Why not build up the little tube type QRP Transmitter for 40 Meters and 5 Watts out?
Пікірлер: 67
@VintageTechFan4 жыл бұрын
Finally someone who still builds the real stuff
@acestudioscouk-Ace-G0ACE3 жыл бұрын
The way you have the circuit diagrams printed out and on display is a great help. Another good video, thanks.
@MIKROWAVE13 жыл бұрын
Schematic diagrams deserve to be drawn pretty and legible. There are so many nice illustration tools out there now, many free.
@neiltan1939 Жыл бұрын
What a cool transmitter. Thanks again for another FB video, Mike. 73
@m0dad5 жыл бұрын
A great nostalgic project for over the holidays. Well documented and very interesting video. I built a one valve EL84/PL84 transmitter some years ago and it had a lot of chirp. I think this has inspired me to get it back on the bench again and start experimenting. Well done Mike with another great video. :)
@Isochest5 жыл бұрын
I remember this in an American ham radio book I borrowed from the library. A novice transmitter for 40 and 80 meters. HT was about 280 volts. It was my first transmitter and worked well. Next one was a 2 valve 6BW6 oscillator/multiplier 807 PA for 10/15/20 and 40m. That got better results as I had more power. The HT was 560 volts on the second rig.
@TheDavidnewkirk5 жыл бұрын
Wonderful. Some comments based on my recent findings: For a near-miraculous yoop/chirp reduction -- at 40, with FT-243 and larger rocks; HC-6s are just too thin -- put a 25-k pot (wired as a rheostat) across the 47 k grid resistor and, with key down, adjust its value down from 25 k. In the region immediately above the point at which there's too-little R across the crystal to sustain oscillation, you will find a slight output-power peak -- _and_ you will find that the rig generally puts out more power than with the original 47 k grid R. _This is without any regulation on the screen._ Proper tuning of a crystal-oscillator rig is not about tuning the output for a plate-current dip; that's for an amplifier, but a single-tube oscillator is not an amplifier but rather a highly dynamic environment in which the tube supplies its own driving signal. The correct way to tune a single-tube-crystal-oscillator rig is to adjust TUNE and LOAD for maximum output _in conjunction with best keying_; there's little value (aside from eye candy) in devoting a permanently-installed meter to the job. For the 5763/6417, keying will be best on the lower-frequency side of "output max," at a point at which oscillation still starts reliably on key down. (And when it's connected to an actual antenna system, the "correct" settings will shift; I recommend monitoring your transmitted signal so you can find that sweet spot again and/or as you change crystals or rain falls and shifts your antenna system's impedance.)Beam power tubes are prone to intrinsic-negative-resistance-based oscillations in the plate and/or screen, so, in the order of importance: Install a 47- or 100-ohm resistor between the tube's screen socket terminal and screen bypass cap; remove that parallel RL VHF-killer choke and install a 47-ohm resistor at the tube's plate socket terminal, between the plate and anything else; and maybe up the value of that 10-ohm grid R to 47 ohms.But if you do only one thing, try reducing the resistance of the grid R as I've described and tuning the output for max output/best keying. Suddenly I can use my first-ever Novice transmitter construction circuit on 40 m without wincing! 73, Dave/amateur radio W9BRD
@MIKROWAVE15 жыл бұрын
Wow fantastic research and practical info!
@Isochest3 жыл бұрын
My first ham transmitter was a Novice rig for 80 and 40 using a single 5763 from a book from the local library. Nice and easy to build.
@MIKROWAVE13 жыл бұрын
5763 is a great tube; one of the best for power oscillators.
@herbk84892 күн бұрын
Bravo = Well done video
@cwebs10005 жыл бұрын
Great stuff! I would rather build then buy any day. At one time I had rooms full of spare parts but gave it away so I had to start all over again. Thanks, keep the great vids coming. Carl AB1ZI
@984francis4 жыл бұрын
You're an excellent presenter.
@myvair5 жыл бұрын
Another excellent video Mike! I always learn a thing or two by watching them. de Scott W6EEP
@glenngoodale17095 жыл бұрын
This was an excellent and informative video. Very cool gear!
@KB4QAA5 жыл бұрын
Super project! Thanks for the tips on solving chirps. 73, bill
@ka3bhy5 жыл бұрын
That's a cool little project. Thanks!
@XE1YZY5 жыл бұрын
Great project!, congratulations and thanks for share!
@warplanner88524 жыл бұрын
GUD SIG OM - UR RST 599C 599C ..brings back memories, Mike. TNX ES BCNU DE K6WHP dit dit
@PapasDino5 жыл бұрын
Great little project Mike...HNY! 73 - Dino KL0S
@kengilcrest86705 жыл бұрын
Good stuff. Enjoyed it.
@-Todays-Tom-Sawyer-5 жыл бұрын
Awesome Mike...if I had 1/10 of 1% of your knowledge.
