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Author Topic: Does anyone run hollow state QRP?  (Read 8594 times)
KM1H
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Posts: 2502




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« on: August 05, 2017, 08:03:44 AM »

My primary RX is a 1931 National SW-58 regen when on 10-12M, a 1934 National FB-XA superhet, and a 1934 designed WW2 Andrea (RCA) RAL-7 which is also a regen.

The TX is the external VFO from a pre WW2 US Army Meissner 150B which came with a full set of coils and runs 4-5W from a 6F6.

All CW of course and the above is responsible for most of my 9 band DXCC.

And yes I also have a modern station Grin

Carl
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N0YXB
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Posts: 1122




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« Reply #1 on: August 05, 2017, 11:34:08 AM »

My primary RX is a 1931 National SW-58 regen when on 10-12M, a 1934 National FB-XA superhet, and a 1934 designed WW2 Andrea (RCA) RAL-7 which is also a regen.

The TX is the external VFO from a pre WW2 US Army Meissner 150B which came with a full set of coils and runs 4-5W from a 6F6.

All CW of course and the above is responsible for most of my 9 band DXCC.

Very cool, and impressive!
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AK0B
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Posts: 267




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« Reply #2 on: August 05, 2017, 12:54:14 PM »

I sometimes run a 6J6 single tube oscillator on 30 meters.   If you google QRP transmitters when the group of qrp rigs pop up the single tube in a gray box is my 6J6 transmitter. 

de stan ak0b
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ONAIR
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Posts: 3526




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« Reply #3 on: August 05, 2017, 01:42:08 PM »

A true time machine!!   Smiley
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W1JKA
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Posts: 2086




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« Reply #4 on: August 06, 2017, 08:56:22 AM »

Semantics: 2-5 watts CW/DX is my niche with my K1 and MFG Cubs but if you consider anything under the 100 watt controversy as QRP I often run my Johnson Adventurer tube xtmr. along with my FRG 7700 as my rcvr.
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KC4ZGP
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Posts: 1637




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« Reply #5 on: August 06, 2017, 05:41:37 PM »


1934? Wow that's about when Marconi invented radio in  St. Louis.

What is your antenna?

So if something breaks there's no mystery eh?

And I'll bet the schematics make sense.

This new-fangled stuff works fine until...I don't even want to think about it.

Kraus







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AE0Q
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Posts: 64


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« Reply #6 on: August 07, 2017, 07:57:41 AM »

I first discovered QRP when I was playing with my keyer with my Johnson Ranger-2 in standby.  A ham 6 miles away in St Paul heard me and replied.  He had a Ranger, too, we found they put out about 200 mw just keying the oscillator.  I imagine a lot of older tube transmitters could do the same.  Not very efficient, though :-)  I soon got a Ten Tec PM-3A, used it from the barracks in Navy schools...

Glenn AE0Q
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Glenn and V-NATCH Katie,
HP-O, MXB, MJB, XF
http://www.hoopsandjumps.com/
http://funagility.webs.com/
N2DTS
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Posts: 736




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« Reply #7 on: August 14, 2017, 10:37:24 AM »

I used to do it with a homebrew single 6146 rig.
I am thinking of building a 2E26 rig with a homebrew vfo setup.
The VFO's I built for the AM transmitters seem to work well enough for CW.

Here is one I built before I added the digital freq display (counter):


Here is another one before scrapping the pto and putting in a regular coil and cap VFO:


Both still in use.

Something smaller and table top would be fun, remote the power supply....


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KD8IIC
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Posts: 648




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« Reply #8 on: August 15, 2017, 08:22:54 AM »

I run a single 50c5 tube and xtal rig that my good friend Jim, KK4GFR, built for me. He calls it a DX-5.
It's a real beauty and performs well with clean chirp free keying. Fully 5 watts output on 40 es 80m.
Thanks again Jim! 
VY 73 from lane de n8aft  sk  ..
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KM1H
Member

Posts: 2502




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« Reply #9 on: August 16, 2017, 01:35:38 PM »

1934? Wow that's about when Marconi invented radio in  St. Louis.

What is your antenna?

So if something breaks there's no mystery eh?

And I'll bet the schematics make sense.

This new-fangled stuff works fine until...I don't even want to think about it.

Kraus


I started my ham career in 55 with homebrew and worked my way up from there.
The USN taught me how to really understand electronics and I made it a career until retiring in 2002.

