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PostPosted: Feb Tue 16, 2010 8:08 pm 
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Curt,
If you look at the schematic in the first post you'll notice the RFC's are on either side of the crystal that feed either grid and both RFC's go to GND. Shouldn't be a problem since they are operating 180* out of phase.

John


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PostPosted: Feb Tue 16, 2010 8:26 pm 
Silent Key

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Location: Sandpoint, IDAHO 83864
OK. I did not go back to the original post which was made some time ago. In a circuit like that, the crystal is supposed to maintain the frequency of a free running oscillator. Depending on a lot of conditions, it sometimes does a better job of doing it than with other layouts. It is still a good design, however, IF you have good crystals.
Curt

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(Connoisseur of the cold 807) CW forever!


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PostPosted: Feb Tue 16, 2010 11:54 pm 
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You will probably be totally ignored on 160 after dark as that area (typically 1812-1830) is the CW DX battleground. You may have some luck 1800-1810 but Ive rarely heard anything there except in a contest.

Carl


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PostPosted: Feb Wed 17, 2010 12:04 am 
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Carl,
Tha's what I'm finding out so it's 1810 for the next xtal. I'm sure they can hear me because they are real strong on my end. Not at all like 40 & 30 mtrs, usually someone will respond to my CQ and tolerate my slow speed CW.

I do have a couple xtals at 184x & 185x but I'm hearing SSB in that range on up.


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PostPosted: Mar Fri 12, 2010 2:29 am 
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Ok, reworked the Breadboard PP TX and changed the tube from the RK34 to a 6A6 as in the original drawing.

Success! I can get 10 watts out on 160 - 40 mtrs and it's real easy on the crystals too. Found that a loose coupled tank circuit works the best. You can see in the photo where the link was left after testing on 80 mtrs. When coupled right, the current drops and the power goes up.

Was going to put it on the air but couldn't get the antenna to tune up. Went outside to see if something was wrong and found one end on the ground, it's a dipole. The wind has been blowing here for the last couple days with some strong gusts. When it warms up a little and the wind dies, I'll put the antenna back up.

Here is the finished transmitter.

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The Doerle Signal Gripper and the Jones PP TX look good togther too.

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With 40 mtr coil and crystal.

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PostPosted: Mar Mon 15, 2010 11:05 pm 
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Location: Eureka, CA, USA
Now I know what "I got a Jones" means, hihi!

Fabulous work, John! Wish I could just "whip one of those out" in an evening!

Still banging away on 3955 w/my 1944 6L6. Listen for me on 40, 20, and 10 until I get the low pass filter built, heehee!

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Jim Falls
K6FWT
Eureka, CA


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PostPosted: Mar Mon 15, 2010 11:28 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
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Location: Sandpoint, IDAHO 83864
Banging away on 3955? I bet you are raising the irks of some slopbucket operators! HI! Kinds of remind me of some of the things Blackie, W6HLH, used to do when he was alive. Heck, who cares about a low pass filter nowadays? I bet there are more QRM producing devices in a modern home than any "lone 6L6" is going to cause, interference wise.

But to John- To me there is nothing relating to radio that is more beautiful to my eyes than a symetical push-pull circuit using big shiny center tapped coils and a swinging link mounted above a nice dual section variable tuning capacitor.

If I had a rig like that, it would never get operated. I would simply spend all my time admiring it.
Curt

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(Connoisseur of the cold 807) CW forever!


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PostPosted: Mar Tue 16, 2010 12:18 am 
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Jim,
I'm sure you ment 3550 kc.

I got my antenna back up in the air yeaterday and made a contact on 40 mtrs, 7110 kc, in to Nevada.

Will be listening for ya Jim.

Curt,
I agree, the syemmtry of these simple PP transmitters is very nice. Alot like a two step regen.

Ya know, there are only nine parts in this circuit counting the crystal and meter! You can't get any simpler then that!

I pulled out a power suppy I made a few years ago for my Jones Regenrative Oscillator, aka, single tube power oscillator using a #47 tube. I switched the tube in the PP rig to a 53 and wired the supply up. Works just as good as the 6A6. It should since they are the same tube, just different filament voltage.

I tried a NOS RCA #53 that worked great then I put a used Syvania #53 in and powered it up only to get a bang and blue flash from the tube. The darn thing shorted inside so in the trash it went. No wonder it was pulled.

I'm wondering if a PP osc followed by a PP amp is in the future? Wouldn't that be a PP MOPA?

John


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PostPosted: Mar Tue 16, 2010 12:28 am 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
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Location: Sandpoint, IDAHO 83864
Yep it would be a PP MOPA, but for the most part the PP part would be simply dropped. It still would be a Master Oscillator Power Amplifier rig.

You want to know what would look really neat and maybe give you 50 to maybe 80 watts output?

Find a couple of 3C24/24G tubes and put them in push-pull on another board and then stack the two chassis like a rack and panel setup. You will not need any lamp to operate by with the filament glow off two white hot filaments these tubes have. Taht would be cuter than a bug's ear!
Curt

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(Connoisseur of the cold 807) CW forever!


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PostPosted: Mar Tue 16, 2010 12:41 am 
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Curt,
The 3C24 takes up to 2000 v on the plate!

Hmm, what tubes require 1kv or less that will get me 50 watts?

How about a pair of #46 tubes in triode config? I have the tubes and they are the older globe shape. Yeah, and they can be on the top tier for the rack!


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PostPosted: Mar Tue 16, 2010 12:53 am 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
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Location: Sandpoint, IDAHO 83864
Just because a tube will take 2kv, does not mean it has to be operated at such high voltages. I once upon a time had the Eg/Ip curves that were printed on a piece of paper and included in the box containing one of these tubes. I seem to recall they would draw plenty of plate current with as low as 350 volts on them, and maybe even less. The only limiting factor would be the plate dissapation rating.
Curt

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(Connoisseur of the cold 807) CW forever!


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