Challenge Thread: The fastest breadboard oscillator on the mudball

[0culus]

...enough to get a stable reading on the 5350B microwave counter.

I'd say that is a valid entry!

I feel pretty good about it too, so I'm going to say that I've broken 1GHz now. 

[BreakingOhmsLaw]

oculus, give that whole circuit a good blast with cold spray and post results please. ;-)

EDIT: take care not to feed DC into the counter once the condensation kicks in.

[0culus]

oculus, give that whole circuit a good blast with cold spray and post results please. ;-)

EDIT: take care not to feed DC into the counter once the condensation kicks in.

Yeah, I've got dc blocks and am not connecting anything directly to the circuit. All it did was make the frequency vary wildly, and the current draw went negative on the milliammeter I'm monitoring with for a bit (!).  It has been slowly converging back on the state shown above as it warms back up.

What is the purpose of this?

[edit] There's an intermittent problem with the milliammeter...sigh...repair queue time...

[BreakingOhmsLaw]

What is the purpose of this?

You will find that cooling down the FET can give you a frequency boost of up to 25%.
Reducing the temperature will increase the mobility of the charge carriers in the channel of the FET because they get less flak from the other atoms they are passing through.
An analogy: it's easier to run through a crowd when everybody isn't moving. Cooling down the FET lowers thermal noise and atom movement.
The reason why your circuit starts to go fubar is probably the water messing with the parasitics. If you can, just cool the FET ( rig a little cone made from kapton for example).

Edit: before anyone gets triggered, yes, it's quantum mechanics, Boltzmann and Planck at work. Not going to open a can of quantum mechanics here though. :-o

[hendorog]

Oklay...  just happened here...?

I generally tend to agree with Oculus' surmise; ogden has been nit-pick trolling the thread pretty hard, and unless joe is outright lying, he has a history of thread-stalking joe.

Joe's response, while it may have been viscerally cathartic, was def a bit OTT for a public space; it should've been toned down or if the venting was necessary, taken to PM. 

But seriously... this is a pretty obvious case of personality-clash oscillation.

Ogden has an established track record as a troll in multiple threads. So no, this is not a personality clash.

He or she prefers the argument over the engineering. Shoulda been a lawyer I guess.

[mnementh]

Please don't quote part of my statement out of context and try to counter it as if the rest doesn't matter. I know EXACTLY what is happening here, I described it in precise detail, and in case you didn't realize, I was saying that BOTH parties needed a time-out, not just joe. If you're suggesting that only ogden needed that, then you're the one practicing law in the wrong bailiwick.

I generally tend to agree with Oculus' surmise; ogden has been nit-pick trolling the thread pretty hard, and unless joe is outright lying, he has a history of thread-stalking joe.

Joe's response, while it may have been viscerally cathartic, was def a bit OTT for a public space; it should've been toned down or if the venting was necessary, taken to PM. 

But seriously... this is a pretty obvious case of personality-clash oscillation. This is hardly new territory; we've been dealing with this kind of passive-aggressive back & forth since the days of UseNet and the solution is pretty well-established: BOTH parties are responsible. Not JUST the troll, and not just the one(s) feeding the troll. Either both/all or none should be given a time-out.  That is why we call it a time-out: Not a punishment, but forcing all parties to step back and consider their contribution to the NOISE part of the SNR.

All your post above serves is to stir that shit back up again when it has been resolved as well as it's going to be until the parties involved return to this space, and either start it all over again or kiss and make up. 

Please, for the sake of those who are here to learn something, let this rest for the duration of the time-out. You're just contributing to the above-mentioned NOISE part of the SNR. And so am I, so I'd really rather not be dragged into another such debate in this technically-oriented space.

Cheers,

mnem
Anybody got any peanuts...?

[mnementh]

In Joe's defense, he has been documenting with videos up until about a week ago...another video featuring the new circuit and demonstrating its construction in detail would be great IMO. But yeah, he has been a bit coy and I think one should definitely at a minimum provide high quality photos and tell us exactly what parts you're using, as I have tried to do with each "thing" I've attempted. There's no reason to hide anything about your circuit here unless you are, in fact, cheating the system outside of the spirit of gentlemanly competition. I say this because I support creative RF design as long as the breadboard is intimately involved. Otherwise I could build my circuits Manhattan style.

Yeah, that's where I was going with my comment; his photos and video show enough to titillate, but either not enough clarity or not the whole picture all at once. I get that he may be playing coy so as to not "spoon-feed" us the answers. I'm down with that to a point. But his documentation definitely skirts the realm of sleight-of-hand. 

It seems to me that the entire point of this thread is in a way to do precisely that: maybe not to spoon-feed it to us, but at least to get those who are strong with the μwave voodoo to help us break down this black magic region of electronics into small, digestible chunks so we mere mortals CAN grok in fullness. 

mnem
 

[0culus]

In any case, I'm putting this project aside till I get some faster parts and some magnet wire in hand. I am now shifting to troubleshooting the Tek 585A I just got...

[T3sl4co1l]

Dipping my toe in the 1GHz+ club.  No vacuum tubes here, just a good old fashioned 2N5179.

Transistor pins, left to right, are E, B, C (case is the 4th pin, N/C).

Ignore the squiggly wire on the top left, it's out of circuit (should've taken it out of frame..).  Power comes in from the left (blue, black), 8V.  H-field probe laid over the circuit goes to spec; solder roll used as weight to hold it there.  4.7k and clip leads are just for voltmeter.

Harder to see from this angle is the resonant stub, about 50mm of twisted pair coming straight up from the board.  It's very nearly end-on in this view.  Plugged into B-C positions.