A 1963-69 stint at National Radio as service tech, service manager and R&D tech was the best job I ever had as every day was in learning mode.

My antennas vary but many tall and BIG ones have been used during my full bore contest days. How does a 4/4 KLM on 40 sound?  Grin Roll Eyes
A hilltop location on 5 acres since 1989 sure helps and the long boom 4/4/4/4 stacks (all homebrew) on 20-10 are long gone.

Currently use wires and verticals on 160-30, 3 el on 20 and 17, and 4 el on 12 and 10. All homebrew. Thinking about a new 6 el on 36' boom for 10 to make my own propagation as I love to play with AM there.

Also have HB verticals with elevated radials 20/17, and 15/12/10 for the vintage tube stations since they are not close to the rotator controls at the modern gear bench.

Carl


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KD8IIC
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Posts: 648




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« Reply #10 on: September 07, 2017, 01:49:16 AM »

  I've been known to turn down my Viking II to 5 watts out on 80. Same with the CE-100v and Ranger.
  Who ever said you need to run a pint sized rig to do QRP?
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AE7TE
Member

Posts: 55




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« Reply #11 on: October 18, 2017, 01:05:18 AM »

Not yet, but it's definitely something I always wanted to do.

I've built quite a few tube regenerative receivers. Most of these were at lower plate voltages, but I'd like to get my hands on a low-wattage transformer capable of powering a decent four or five-tube superhet of my own design. Problem is band-switching. I'd have to figure that out somehow.

I'd like to start out small-ish, like having a two-tube transmitter. I'm not going to spend lots of money accumulating FT-243 crystals, so I'll most likely design the first tube to amplify the output of a digital VFO or crystal oscillator. Then it will assault the grid of the final, which might be something like a 2E26, 6L6, or a sweep tube. Once I've secured a nice high-voltage power supply, I'll look into this further.

I've also wanted to make a transmitter capable of screen modulation for AM. I like the idea of running AM, even if it's from a small mobile rig in the vehicle.

Ed AE7TE
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N3HEE
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Posts: 433


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« Reply #12 on: October 18, 2017, 04:49:51 AM »

I built a single 6L6 transmitter on a pine board.  I can drive it with a crystal or a homebrew DDS VFO.  It uses plug in coils and works great on 160-40 meters.  About 5W output with about 250 VDC on the plate.  Uses a HeathKit HP32A power supply.  I also have a modified HW-16 that can be turned down to under 5 watts.  The HW-16 was my first rig as a novice back in 1976.  I made thousands of CW contacts on that rig ! 
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Joe
N3HEE
CW Academy Advisor (Level II)
W3TTT
Member

Posts: 267




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« Reply #13 on: October 18, 2017, 01:10:18 PM »

I also have a modified HW-16 that can be turned down to under 5 watts. 

I just acquired an HW-16.  Could you point me in the direction of how the modification was done to turn down the power?
thanks
Joe
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N3HEE
Member

Posts: 433


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« Reply #14 on: October 19, 2017, 06:41:28 AM »

Joe.  

From Ken Gordon W7EKB....

The original way to adjust the RF power is by varying the B+ to the
screen of V9 the PA. This does not give you very much range, and
does not work well.

If you wish to fix this problem, disconnect and solder the wires from
points 2 and 3 of the R13 power level pot together and insulate the
ends with shrink-tubing, then tuck out of the way somewhere safe.
This connects full screen voltage to V9, the PA, and it will now
operate at full power at all times.

Disconnect the wire from the B+ buss which connects to R6, a 22K
2W resistor which is the screen voltage feed to V6 the 6CL6 driver
tube. Connect this B+ buss wire you removed from R6 to point 3 of
the Power Level Pot. Connect a wire from point 2 of the power level
pot back to R6.

This duplicates the power control, but it is now attached to the
driver. Power output can now be adjusted from full power down to
about 2 or 3 watts.

If you increase the value of R-14 you can adjust power down into the
milliwatt range and still go up to full power with a twist of a knob.
You will have to experiment with the value of R-14 until you get what
you want.

I (N3HEE) replaced R14 with 2.2K 2W resistor to obtain QRPp power levels with power level control.  

Also see my (N3HEE) QRZ page for other mods I made to improve the HW-16.

More mods here from Ken Gordon W7EKB .....

https://puck.nether.net/pipermail/heath/2012-February/038573.html
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Joe
N3HEE
CW Academy Advisor (Level II)
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