AM Transmitter Kit for Vintage Radio
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- čas přidán 27. 05. 2020
- AM Transmitter Kit for Vintage Radio
Do you need an AM transmitter for your vintage radio? Designed to work from 500Khz up to 1600Khz, this AM transmitter kit has a 3.5mm stereo input jack so you can connect it to your phone or music player and transmit your own sounds to any AM radio receiver be it a vintage radio from the 30's or a modern plastic set. This AM transmitter kit provides a comprehensive way to build your own AM transmitter with a little time and patience. With the current state of the AM broadcasting band in the UK and transmitters being turned off at an alarming rate you will eventually need a device like this to keep that much loved vintage radio useable. This is a cheap AM transmitter kit from AliExpress that enables you to transmit across the AM broadcast radio spectrum and beyond. For just over ten British Pounds you get this AM transmitter kit delivered from those electronics suppliers in China.
If you want to buy this kit, then link --- www.aliexpress.com/item/40000...
If you have not signed up to AliExpress before Enter this code in your account settings and get $19 credit and help me out too! Code as follows... INR54S1E - Věda a technologie
Hi George about the same results i got with mine i cant decide if the distortion is from the input amp or the output stage the modualtion control has little effect. With a 9" aerial the range is over 15 foot .a circuit would be helpfull. great video
I think the distortion is from the TDA chip providing far too much gain. The controls have little effect as you have found. I will try it with a filter at some stage and a longer aerial and see how it behaves then. Circuit diagram I found in a review comment on another ali sellers listing, ae01.alicdn.com/kf/Ud94d569f2d8a4a62bdd1be79634bc60b3.jpg
See my comment above. Or maybe below. : ) Not at all a bad little rig.
Bit of an update. Done some insomnia experimenting & anything far removed from a 50 Ohm load results in a distorted waveform : ( A few feet of wire alone won't cut it without an ATU. Ergo, don't know how much you know Rob, but best bet is a couple of 100 Ohm > 1/2 Watt resistors (NOT wirewound) in parallel solderered between aerial outlet and the junction of the adjacent 2 470pF caps. Makeshift aerial can then be connected to the aerial connector as usual. Keep the voltage down to 5Volts and it will still deliver the advertised 500mW. Rather inefficient solution, but sound quality is most satisfactory for yardcasting.
A tip: watch movies at Flixzone. I've been using them for watching lots of of movies these days.
@Ralph Paxton Yea, have been watching on flixzone} for since december myself =)
I built it this weekend. Easy project. All parts provided. Nothing left out (except knobs/dials for variable cap and audio input potentiometer). With a little twiddling I finally got a strong, clear signal with minimal distortion. I went rouge and connected it up to my outdoor SW antenna and ground. I dove my truck around and listened to the transmission with my truck radio. The signal covered most of my neighborhood block. I'm sure I could improve transmission range with a better tuned antenna. Presumably there are lots of spurious signals being generated. The transmission signal drops off pretty quickly outside of my immediate neighborhood area. It will make a nice local pirate station.
I made a kit like this but myself ;) it works similar to this but the satisfaction is greater than just buying the whole kit :D
Just finished my kit, it has a few more capacitors and coils then yours but I guess, like everything should, it improves with age. For an antenna I dug through my cable drawer and found an 8 foot coil of inside house wire for old telephones. I stripped off the outer cable and took one conductor out (green ) and wrapped it tightly over a long antenna from an ancient AM/FM luggable radio that I junked. Then with a long coil I covered it with a heavy duty shrink wrap and heated it. I came up with a rather solid antenna and soldered it on the mount that came on the board. When I fired up the transmitter and fed it some output from our local AM radio station it came across another receiver across the room nice and easily as clear as the original set hooked to the transmitter. Wish I had a good case for it, been playing with either building it in my wood shop, or perhaps cutting some old CD Cases up for a clear case to hold everything in order. I didn't build a base for my antenna so I have to have the unit on my chair so I can lean the antenna against the back. Works for now I guess.
Hi George, that output is something else. Good bit of kit building :)
Indeed it is!, still a filthy little boy!
George you are getting better and better!!!! Cheers my friend :-)
Many thanks!
Nice little kit George mate.
Saw a ready built version recently. At least it had a token gesture 3 element LPF on the output to help keep the sprogs down.
