High Quality AM Transmitter

Thanks, I've always wondered how the AM circuit looks like, we only had lab works where we had to simulate it in Matlab this semester in uni.

Great circuit, Jason9. Your work is always badass

Interesting circuit :-)

Thanks!

There's that fuck again spamming shit all over. Anyway good circuit. AM is easy, you can probably whip one up, with even 1 transistor.

One transistor? One diode! Look at my latest circuit.

@thebugger, now the offending text is gone please now remove your comment. Thanks.

Or please remove swear word.

Do we elected a sheriff?

Id moderate B-)

I got Igor to remove most of idiot penis last night - unfortunately he missed 3 of them which I’ve pointed out again. Hopefully they’ll be sorted tonight.

I do wish everyone would stop swearing. Even though I understand their frustration it just makes the site look worse still.

RK it's great you can contact Igor! Please tell him the only way he's gonna put an end to this torrent of abuse is by ending free trial periods, or atleast deny the free users to create posts here in the community!!

Then he could request to us all legitimate users to go back through our own posts and delete the bad language we used to counter the troll

I'm with you on cleaning up EC, i think there are many very young users here and i want to introduce this app to some of my young relatives. EC can be a safe fun place where it encourages them to learn electronics, not a hostile place like it is now

This typically not much use to anybody therefore should remain private. Thanks

Mr. RK is the same kind of troll. I remember his words HE has choosen against me and @thebugger. As you can see now, deleting this comments by Mr. RK does not make him better then big_penis_joe. RK is here for years and just helping people tuning a current limiting resistor for a 20mA LED. He presented 5or6 circuits taken from internet maybe. Now he gets active as our sheriff? No thank you!

@Hurz you took a dislike to me from the very start for no reason. You have a wild imagination or, perhaps, it is a deliberate lie in that I have NEVER said anything negative about @thebugger. I hope he reads this and confirms that point. I rather like him and what he brings to EC. Conversely, you often choose to unnecessarily put people down, even when they are learning unless, for some reason, you are in a good mood, in which case you condescend to help them. You are too keen to try to show how much you know by pointing out how little you think others know. Look at what you’ve written above! People praise your electronics knowledge, rightly so, but it’s your personality many people can’t live with. May I suggest you pipe down or I will inform everyone why you really withdrew your 600+ circuits. In the meantime I will leave everyone to judge me themselves by my actions rather that what some random like you says. I make no apologies for trying my best to clean up EC. Call me a sheriff or whatever you choose - only words!

Havn't you said to me Im a fool, and thebugger came into the discussion and said you RK are a fool. The rest of this discussion I better do not repeat for you.

Wow, normaly your activity in EC is limited in dialing resistor values for LED current limiters to 20mA. This is what you did the last two or three years. Nothing else, accept being a troll and commenting wien bridge oscillators which do not understand till today, right. Last think I saw is work in progress ....

And the first dislike you got from me cuz you called another user a "noob" because he came with a LED 700mA, while in your limited mind there are only 20mA LED worldwide available. You got this "dislike" for calling a user a NOOB. Just to remind you.

And I put down my 600+ circuits, because there are trolls like YOU in everycircuit!

Facts are important. You seem lacking! If you bothered to look you'd see I've been a member for a year! I'm pleased you read my posts - gives me a cosy kinda feeling. I have many private circuits - like zorgrian and others I choose to keep them that way. Consider this, who is it gets LED currents wrong - NEW USERS. Who is likely to need help, perhaps more than others, - NEW USERS. Presumably you are above helping with such 'trivial' circuits. I choose to help them because they may become the experts of the future on EC or, at least, get much enjoyment from it. So, stop whinging and do something useful.

Come on people - for me or against me - your comments are very welcome!

...and Jason, sorry, I didn't mean to hijack your thread.

No problem. Also, I’m for you. I just don’t quite get how @hurz came to dislike people like you and @LeButch so much. It doesn’t quite make sense.

Wow, RK all your public circuits are boring, to be honest. And if this is your best of collection, I m happy you keep most of your circuits private. And why are you so active since big_penis_joe is online? Are you so bored to wait for such an idiot? Fact is in the last years you were never really helpful for other users. Long time you just pissing around. You are a very strange member of this community. Go sleep again.

What exactly is the cause of your jealousy?

What threat do I pose?

Amused

I'm getting the popcorn ready...

Ahh, you’ve taken my advice and gone away.

You should all know that this problem child problem isn't going away soon, e's staying put as long as he's got his free cake EC, which he is gorging on. Being nasty is just the cherry bonus on top for him, so passively ignore him or actively swear at him ain't gonna make aaany sweet bit of difference at all. The ONLY thing will stop him is taking away that cake! So someone pleeease tell Igor to shut that drafty back door (end the free trial or atleast make the forum read only to the freebies!)

Working on it.

I'm using a free version and I'm one of the top contributors to this app (along with some fellow engineers). I'm against cutting my access off, just because some spoiled brat decided to spam all over.

How's that? Isn't it only 24h free trial, then then re-register again for another 24h? How are you retaining your user profile??

... that don't make sense at all thebugger. You must have paid for this awhile back, or you using a cracked version?

No! No that doesn't make sense at all. Unless thebugger has some kind of legacy deal or insider trading going on, it is impossible. The buggering lecturer who learns while he dictates is a high contributor in all senses. At least VHF is no longer FM, or is that still true? (In his mind only)

http://everycircuit.com/circuit/4944803988242432

I've modified this circuit to work on the 40 meter band. 73!!!