A molded choke supplies collector voltage, and 10k pullup and 3.3k pulldown supplies base bias.  1k supplies emitter bias, so it runs at about 1.4mA and 7V in total.

No idea what the signal strength is; I shall merely assert that it would be sufficient, given an adequate coupling network.  The H-probe is a qualitative measure, after all.

Tim

[BreakingOhmsLaw]

Dipping my toe in the 1GHz+ club. [...]

Great job!
Love the ghetto H-probe 
Try cooling the tranny with cold spray for turbo boost (see above).

[herc]

...and tell us exactly what parts you're using...

Fair enough, here's what I used: http://www.cel.com/pdf/datasheets/ne3210s1.pdf

NEC's NE3210S01 is a pseudomorphic Hetero-Junction FET that uses the junction between Si-doped AIGaAs and undoped InGaAs  to  create  very  high  mobility  electrons.    The  device features  mushroom  shaped  TiAl  gates  for  decreased  gate resistance  and  improved  power  handling.

whisper that text to a 68'is hippie, a goa-head or a modern psytrance kid, and he will instantly buy that little pill shaped thing

[KE5FX]

NEC's NE3210S01 is a pseudomorphic Hetero-Junction FET that uses the junction between Si-doped AIGaAs and undoped InGaAs  to  create  very  high  mobility  electrons.    The  device features  mushroom  shaped  TiAl  gates  for  decreased  gate resistance  and  improved  power  handling.

whisper that text to a 68'is hippie, a goa-head or a modern psytrance kid, and he will instantly buy that little pill shaped thing

They had me at the Infected Mushroom gates...

[BreakingOhmsLaw]

You know what is really overrated in electronics these days? Components. Who really needs them?
All you need for 300MHz is a transistor.

[SilverSolder]

LOL that's minimalist! 

[PA0PBZ]

I bet that would not work without the breadboard though

[JPortici]

I'd noticed a simillar thing happening with just a BJT and two resistor (base to VCC and collector to VCC).
At the emitter you could see an oscillation of decent quality (depending on VCC) at about 137 MHz
I didn't submit it because i thought it was just picking up some RF, altough the frequency and shape was unaffected by my hand

[BreakingOhmsLaw]

I bet that would not work without the breadboard though

Absolutely. It is running entirely on the parasitics   

[PA0PBZ]

I did the same here but I needed a resistor not to cook the fet. (It died anyway half an hour later...)
https://www.eevblog.com/forum/projects/challenge-thread-the-fastest-breadboard-oscillator-on-the-mudball/msg3100288/#msg3100288

[mnementh]

I bet BΩL is powering it with a CV/CC power supply set quite conservatively.     BTW... I REALLY like his documentary photography. I don't even need my glasses to see what he's doing. 

mnem
 

[BreakingOhmsLaw]

I bet BΩL is powering it with a CV/CC power supply set quite conservatively.     BTW... I REALLY like his documentary photography. I don't even need my glasses to see what he's doing. 

mnem
 

You bet correctly. 1,45V 38mA.

[T3sl4co1l]

It was suggested to me that I join this competition with a ring-oscillator based contraption of mine, which I quickly reproduced on a breadboard.

So, let's have a look at my entry:

(Attachment Link)

As you can maybe make out, it is a three stage ring oscillator based on 2N3904 (chinese off-brand) and 390 Ohm load resistors. As a specialty, the output of each inverter (collector) is connected to the input of the next inverter (base) with an LED. So what can it do?

(Attachment Link)

When we apply 10V of bias to it, the LEDs will light up and it oscillates at a frequency of 35 MHz. As you can see, this design also follows the rule of a full 5V swing. The frequency suggests a tpd of 4.8 ns for each inverter, which is already "interesting", if you look up the storage time of a 2N3904 in the datasheet. Btw, with red LEDs this goes up to 55MHz, corresponding to 3ns. The same design is much faster on a PCB, so the parasitics of the breadboard take their toll.

Ok, but maybe that is not the most interesting part of this oscillator. Let's have a look at some X-Y plots where X is the input of one inverter and Y is at the output:

(Attachment Link)

At 10V we see a somewhat circular output, which suggests that the phase delay of this inverter is constant - as expected for a proper oscillator. However at 11.8 V we can suddenly see a convoluted path that almost looks random, but is clearly repeating - a limit cycle? Changing voltages further can transition from noise to different structured trajectory.

It looks like this simple circuit is acting as a chaotic oscillator. I though that was quite neat. You can find a longer write up here: https://hackaday.io/project/170697-evaluating-transistors-for-bipolar-logic-rtl/log/179154-using-a-led-as-base-resistor-chaotic-ring-oscillator.

Congrats getting featured on HaD https://hackaday.com/2020/06/23/chaotic-oscillator-from-antique/

Tim

[PA0PBZ]

It looks like this simple circuit is acting as a chaotic oscillator. I though that was quite neat.

That is total chaos! I built the circuit with 3 x BC547c and wow! I have to raise the supply from 4V to about 4.8V before the world turns crazy but then the reward is big.
Also checked on the SA, there the baseline just rises well up to 200MHz.

[herc]

another neat oscillator:

http://www.totalitaer.de/Rftechnik/mikrowellensender2.htm

[SilverSolder]

another neat oscillator:

http://www.totalitaer.de/Rftechnik/mikrowellensender2.htm

(Attachment Link)

That's funny, I was just thinking if a multivibrator type circuit could be made to work at RF frequencies...   Looks like the answer is "Yes"!

[herc]

yes, interesting, isnt it ?

and by intuition i guess that this oscillator - though it needs more parts - has a much higher output power than the single transistor designs. what do you think ?