The less components the better the results. My first AM transmitter was a one germanium OC44 transistor circuit, modulated by the output of my portable reel to reel tape recorder ie a basic 4 transistor 1watt or less amplifier such as in portable radios etc. With a 5m antenna it had a range of about 1km on a 6v supply. Without the anntena it's range was about 10m. The sound fidelity was excellent and stable without any drift. The oscillator and feedback coil was wound on a 15cm ferrite rod.
And you be safe too my friend, good to see you again.
Many thanks for stopping by!
I thought it was Derek braning for about 5 minutes. Great channel, good video and a new sub from me.
I bought the same kit. ( before I watched your video thought) and In hef the simular problems.
I miss a few important items, and a have some rubish left.
Doesn't work...
To bad though, because I like having a low power AM transmitter because of my old tube radio's get to work.
Not much AM stations in Holland..
Wel keep up the good work.
Enjoying your video's
Best video 👍🏻. This stile kits is much butter ready to operative. It a not easy calibrated.
Nice video George. Be interesting to see if you can clean up the output but hey ho there’s always the fire route ✊🏻
see, you are infected too.... hey ho man strikes again...
Hi George. Thanks again for the video. Yes looks like the tx was rather dirty. The sound was not the best but that’s am for you. Yes the Chinese seem to give extra parts with their kits. All good fun. And picking on Shaun again? That’s the way. Thanks Derrick.
It was good that the original listing also shows how dirty it is, as a badge of honour! I think it needs some levels playing with, the distortion could possibly be from front end overload as well, the grundig is particularly sensitive on MW. Picking on Shaun.... He has at least two of us saying Hey Ho now. It is catching....
Knocked it outta the park George,
Many Thanks Keith. I have knocked it somewhere, I can't find where I put it after putting the next thing on the bench!
I'm so glad I found your channel, they are the right combination of education and entertainment or "edutainment" as the trendy buzzword is! It wouldn't be too difficult to clean up the harmonics with a filter...or would it.? 73s.
Easy enough but I just built the kit. I didn't want to modify it as such because some might not understand the additional components change.
Thanks for putting one together so we can see what its like, not fantastic I guess. My valve TX I use sometimes, is Suppressor Grid modulation and has negative feedback and I must admit I get good results with that. Thanks, George.
The design leaves a lot to be desired for sure. It isn't inherently bad, just lacking in filtering and poorly implemented.
How would you add filtering to this to get rid of the harmonics being transmitted?@@GeorgeChristofi
@@kwacz Probablt with an lc network on the output to the antenna or even some form of impedance matching of the antenna wire.
Real neato George! ~Jack, VEG
Many Thanks Jack. Missed seeing you around, hope everything is ok your end.
I bought that thing and put it together. three parts were missing. you understand he's not working now. I could still replace the two missing capacitors, but the trimmer which is situated nearby the antenna output is still missing.
Unfortunately.
luckily it doesn't cost that much.
You could try adding some filtering to the crystal to turn it to a sine wave to help get rid of those harmonics.
It did sound quite distorted. But I have to say I haven’t managed any better with my own AM transmitter builds. Be interesting to see the modulation do you have a modulation meter. Probably some form of limiter would help . Thanks George alway entertaining regards Chris
I could run it into the 2955 but it's probably not worth the full scale effort. Saying that, having it permanently on and Bluetooth connected might be a good test setup on the bench.
Hey George. Your videos are looking good. I hope you are well. Nice background.
@@GeorgeChristofi Things are pretty much the same for me - glad to be involved with CZcams since it's always been "work at home". :) The rest of the world OTOH! But I'm grateful to be doing well. Hope you got back from your trip okay.
@@GeorgeChristofi o
Hi George, have not seen you around lately.
With all those harmonics I would be afraid to use it, the FCC would be at my door...LOL
I've been around but not doing much CZcams. It is a nasty little design that the original listing seemed proud to show the harmonics all up the band! Hope you are keeping well and the family is ok . Take care, all the best, George
Hello, i orderd same DIY kit about 3 monts ago and one of the components was missing ,it was coil B1. Problem is that i dont cnow parameters of this coil and seller promised he will send me missing part and still nothing. Please could you tell me parameters of this coil, it will help me lot.
George - thanks for sharing. The harmonic output looked bad on the spectrum analyzer. How far down were the harmonics? Best, Don
A lot!.. they went all the way to almost dc as well as all across the ham bands.
The new kits are now bilingual with proper item description.
Thats useful to know. Many thanks for the information.
I am looking for a medium wave transmitter just to transmit across the room in my house to some vintage am radios i restored. I bought several transmitters and they all are loaded with the harmonica you show and transmit all over the place. They hum like mad and barely make it to the radio setting next to it.
