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Heresy follows Re: [QRPLabs] IRF510 #alignment #magic of hollow state #alignment #magic


David Wilcox
 

But even the new comers to this hobby should have at least ONE tube based rig. There is something special seeing a filament light up and even hearing the crackle as the audio starts. There is magic in tube rigs. With solid state there is only SMOKE or NO SMOKE and the rig either works or it doesn’t. I keep a Drake 2B on my bench and turn it on periodically just for the “joy”. Even today I enjoy the smell and the mental picture that comes in my mind of days gone by whenever I start to solder a part into a circuit.

Dave K8WPE

David J. Wilcox K8WPE’s iPad

On May 27, 2020, at 8:53 AM, James Daldry W4JED <jim@jimdaldry.com> wrote:

Hi, Brad

If I made a "set of boots" using one of the Loktal tubes I wouldn't make it a permanent attachment to the QCX, because Loktals were good up into VHF (little skinny pins) so it could be used to protect the Baofeng, at least on 2.

73

Jim W4JED

On 5/26/20 9:25 PM, Brad Thompson wrote:
Bill Cromwell wrote on 5/26/2020 6:40 PM:

Hi Gwen,

On another QRP list I make comments a couple of times per month about adding tubes to QRP projects. The fact is I used a 6146 as boots for an Argonaut 509 (once upon a time) when more power was needed. And yes to the sweep tubes. There are large sweep tubes and small sweep tubes. In fact there are audio output tubes that have done nicely as the finals in RF transmitters and those come in 'sizes' too. I play with some tubes to this day. They still do what they have always done. Some hams have even built rf stages with Nixie tubes!
Hello, Bill and the group----

Nixie tubes as finals-- I'd like to see how it's done.

Heresy follows.

Please don't read further if you have a mouthful of any beverage.

Caveats: I haven't assembled a QCX, nor have I thought through the
practicalities of the following proposal. What follows is an exercise in handwaving.

Based on the number of damaged output MOSFET accounts, maybe it's time to
interpose a linear buffer amplifier between the QCX and the unruly world of antennas.

In keeping with the QRP ethos, I'm imagining an add-on outboard linear amplifier built around
one or two vacuum tubes as designed for battery-powered radios of the 1950s.

(Pause to allow readers to dry their keyboards).

Dave Schmarder of Dave's Homemade Radios shows a two-tube regen design featuring a 1T4 untuned RF
stage and a 1T4 regen detector:

http://makearadio.com/tube/2-1T4.php

...Throw away the regen part.

Add electronic switching to heat the filament and apply B+ to th tube when the QCX transmits.

Another candidate tube would be the 3A5 dual triode used in a push-pull circuit.

Finally, if anyone might be interested in a grounded-grid(!) linear, there are the
Loktal-based 1LC6 and 1LA6 which have all of their grids brought out to separate
pins (and none returned to the filament as in the 1R5 and 1T4).

I have lost track of the image I have of a uBitX assembled with a pair of vacuum tubes sticking aout of it. It was all show and no go :
See? Someone has already tried this<g>.

Yours for protecting MOSFETs from abusive antennas, and 73--

Brad AA1IP



Bob Benedict, KD8CGH
 

Indeed!
While waiting for the QSX I'm restoring a HW-16 and looking forward to building the QRPARCI 2020 Buildathon GlowBug (PP2) two tube transmitter.
--
  73
    KD8CGH


ajparent1/KB1GMX
 

To that I have: a SX100, Two home brewed tube RX, HW101, Tempo-One,
National NCX-5, Hallicrafters HT37, Siltronix1011C and enough tubes
laying around to make a few rack loads of radios.

I'd love a Drake 2B or 2C, I've fixed a few and they are just interesting radios.  
The only reason I don't is the room is 10x14feet!

I also have a few intermediate age radios like ARS AX190, Tentec Argonaut 505
and Tentec Triton.

I like radios!  I build radios.  Been doing that since the 60s.

Glow in the dark or not, when it emits smoke, you fix it.  
When its working you give it love by running it and enjoy
the sounds and smells.  Its still about the magic of hearing a
voice from across the street or some ocean.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Ted 2E0THH
 

On Fri, May 29, 2020 at 02:15 AM, ajparent1/KB1GMX wrote:
Its still about the magic of hearing a
voice from across the street or some ocean.
Beautifully sums it up Allison. I'm still giddy that this little QCX marvel made it all the way from the UK to Tasmania on WSPR from a dipole atop a 1 metre high beech hedge! It is magic.
My glowing collection involves an Eddystone S556, a Codar TR45 I built as a kit in the '60s and most recently a Trio 9R-59D, I was looking for an oscillator to tune this radio up when I happened upon the QCX.......

73s Ted 
2E0THH


Bob Benedict, KD8CGH
 

I didn't mean to imply that the HW-16 is my only hollow state electronics - just that it's on the bench.
I recreated my '60s novice station with a rare, and weird, Mosley CM-1 receiver, Heathkit DX-60 transmitter, HG-10 VFO and HD-11 Q-multiplier.

--
  73
    KD8CGH