@wadepatton24335 жыл бұрын
Old skool "open source" the electronics and rf division. Lost me there a few times, but I'm picking up on it. 73
@Dazzwidd6 ай бұрын
Single active device transmitters are an interesting subject. I took my microwave oven, arranged waveguides and feeds for the antennas as well as keying for the magnetron with interesting results.
@MIKROWAVE16 ай бұрын
Shocking!
@Dazzwidd6 ай бұрын
@@MIKROWAVE1 Of course I'm being silly, I wouldn't want to frazzle the recipients. Imagine how dangerous it might get if there's STRONG propagation enhancement! 🤣
@DisabilityFraudKJW5 жыл бұрын
Great video. Thank you.
@davidmccarter9822 жыл бұрын
Actually the 1mH choke has a very important function. When power is applied to the plate circuit the 0.001uF output coupling capacitor will charge up, and the current flow is through the 1mH choke from ground. When power is removed the same capacitor needs to discharge, again through the 1mH choke. If the choke were not there then some DC would appear on the antenna, unless that antenna used a grounding Balun. So without that choke, a shock hazard exists at the antenna or RF output jack. Another trick is to use a 4.7k ohm 1W resistor in place of the RFC. Takes a bit longer to charge and discharge the RF Coupling cap, but it sure is cheaper.
@jeromegrzelak82362 жыл бұрын
Same chocks cost so much kg6mn
@coltronex5 жыл бұрын
Superb!
@randymiller77885 жыл бұрын
nice looking project, I made a similar one a few years ago for 40M but it was a one transistor oscillator and an RF match to the antenna, what I did not have was a harmonic filter, and i got a harmonic signal on 14M, which could not get rid of....de aa5oz
@jeromegrzelak82362 жыл бұрын
ouch mn
@Steve-GM0HUU2 жыл бұрын
😄 - did I detect some excitement in your manner when the little TX worked first time? Nice project and thanks for sharing.
@FunLab7375 ай бұрын
fantastic. thanks
5 жыл бұрын
Michael, Happy New Year has that home. José Luís - ea5bii-
@MIKROWAVE14 жыл бұрын
Feliz año nuevo José Luís !
@vreism4 жыл бұрын
Useful video thanks ta4ifg
@mohinderkaur66715 жыл бұрын
If we call the chirp a tweet, it maybe quite acceptable... great project
@geofham83325 жыл бұрын
Hi enjoy the videos, thanks. Any chance of a home brew power supply for tube transmitters as per yours? Thanks again .
@clydebennish21065 жыл бұрын
You must have a junk box the size of the library of congress. I think I have enough parts in my junk box to build an led flasher. This is the problem with the Ham industry - many times parts are hard to come by. Ive been frustrated by lack of parts too many times to mention. I dont know how many incomplete projects have sailed out my window due to lack of parts. Its too bad there arent more kit producers interested in vintage equipment at reasonable prices. Elmers dont give radios away any more as you mentioned was so in the past in another video. However, my friend's grandfather was very happy to take my last 1973 25 dollars for an S-38 that bit me if I didnt wear dry shoes. Another pseudo Elmer was very happy to have me repair half the shingles on his roof for an old model 28 teletype machine. The ham store was very happy to sell me an HW-8 kit with a swift kick in the pants out the door.. Some ham at a flee market was very happy to have me hall away a Yaesu 101 for top dollar, then I had to send the goofy thing to the factory for a 300 dollar over hall.. A kid cant even build a crystal radio anymore because he cant find a 365pf variable cap. What's the secret to ham radio?? Perhaps one must be a greedy sob - I sure met my fair share. Of course this post is not a reflection on you... just my experiences. You want to know what virtual reality is?? I received virtually no radio hobby support from my parents or relatives or teachers.. I earned my extra the hard way - virtually alone - as most of the hams growing up today are apt to experience. Ham radio operators are a dime a dozen; real ham technicians are hard to find - and its no wonder - its just too darn difficult to find parts. On the other hand if you want to buy an $800 radio filled with SMTs so small you need a magnifier you will have no problem.
@MIKROWAVE15 жыл бұрын
Junk Box Envy - the road to perdition.
@clydebennish21065 жыл бұрын
@@MIKROWAVE1 Dont you mean THE ROAD TO HELL IS PAVED WITH JUNK BOX HOARDERS... lol One crime is Idolatry, my crime is simple passion.
@MIKROWAVE15 жыл бұрын
I sometimes am accused of heresy mixing electronic and religious terms.
@clydebennish21065 жыл бұрын
Well, that's no worse than when Im accused of mixing metaphors or dangling a modifier... 73s... love your vids
@jeromewysocki88093 жыл бұрын
clyde bennish , if you can, try attending hamfests that have "flea markets" of electronic parts. I know that is hard to do because of the Covet-19 situation we currently are experiencing. Unfortunately, a lot of these old parts get thrown out when an old guy like me eventually becomes an "SK." I did my part to help a younger generation, by giving a whole bunch of tubes to a younger Ham who actively builds vintage radio stuff. Keep looking. You'll be amazed at what unexpectedly becomes available.
