50l6 Tube CW Transmitter

I know this is late - but the 6L6 transmitter is the same as the 50L6 except for the filament voltage. Do a google for "6L6 Transmitter". 50L6 = 50 volts filament voltage. The 50L6 is a beam power amplifier. I'm gonna watch the homebrew section jest so we can :bdh: do it the old way. I like the old skool way. If I can help - just ax....I do toobs. Rumrunner

I have one I built years ago. I never used it but dug it out 2 days ago and plugged it in. It actually works and pumped out just over 5 watts into my dummy load. (It burned out my loop lamp absorbtion meter like just "poof".)
I dont remember where i got my schematic from. There is however one on qsl .net. Search 50L6 CW transmittter.
Mine is ac dc design. I can hear a bit of 60 cycle when monitering it when loaded up on the dummy load. I dont now what it sound like on air. I used a tiny Tv crystal for 80 meters. I believe the crystal is heating and it drifts a couple of KCs on keying. Probably the tiny late style crystal is a bit light in construction for a old tube circuit. I have read some hams put a light in series to limit curent and heating. I may try that today. I normally am a 20 meter guy so i will have to hang some wire before i try it. I have another 50l6 and may make a regen with it so i have a pairiwith a common power supply. I wound my coil on I think a wax paper roll and then wound the coupling ant coil over that. I am quite frankly surprised at the power and how it actually works. I have been a sleeping ham for a few years and this old stuff has rekindled my interest. I have sitting here right now that transmitter , a 6sl6 regen on battery power and a 245 TNT battery powered transmitter. (on 40)I may change the TNT to TGTP just so i can move around a bit. I want to put a small cap on the 50l6 transmitter too to rubber the crystal a bit for more flexibilty. I wonder how it would work with a TGTP set up.
Don
VE3LYX

You can 'rubber' a crystal several ways! 'Comet'/'Ajax' cleansers were one, a graphite pencil another. Metal 'can' crystals were a real PITA, but the '243'(?) cased ones were easier. Ah! Those were the days, right? Don't know about you, but I'm glad they're gone! LOL
- 'Doc

The 50l6 transmitter is to the left of my regen set. It has the single knob but matching finish. West of that (the regen in the middle) you can just see the 245 TNT I just built .
Don
VE3LYX

I tried it today. Lot of hum on the signal. more than I would like. ALso chirps, not bad but it becomes less as you use it. I think the crystal, a small one, is getting warmer than it should. I read somewhere you could put a resistor in series with no ill effect to cure that. Mine is line powered with no transformer. It tunes well or very distinctly. Power output on the watt meter seems high to me. I am trying to sort it out. I checked it with a receiver in the far part of the house. Other than hum it is clean meaning it is transmitting where it is suppposed to be and nowhere else (always good!) I may rebuild it. I think i could do a better job now. I probably made it 15 or 20 years ago now that I really think about it. I whipped up a makeshift wire antenna. SWR isnt wonderful but less that 1.5 to 1 . The hum bothers me the most. I tried a different power supply but it was as bad. I may seperate the PS from the RFcircuits. I have to confess though I am surpised that it actually works. If I knew when the colurburst guys were on 80M and I had one ot too far away i would try iit to see how it sounds from a distance.
Any suggestions of cleaning up the 60 PS noise would be appreciated.
Don VE3LYX

I have it working. Set the receiver in the bedroom at 3.580,3 and chirp is gone as is the 60 cycle hum. I changed two grounds around and eliminated one wire which may have been acting like an antenna for the 60 cycle hum. Now I need an on the air test with another ham.The meter says around 10 watts key down. I doubt that. Seems too optimistic to me. It did smoke my Rf indicator bulb though so it has more than my 40 meter battery powered one does. Am anxious for an all glowbug QSO. My code is rusty but is will come back. I am going to check out that timer 555 deal now. thanks
Here are Pics of my 50L6 TX , my regen and the whole ring dang doo.
Don VE3LYX

50L6 transmitter revisited.

I have been working on my 50L6 transmitter. It appears to be a decent working unit. As I said I changed some of the grounds slightly and got the hum down to acceptable levels. (goes "beep" in stead of BEZEZEZEZEZP)Today I moved the crystal and some of the wiring away from the integral transformerless power supply/votage doubler. I also put a 70 ohm resistor in series with the crystal as it seemed to heat up enough for a slight chirp when cold although to be truthfull once you were pounding brass it settled in and stayed good. It didnt suffer any from the modes that is for sure. Seems better now. Power according to my Realistic SWR/ Modulation/ Watt meter is showing a solid 15 watts. I guess techncally that is not QRP anymore but in todays world of power dimming linears it is nothing. Today I also rubbered the crystal. I had two 30 uufd caps so i jury rigged one and tried to see if it would pull the crystal. It does nicely. I will try two tomorrow to see how that works. It just gives me a bit more flexibilty as I can wiggle a bit rather than being totally rockbound. If the two works then I will get a DTSP switch so "up" will be one cap, "off" will be no cap and "down" will be both caps. I have yet to make a contact but I did some field testing today with a portable reciever . It is getting out and is strong and not dirty either. I guess I need someone not too faraway maybe to verify it is making it out of this county but I think it is. It will blank the portable receiver a mile away on freq. I have been practicing my CW too with W1AW which is nice since I dont have to retune the receiver afterwards but just wait till they are finished for the day. A friend gave me that key in the photo. He found it at the dump. I have it cleaned up and working but it is different than I am used to. I am getting the hang of it, finally. So if anyone would be so inclined to listen for it I call on the colourburst crystal freq from noon on (on the 1/2 hour) as long as it is not being used. When I get my first regen and 50l6 QSO I may panic a bit but I sure am having fun playing with this thing.
Don VE3LYX

Glowbug QSOs

Just an update to report I have had some successful glowbug QSOs using my one tube regen rx and my 50l6 tx. It works very well, Yesterday I made a X-tal spotter for my rx. I take the X-tal I am going to use in the TX, put it in my Xtal spotter. Press the button and tune the regen from that signal . I install the X-tal in my tx and I am in business. Spotter uses a 7400 chip, two caps and three resitors.
Don VE3LYX

6 years later, Transmitter still working well. I used it a few weeks ago in the NRR event. Look for me around 3555 usually.