The return of K1JJ

[WA3VJB]

In the WANTED section you will see Tom's disclosure he plans to get BACK ON THE AIR !!

From the looks of things, he's apparently building a QRP mobile rig.

Looking forward to hearing you OM / caw maw

[w3jn]

"Wanted:  3 4X1s or 10,000 50C5s"

GL Tom, bunch of us were talking on the air 'bout how much we miss ya.

[Todd, KA1KAQ]

Having 'JJ back amongst the herd will be HiHiFB indeed. He adds some depth to our childish humor.  

Not to mention a big sig!

[WA1GFZ]

Tom Vu, is getting busy with his business  again but he and I have been doing stealth on air testing of a new machine. He will be back

[Steve - WB3HUZ]

Yes indeed! I want to hear more of this.

http://amfone.net/index.php?ind=media&op=file_view&iden=185

http://amfone.net/index.php?ind=media&op=file_view&iden=223

[WA1GFZ]

BTW Tom Vu found he has a soft 4-1000A and needs one.

[W1RKW]

He said QRP   

QRP_K1JJ = 1kW

Mr. Vu has been providing plenty of advice to me on my 813 rig since it is patterned off his 813 Maul.  I can't say enough thanks for his help and advice over the many months.  He's found the time in between his new business to lend time to exchange emails with me.  My hats off to him.  He's the quintessential elmer and ham.  Looking forward to hearing him on the air with his new rigs and talking to him with my new rig. 

Others who should be thanked as well:  Timtron/HenryLR and Frank/GFZ. Thanks guys. 

Got some bugs to work out but the 813 rig will be spewing AM RF shortly.

Bob

[W3RSW]

Thought I heard '185' on the air 'bout a week ago.  Very entertaining. Original recorded back in Japan, Inc. days?

[K1JJ]

Yo Guys!

HehHeh....all the usual suspects. Yep, I can see it'll be fun getting back on. I missed the action for sure.

I've saved up some good laugh material over the last two years. Even wrote a ham radio game show script that can be held on the air, just like the Limbo "How low can you go" we all used to do on 75M.  The new show is called, "I know how hams think."  Contestants compete and try to anticipate how a ham would respond to a particular situation.  It's all canned questions, but pretty funny. (caw mawn)

Anyway, here's a few shots of the new homebrew 4X1 X 4X1 PDM rig and the 4X1 X 833A's plate modulated rig.  The pdm rig took me a good two months of troubleshooting  get working right. The pdm filters leaked, switch tubes took off, pdm generator was unstable, dud tubes, etc. But now its pretty flat and clean with switching sidebands down at least -110 db.   It's ready to snort fire.  Thanks to Frank/WA1GFZ for his e-mail and phone help. He be da man when it comes to pdm and power supply switching magic and design.

Debugging the 4X1 X 833A's rig was much easier, however. This rig has heavy audio negative feedback for that smooth sound, using 1kw RCA BC iron. I ended up buying a new pair of those wonderful 833C's with the carbon plates for $110 each at RF Parts. Highly recommended. Notice that all rigs are under Plexiglas for our viewing pleasure.


The third new rig not shown is the BLOWN 813 X 813's. This rig is the usual "Tesla 360" design.  The nice feature here is the new WA3KLR designed cathode FET audio driver. It works perfectly and allows up to 10db ++ negative feedback. No transformers, so no neg feedback instability or phase shift. The FET driver burns 5 watts max to drive the 813 modulators to max power. Note: The 813's need about 50 volts POSITIVE  on their grids to allow for big audio peaks. This innovative FET audio driver could be used in place of most tube/xfmr drivers or backwards connected 8 ohm xfmr setups out there, if desired. Most any big or small plate modulated rig with a separate fil transformer for each mod tube will work.

There more stuff to talk about, but we'll save it for on-air.

73,

Tom, K1JJ


*Uploading is slow today, so will post pics as I can *

[K1JJ]

"GirlyMan"  4X1 pdm rig:  (has no BA transformers)

[N1ESE]

"GirlyMan"  4X1 pdm rig:  (has no BA transformers)

Shiznit, that's the biggest QRP rig I've ever seen.   

[W3RSW]

Gorgeous.  -man, look at those coils; what with the price of copper these days, maybe a litle iron wouldn't hurt

Can't wait to hear the beast on the air.

[WA1GFZ]

Those are not slop buckets on top of the rig.

[WA3VJB]

Great googlie mooglie !!!  --Zappa

[W3RSW]

So Babar's mom was REALLY pee o'd when Babar unravelled all the TP rolls in the house....   "But Mom, I NEED them to wind coils for my PDM rig."

[WA1GFZ]

Well, in Tom's case he used sheet-rock mud buckets to deal with the slop buckets....I need to do a couple more to complete the new QTH this spring. We have a special one in the basement my son used early on before we had water. It is marked in bit letters "EPB"
Emergency Pooper Bucket. He only used it a couple times.
Single layer inductor makes the best pdm filter.

[Todd, KA1KAQ]

Hey Frank, I have a stack of those buckets of you need some....

I didn't even notice the inductors atop Tom's rig in the photo until reading Rick's post and looking again. Figured he just stacked some excess stuff up there. Now those are coils!
m

[WA1GFZ]

I need 2 or 3 with mud. SS pdm you can use PVC pipe. I'm working on my SS rig these days. The power supply is about done.

[K1JJ]

"Fabio"   Cuz it's pretty and smells so nice.    4X1 X 833C's

[K1JJ]

Side view of  PDM rig's RF deck (bottom)  and switch tube deck (top)  ...  cut-out normally covered with Plexiglas.  Plug-in coils, vacuum variables, chimneys on all tubes.

[N3WWL]

Can't wait to hear that thing on the air OM.  Perhaps the "lowest voice in America will show up

[ka1bwo]

"Fabio"   Cuz it's pretty and smells so nice.    4X1 X 833C's

LOOOOOOOK AT YOU TOM VU!!!!

[K1JJ]

PDM filter -  1,800 turns of #22 wire wound on THREE 5 gallon plastic pails.....   60 mh and 35 mh coils.....    Switching sidebands now down over -110db. This takes the place of the mod iron, so to speak.  Winding these was a perfect example of, "a mind is a terrible thing to waste."

[N3DRB The Derb]

you gonna be the master with the ghetto blaster.

[steve_qix]

Hi Tom,

Yikes !  Sheilding?  What's that    We don't need no STINKIN' shielding !   

But, seriously, if that rig is anything like my old 4-1000 PWM rig, the modulator will radiate energy like crazy (not to mention the RF amplifier, but that's another story).

There was MOOCHO high frequency RF energy radiated from the PWM filter (the input inductor and associated interconnecting wires were the biggest radiators).  There will also be considerable EM field energy in the vicinity of the PWM filter coils themselves.  I know, call me a worry wart, but I'd be rather concerned about the EM field radiation.  The RF energy radiation will be a TVI/RFI problem, but if you don't have any nearby neighbors, what the heck.  That EM field might be worth checking.

Otherwise, certainly has a "look", that's for sure!    Here's the PWM filter coil from my old vacuum tube PWM rig, and the associated filter for the equiv. solid state rig.