@imscuba5 жыл бұрын
Dear Mikrowave1, I have bveenb searching the internet and youtube HIGH n LO for a 6m CW QRP kit, NOT some MFJ thing either. I cant find anything and if I do its poorly documented. Any ideas?
@TheDavidnewkirk2 жыл бұрын
The RF choke on the output is not there only in case the plate-to-network capacitor fails. It's there to act as a pull-down across the loading capacitor -- in effect, to allow the plate-to-network capacitor to charge AND to keep the RF output line to the antenna jack at dc ground -- when a low-resistance load is not connected to the ANTENNA jack. (Without such a pull-down, the plate supply would charge the plate-to-network output C in series with the loading C, with most of the voltage appearing acoss the loading C.) I've seen a 1/2 watt, 10 k to 22 k resistor to provide this pull-down function instead of an RF choke; a resistor may provide more safety than an RF choke if the plate C fails, as the resulting current pulse might well cause an RFC to fail open, losing its protection, whereas plate-supply current through a small 10 k to 22 k resistor will cause the resistor to smoke, alerting the operator that something's wrong.
@MIKROWAVE12 жыл бұрын
The choke makes for a great story. So does the smoke. But I already got electrocuted on the key, so...
@brucegordon72484 жыл бұрын
I wonder if this was a transmitter that WN1LRK a novice was trying to build from scratch, or was it a commercially made transmitter or kit. It looks like it was commercially made because the lettering looks very professional. Looks like the old FT-243 cleaned up the chirp for the most part.
@VintageTechFan Жыл бұрын
Looks like Letraset. If you are careful, it looks very professional. Needs some clear coat to be durable though.
@geckoproductions41284 жыл бұрын
Would love to experiment with building some of these, but no HV PS. How about a video on a nice general purpose P/S?
@MIKROWAVE14 жыл бұрын
It is simply Shocking! You need a power supply. OK OK lets see what we can do in 2020.
@guillermosempron57765 жыл бұрын
Because is CW.
@laythabdulwahab94983 жыл бұрын
It is really an excellent project,thank you very much.But my problem is in the calculation of output pi network so could you please give me precisely how to calculate it even to any tube or transistor.thank you.
@MIKROWAVE13 жыл бұрын
Well a good approximation starts with calculating the impedance that the tube (or transistor) is presenting at its operating point during full power. So if we have a 250V supply and the meter reads 50 mA, the estimate is 5000 Ohms. This is 12.5 W input power by the way. So you are trying to transform 5K to 50 Ohms. Then pick the Q you want. Say 5 which is reasonable. Then just work the PI formulas at your frequency.
@clifffiftytwo5 жыл бұрын
How about a "Add a 6146 PA to the 5763 transmitter" video? What would the novice do to increase his power?
@MIKROWAVE15 жыл бұрын
Charles Caringella, W6NJV, Easy-to-Build Ham Radio Projects (New Augusta, Indiana: Editors and Engineers, June 1967 CE), was the basis of this project, and he includes in another chapter, a 2E26 Amplifier stage which is the little brother of the 6146. This got you up to the 20 Watt level. But the Radio Amateur Handbooks of the 50's and 60's were full of 2 tube novice rigs, some using the cheap 1625 tubes that were available surplus and even TV sweep tubes. These could get you to the Novice legal limit.
@jimw7ry3 жыл бұрын
If you convert the meter into a volt-meter, you can use common values to make the meter read correctly. Use a 4.7 (or any other low value resistor) shunt, then a resistor in series with the meter, or even a small pot so it can be calibrated easily. Which you describe at 14:10 Good example here: www.electronics-tutorials.com/test-equip/meter-shunt.htm 73 Jim W7RY
@MIKROWAVE13 жыл бұрын
Working with analog meters and re-doing dial scales for restorations is a lot of fun. Thanks Jim.
@user-dh1kq3eh8q5 жыл бұрын
Сретна нова 2019 година,браво.73 милан
@MIKROWAVE15 жыл бұрын
Спасибо 73 Милану и счастливого нового года постройки радио
@MauriatOttolink3 жыл бұрын
The fuse is to blow, should the anode .001uf fail thus putting B+DC into the Pi tank Network. The output RFC would ground and damage the B+ supply without a fuse. So if you do use the hole for something else, put a wire ended fuse holder or similar inside or in the power supply lead.
@MIKROWAVE13 жыл бұрын
Fuses are cheaper than chokes too!
@robinsonsoto84713 жыл бұрын
This is Colpitts Osc.
@MIKROWAVE13 жыл бұрын
Yes an Electron Coupled Colpitts Crystal Oscillator.