Do you have any recommendations or even schematic of something with decent sound quality and reasonably clean output?
Many cheap and simple designs are available. Try the one from my transmitter on a sheet of toilet paper video or the breadboard transmitter video.
What a fun video! I have to say even if the instructions were in English, they still would be unintelligible for me lol😁👍
It's a fun item but not really that good Martha... The instructions are vague even when I did translate them afterwards!
Hey George!
What are the levels of the carrier and the harmonics?
I agree with you...it is basically crap. If you were going to design and build one of your own design, what would you design? Care to go for it and give us a schematic?
The carrier level on my spectrum analyser showed the fundamental carrier at -10Db, with the harmonics only -30Db lower. Biggest issue was the width of the signal. If you put it near a radio with a poor front end you would hear it all over the MW band. I wouldn't do the design from scratch thing because it would be re-inventing the wheel. A lot of good designs out there already. This one needs the audio gain and the output looking at to clean it up, not much more I'm guessing.
George the Tesla model is the 532A. With wot seems a duff mains transformer. Cheers.
Ok Jeff, been looking at the transformer on the schematic and in reality pretty much any transformer capable of running a 6 valve set should do. I haven't put the schematic or service info through translate yet but from the figures it isn't really anything that can't be replaced. Do you have a copy of the drawings?
@@GeorgeChristofi Thanks George. I do have drawings. Think I got them from Radio Museum. I will see about emailing them to you. Thanks again.
Interesting that you mentioned AM broadcasting stations shutting down. I think it is a grave mistake. I am already missing a few SW channels on my shortwave due to Am stations being shut down.
We have lost around half a dozen AM BBC local transmitters this year alone. BBC Radio 4 on 198Khz is on its last transmitter valve and there are none left in the world to replace it with. Once that fails, we will have no Long Wave transmitters in the UK.
@@GeorgeChristofi I honestly think it is a global initiative to restrict long distance communications. that way communication can be globally controlled to regional clusters. They are working hard to control the narrative.
Muito bom gostei muito bom dia pra você
Would be interesting to see how far you could go to clean up the distortion :-)
It's a thought, I'd like to try sometime but when is the thing...
nice video.... George you try to change the PFilter?
not on that unit. I was tempted to add a separate pi filter onto the output but the whole design is really not worth pursuing.
Sorry for a second thought was the spectrum display from a bit of Yaesu gear. I think you should build a 1K amp and spin up some of your old 78's for old times sake.
max range reached? distance?
nicely done its a bit overly complicated for such a messy output Ive seen simpler designs work just as well !
Indeed Benji, I have built simpler cleaner units on toilet paper! If it had adequate filtering I think it could be quite a good kit with a significant range.
@@GeorgeChristofi I expect it could be.it would nice to have a valve one
I think the transmitter would have a lot more range if it didn't have all that wasted energy in the harmonics. I've heard that these Chinese electronics kits are actually designed by engineering students as part of their university education. The best ones are then chosen and sent to be mass produced by the factories in kit form. As you say George, it is what it is. Hey Ho.
See, you have caught the Mancave virus. Apparently it takes a lot of therapy to cure it. The transmitter on the other hand just needs filtering, the input stage looking at as well as the output control, a metal box and a good aerial.
Can someone help me. I puy together one of these kits but not sure if it's working. Do I need to connect an antenna to it? I only have what came in the kit and none of videos seem to elaborate much on what else is needed if anything.
With this kit you cal fit an antenna but it will work if you put it near a radio. The antenna will increase the range.
Hi George. Gone adrift with the Tesla. Changing perished cables from mains transformer . but got one wire adrift. They both go to the volts changer plug, got one on. Dont know where the other goes to ?. There are 5 connections. Can you tell a dummie how to test for which one. Cheers
Depends on the type of voltage changer it is. If it is the same as Philips ones with the pins then I can look it up. The rotary switch type the same. Let me have the model of your Tesla and I'll look at a schematic.
Thanks for reply George. I will put some best wordage together to give you a better idea and a pic
I am at the mo going through it like a dose of salts as they say.
Still got to do all the caps. But magnifying glass and finger is finding bad joints (is there a bad joint)lol
But ohm meter on primary "says no"
It will not stop me from trying . buying a new bit. Making it look and hopefully sounding good.
Thanks again George
Nice video George. So, all in all is it a case of good idea, poor quality kit? Your videos are looking exceptionally professional, not that they weren't before but they have def gone up a notch.
