

T

More:

More:


First pic:  The bypassing, shielding and ferrites required to make the VFO clean was quite a job!


Second pic:  The PDM gen board, Overload board, sequencer board associated circuits. Each required its own bypassing.

Nice work, Tom. Really nice.

Are those Datel digital meters in the rig?

ldb
K5WLF

Vy nice OM!

You did, however, spell "Coarse" wrong  ;D

Nah, that means "Of course it's tuning. What did you think it was doing?" <BG>

ldb
K5WLF

Nice Job Tom!
Looking forward to hearing it in its finished form.

Brent

It sounds as good as it looks too! I like your modular assembly, should be easy to keep this guy up and running, even several years from now when you look under the hood and start thinking, "What the heck did I do here?"

Just one suggestion:  Please don't operate on the displayed frequency because it might make it difficult to hear all those important AARA bulletins!

Thanks for the comments guys. Nothing better than having like-minded enthusiasts look over your projects and kick the tires a little..

Idb:  The blue digital meters are from China and cost about $10 each. Look in the previous 24 pill thread on the first page for more details. They are all over e-bay listed under "digital meters."  I found the accuracy poor and needed to add my own shunt or voltage dividers. They are also prone to RF, but settled down with bypassing and ferrites. Analog are better, but digital looks cool for a few meters on the rig.

Johnny: heheheh..I should have used fast and slow - easier to spell. That will be corrected soon, though every rig needs one obvious JSment.


Rob - You noticed I intentionally used 3890. The reason is cuz once in a great while I'll forget to switch on the dummy load and instead transmit into the antenna for a test. This was the safest way of not bothereing anyone if I did... ;D  Yes, I kept everything modular - and in fact I didn't bind all the wires in tie wraps as usual cuz I want to be able to get in there and service it. It's real easy to work on everything now, so why not keep it a little ragged looking in favor of access?

Tina - Hope to catch you on this weekend for some more tests. I still need to verify the key-up pulse is gone, hum is gone and the VFO has little to no shift/phase shift. Gonna take Yaz sailing all day one day this weekend, so will see ya at night.

BTW, looking at Rico, the pictures don't do him justice. He's so much prettier in person.. ;) I'm on the fence of whether to add another 24 pills or not. I'm running out of room - don't want to make it a crowded mess..  Maybe I'll leave him as-is until Tina straps me with HIS 48 piller..

T

and dont forget to play the theme video. put's you in the right mood.

http://www.youtube.com/watch?v=xeX9zoWSut8

HAHAHAHA!!    You're right, Derb.  Click on this link first and then view the E-rig Rico pitures. It adds some class... ;D


T

With all of that blue it seems like you're trying to TUBERIZE your rig. ie glow from 872's or 866's.
But it's really first class
I'll have to listen to the audio.

Fred

Tom:

Excellent!

Lookin' forward to hearing it.

Now you need to upgrade your audio processing to match the quality of that station on your frequency ;-)

Dan

10 dB worth of work for 3 dB of signal  ;D

Very nice looking rig. High Style! I am certainly impressed with that and more so with the engineering. I just can't get into the video though haha Spanish dance rap and sharp pointy boots R not my style! But if I hear certain incidental music in true High fidelity I'll know where it came from.

Tom, love your work and never ending enthusiasm :) That's where it ends ;D ;D The only thing that had me hanging in there in that video was the female dancers ;D ;D

Your scene of humor kills me ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

After a full day of debugging the new 24 Pill digi rig, She's on the air at full strap!!
YAY!! ;D  I will update with pics tomorrow....I'm toast...started at 7:00 A.M. this morning to put the last push to finish. Yapping on the air now!

Brent
W1IA

46 at 34 not bad Tom Vu.

Thanks for the comments, guys!

Johnny - your remark about "10db of work for 3db more signal" has become a local mantra... ;D  Too true. Though both Tina and I are still considering it, I may stay with what I have. It's too nice a rig to screw up at this point.


Lately Brent and I have been on comparing notes with his almost identical 24 piller. (in basic design)  Tina's rig is sounding really FB since he added some more deep lows last night.


Terry - Yes the Rico Suave video is so corny that it's funny. The Derb picked a good one.


Rico has run a few nights now with heatsink temps getting up to 110F at times. No problems or crap-outs. Though I plan to order some more ferrite beads to sprinkle around on various leads. I am still getting some slight variation in the digital meters on key up, but almost gone. The ferrite beads help a lot. I need to add some to the ac lines.

I had some breath pops lately and added a foam cover to the RE-20 last night. That seems to have helped. Because the E-rig will permit a deeper low end boost, it showed up -  I never had that problem with Fabio.


There is a very noticable difference in less summertime shack heat when running Rico vs: Fabio, the 4X1 AM rig.

T

Better is often the enemy of good enough

The nail that sticks up gets hammered down

Oh, I gotta million of 'em  ;D

Looks and SOUNDS good !

I guess there are 4 of these rigs on the air (24 pills);  K1JJ, W1IA, K1KBW and WA1QIX.  All are essentially the same design, but the implementations are all rather unique. 

There are two others lurking out there - KE1GF has one and there is someone else whom I cannot recall. 

Frank WA1GFZ has a similarly powered RF amplifier that has only seen the light of day ONCE at my shack during a test run (hint hint, Frank  ;D  )  There's at least one more in incubation up in Concord, NH - but the gestation period in that part of the world, at least for transmitters can be lengthly  ;)  (another hint!).

This is the one I built.  Not as pretty as Rico, but what the heck  :D
(http://www.classeradio.com/1kw.jpg)

Last winter Tom Vu kicked my butt over crappy audio not it is Steve's turn.
(keep up the pressure) The QEX article was Nov. 05 and the modulator chassis has been done for 2 years. Power supply is almost done.
ABFT to do it.

Same package with different interior.

A couple more of finished 24 Pill digi drive rig

You guys make it look easy  ;)   
                                 Very nice beasties.
                                                   DJ

I'm not sure if difficult applies to construction so much as persistence. They take time DJ.....If I can build it anyone can! :P Jump in..the waters fine ;)
As JN has coined 10db of work  for 3db of gain HA ;)! ;D ;D

Brent
W1IA

These transmitters are relatively cookbook IF YOU FOLLOW THE RECIPE  ;D  There are a few absolutes that must be followed (like any transmitter project), and outside of these, it's all personal preference.

If you more or less stick to the RF layout, and TEST TEST TEST every stage along the way to find your mistakes (and we all make them - I sure do) and verify proper operation of every stage before applying [with your variac] one volt of DC to the RF amplifier, you will have a successful project  8)

Yep, I agree that modular building and testing is the best way to go.

Also, we need to lay everything out so it is later accessible for repairs and modifications. I have seen a few rigs (including my own earlier e-rig) that was extremely difficult to work on. The ideal situation would probably be pull-out drawers. This time around I didn't even bother to tie wrap the wire harnesses. Anal wiring just leads to difficulty tracing and troubleshooting later on. I want my rig to be EASY to work on.  'Nuff said.

The latest E-rig innovation, digital drive, (with the homebrew analog VFO) is a nice addition. It's a more stable and reliable design. With this self-contained low level driver, there's no worry of blowing out the fets with a ricebox driver anymore - plus QSYing is a breeze without retuning the gate drive and worrying about imbalances, etc..

Looks like you have lots of room in there, Tina. I can see how it wud be easy to expand later on... ;D   You even left on that $25 price tag in pic #3. I guess it doesn't cost "only $20 and a handful of Fets" to build a class E rig anymore...

T

Inflation!  Why, if we keep printing money the way we are it will soon be $100 and a handful of FETs  ;D