Actually, i am surprised that you guys are not into ham radio. Its good fun and with all your knowledge, passing the test should be trivial... 73

I am into ham radio, and all things transmittery for that matter. As a matter of fact I'm currently working on a 5W VHF amplifier in the 87-108MHz range. Ham radio is a little harder for me, because I live in a city and have no place to extend an antenna of these proportions. I do have a few tube transmitter circuits developed, but have no means to test them as previously mentioned

Hey thebugger you still ain't explained how's your free access working?? I seriously doubt you been using the trial periods all this time, so the changes would not affect you!

@zorgrian, nice! I don’t really know anything about radio other than AM is amplitude modulation and goes from 500kHz to 1.5MHz and that FM is frequency modulation and that it includes a spot at 100MHz. I don’t really know about what’s in between/above/below, so I don’t know anything about the 40m (7MHz) band and I didn’t know that it was AM. Also, prior to this comment there were 73 comments, and what’s up with you and the number 73?

@thebugger, you could use a magnetic loop antenna. This is stealth operation and highly suitable for your situation. These antennas are highly efficient, dont need a antenna match circuit and are low cost to build

@Jason9 - all the more reason to investigate. AM is amplitude modulation, however it has nothing to do with the frequency used. Even Morse code is a simple form of amplitude modulation, just one where the amplitude is high or low or even on or off. SSB is another form of amplitude modulation. Then there are FSK modes including speech modes.

The 40 Meter band carries all manner of modulation modes

Thebugger, you could test your tube PA output transmitters into a dummy load. I see that youre interested in broadcast band 'community' radio. OK its probably illegal but you can get away with this, especially if you keep the power down to about half a watt to one Watt. Half a watt goes a long way with a good antenna. A dipole can be made for this frequency band using two telescopic antennas with a 1 cm gap. To tune it you need to get or build a power swr meter. You will find that when in tune the Z of the dipole is 75 ohms. However, this is easily changed by moving one of the legs of the dipole up to about 30 degrees, with respect to the horizontal (leave the other side as it is). Like this you can get the antenna to respond at 50 ohms with swr at 1:1

The above is for broadcast band at VHF

There is great satisfaction possible from transmission. In an urban area at VHF, there are so many reflections from buildings that if you keep the power low, they can never find you! Actually, the most common way to get caught is by people you may have talked to denouncing you to authorities or by some nice neighbor seeing your antenna. The antenna can be disguised

I am not advocating that you break the law.

However, the law is not justice

Actually I was just thinking of building and tuning my transmitter in the city, and using it in my village. My village is in a agrarian region and I can easily scope 10km with 5W. I'm using a monopole antenna for the FM transmitter. For now, I think I'll keep it to VHF, when I get my license I'll start experimenting with MW. Anyway I don't have a SWR meter. I'm tuning my circuits with an RF probe I made. It can quite accurately show you the resonance frequency of your antenna.

And Jason, Z is right. AM, FM and PM stands for the modulation technique used to change one of the properties of one signal, according to the properties of another, irregardless of frequency. Every modulation technique in existence uses one of these three basic modulations to do its job. Even digital modulations like QAM, PSK, ASK or FSK are just one of the basic modulation techniques or a combination from them. Even an audio amplifier can be viewed as a modulator. It takes a 0Hz signal (DC) and modulates it into an AC signal with a frequency, amplitude and phase (in according to the properties of a controlling input signal). Take it from me, almost any nonlinear operation in electronics can be viewed as modulation.

What you're referring to, are just some Law regulated frequency ranges, that use a given type of modulation. These regulations are done with a reason. For instance the AM range you mentioned, can most definitely be used for FM. But imagine what that'd do to the spectrum. An AM channel is 8kHz wide, and can even be further reduced with SSB, so you can fit more than a hundred channels in that range. Using FM will broaden the channel to 200kHz leaving the space for only 5 channels to coexist in any given time. On the other hand the VHF range is quite wide. You can fit over a hundred 200kHz wide channels in the range 87MHz-108MHz without mutual interference, and furthermore this end of the spectrum is more noise free than the lower part AM uses. Why not take advantage of the superior quality FM gives you, and the noise free environment VHF gives you. I mean yeah, you can fit over 25 AM channels in a single FM channel, but what's the point. Also, as you're probably well aware AM is quite wasteful (purely electrically speaking), having an efficiency rates of that of a steam train. The bigger range that comes with the lower spectrum can compensate for the utter inefficiency of the transmitter. FM transmitters are actually quite efficient (sometimes up to 95%), so the extra power it needs to compensate for attenuation at VHF, is considered reasonable.

I believe you Robert_Kidd, I also support the abolishment of verbal vulgarity including attacking members of the community by making condescending remarks. What I find remarkable is that one member in particular, the member who’s been attacking the comments you made to the “newbies”, is a notorious cyber bully! He attacks anyone who offers advice to other community members if he believes they lack elementary electronics knowledge. And yet this “golden boy” gets away with this appalling behaviour owing to his alleged electronics knowledge. What we need is the ability to block troublemakers who believe that their experience entitles them to be condescending to others...

You cannot get a license to transmit medium wave. Unless you have lots of money to pay your government or unless you are the government!