Think that is sort of a reversal, the kit is quite good quality but without the basic output filters its a bit of a sprog box, the banger in the dog poo approach to generating RF.
Crickey George, I'm of an age if you built a transmitter , the radio interference dept. would track you down, thankfully a kindly a radio engineer from the R.I.D, steered me away from the dark side to amateur radio. I wonder what the range would be with a good aerial.
You and me both Paul! In fact, I was given a box of confiscated fm transmitters by one RIS officer many years ago and i bought my HF linear amplifier of a different retired RIS officer.....
@@GeorgeChristofi Of course RIS they were called Radio interference Department around here, duck blue vans with Black writing, anyway ,I think the Radio Cruncher should take your advice with some of those radio's baptism of Fire would put an end to many of the problems, in the workshop I worked in someone came in with a sob story, about how a radio was their relatives they didn't have a lot of money could we fix it, as it mean's so much to them, only to find when it was fixed they advertised it and sold it, that toughens you up to the public,
New friends🎉🎉
George, do you know the value of capacitor "203", would you measure in circuit? Any help would be appreciated.
the value 203 is 2000pF or 2nF. The only way to properly measure capacitors is out of circuit.
@@GeorgeChristofi 20nF - 20x10^3
@@radosawrogozinski8560 I missed a zero. Brain not working.
@@GeorgeChristofi It was 0 so really nothing. :) I assembled such transmitter 2 weeks ago. It works without distortion when input signal isn't too strong. They put 200ohm potentiometer instead of 50k (!), there were no 20nF capacitors in the set, only 10nF, 100nF caps have 60nF in fact, so I used my own parts. Carrier signal is weak - one high sine wave, two lower ones, etc.
...are you tempted to modify it, George, to improve it's performance ??
Tempted yes.... Bothered... Hmmm... I might if I want to squeeze every last ounce of performance out of it but I shall do some testing.
Hey , how much is the range?
I have not done a full range check because I have not fitted a full antenna to it.
I think that kit needs ' The mallet of stubborness.' :-)
If that kit was porcelain, i would call it Crap-o-Demontey :-D
It needs a low pass filter and a dust bin ha ha.
It needs a low pass filter for sure... a good aerial and a metal case. And burning....
Pity it splatters all over the band, easy fix though?
Yes Dom, a simple pi filter should do it in either low pass or band pass config. If I can be bothered!
Thanks for that George. Shame its crap sound quality. I think a good one would sell like hot pies. Bluetooth seems to be the better option. Hey-Ho.
I may well look into the design and see what improvements I can make.
it does what it is supposed to do but not much more!
I don't really like the modulation,.
I also liked to build it but my self-build transmitters are better.
for the self-builders among us this link:
members.home.nl/radiomorningstar/index1.htm
Greetings from the Netherlands!
Rob
FM transmitters sound and work much better.
true, but most vintage sets are AM
@@GeorgeChristofi, yep. Sorry I missed the significance of the channel name when I watched the video. Fortunately for me I got one of those little Lafayette (I think it is,) tube AM transmitters that was in the bottom of a junk box I bought at a ham swap for $5. It worked, and I was delighted. It sounds pretty good into the AM broadcast bands on my old tube Hammarlund shortwaves. I have an Arborphone Model 27 TRF radio that I'm eager to get tubes for, (though they aren't cheap.) I'd like to run vintage radio shows into it from the AM transmitter.
@@johnwest7993 Not a problem. I do have a couple of FM units too and I did import one of those realtor home transmitters from the US as a comparison from commercial to homebuilt units. The one I do want to build is the one that @AllAmericanFive has on his channel many years ago. That is a tube unit and it sounds absolutely perfect. Another of my get round to projects of which I have many! I do have a homebuilt radio that was constructed in 1925 complete with tubes and power supply but have yet to run that up. One more project.. its never ending here with so much in my storage yet to do.
64 - 108 MHz (HRD-831)
As it stands this is pretty dreadful device and probably not legal. if you put a scope on the carrier it will not be sinusoidal ans as you know this will be causing the interfering harmonics. I would try and reduce the output and also try it on 12v as well as with a filter on the output at the frequency you will be using it at. Also for AM limit the audio bandwidth to 9 Khz. Also I recommend a metal box and earth that, Then you should be OK.
Any am transmitter is illegal over here anyway but the point is moot... Its a bag of nails masquerading as a pro product.
Can't complain for £11
It's a piece of garbage - a waste of time!
You are not wrong for sure. I have seen much better transmitters than this one
This is the worst kit period ever period!