Challenge Thread: The fastest breadboard oscillator on the mudball

[joeqsmith]

The columns of contacts will couple to others around them and they in turn will couple to ones around them.  It's not just between the two.    You would need to consider all of these paths.  Don't forget that the name of the game here is "fastest", not most stable, best matched, lowest distortion, lowest power draw, least parts used or lowest cost.  Even how clean it looks doesn't matter.  From what I understand, there's only the one goal. 

Personally, I wouldn't have any problems with someone mounting their breadboard to metal and using that.  As long as the contacts below are not connected DC wise to the plate as we already had that discussion, you should be all set.   

I'm also not apposed to what ever diode, transistor, FET you care to use or how you connect them.  Our host has already disallowed ICs but they did cover the resistors used internal to some RF transistors.   Some time ago, we had a new member going off about some strange new oscillator they had designed.   Something totally novel.  A few of us spent some time trying to help them along.  During that I made this video showing a simple oscillator running a couple of LEDs in avalanche.      If you wanted to use LEDs, I would be fine with it.   

[SilverSolder]

If the conical magnet wire LC circuits are alright to use,   I would then like to also use this same technique to couple to the output coax. I don't like putting DC into my test equipment if it can be helped.

How about using two adjacent rows?  Typically about 4pF.

Tim

The problem are each row has a lot of parasitics that you need to consider.   Mine is mounted to some plastic to get it up off the copper.  Our host has been pretty generous with the rules  and I wouldn't call fowl if someone mounted their breadboard to a half inch slab of Teflon.

What is the reasoning behind a conical coil?  (RF n00b)

[joeqsmith]

https://passive-components.eu/what-is-a-conical-inductor/

[joeqsmith]

I couldn't find anything with Dilbert talking smack  but I found this gem of Muhammad Ali        

[joeqsmith]

Go fast or go home!
https://www.cycledrag.com/nhdro-motorcycle-drag-racing-series-race-report

[joeqsmith]

Hard to say if it skirts the rules.  The conical coil was removed and the base is now tied directly to the feedback capacitor (the coil around the output).    All the magnet wire was trimmed down.   

[NiHaoMike]

Would a high voltage supply powering a tube used as an Xray generator be the highest frequency attainable on a breadboard? (I'm assuming just placing a gamma emitter on it wouldn't count because it's not electrical.) Actually building such a high voltage supply entirely on a breadboard is another problem, but it's possible - remove unused contacts to increase separation and submerge the high voltage part of the breadboard in oil. Or just build a Tesla coil using a tiny breadboard to connect the secondary to the tube in order to satisfy the requirement that all parts must be connected via breadboard.

[joeqsmith]

We are not allowed to remove contacts or cut them down or short between them below the board.  Basically, he wants the breadboard left original.

However, I see no reason that the supply would have to be built onto a breadboard anyway.   I'm certainly not including one. 

[joeqsmith]

A few breadboard videos that may be of interest:

[T3sl4co1l]

Would a high voltage supply powering a tube used as an Xray generator be the highest frequency attainable on a breadboard? (I'm assuming just placing a gamma emitter on it wouldn't count because it's not electrical.) Actually building such a high voltage supply entirely on a breadboard is another problem, but it's possible - remove unused contacts to increase separation and submerge the high voltage part of the breadboard in oil. Or just build a Tesla coil using a tiny breadboard to connect the secondary to the tube in order to satisfy the requirement that all parts must be connected via breadboard.

Why not run a Farnsworth fusor and make gammas too?

But as previously discussed, optical and such... aren't very easy to measure the voltage or waveform of.  Probably better leaving things in TEM0 mode, i.e., normal baseband electrical signals in transmission lines.

That does remind me though, I do have a reflex klystron or two; don't think any are higher than what's been shown here (just checked, one is merely 1450MHz).  It's basically self contained, so I could plug it into an octal base, modified (drilled out..) for the coaxial output electrode, which I'd have to hack by, like, just clipping an antenna onto it and sensing it in proximity with another wire going to my analyzer.  Anyway, the socket would have pigtails that plug into the breadboard, which would still meet the spirit of the challenge I think.

Unfortunately I don't have a negative high voltage supply to hand (it needs both positive plate voltage and negative reflector voltage); well, I guess I could use an isolation transformer and rectifier... mmh.  Rather not drill out a socket either.

Tim

[NiHaoMike]

Thinking about it some more, could a breadboard be used as the Xray source itself simply by placing it in a vacuum chamber? The power supply would be a Tesla coil, connected between opposite ends and residual air in the chamber would allow a tiny bit of ionization to happen.

But if "conventional" EM waves are the subject, the line between microwaves and IR is 300GHz. How close have hobbyists been able to get to that line?

[MiDi]

Interesting challenge!
Wondering what rules would be broken if a Laser-Diode is used.
The output power requirement of >0.3mW is easily achieveable.
I am aware that this is not the intention of the challenge

[SilverSolder]

Aren't breadboards pierced by gamma rays every day, just from the mere fact of being placed on Earth?

...Somehow this conversation is departing from the spirit of the challenge,  just possibly! 

@Joeqsmith has set the bar very high.  I can't even measure anything that high frequency!  I've never really been a super RF buff.  Maybe it's time to put something together as the first fumbling step...   How hard can it be etc. etc. (rabbit hole!)

[MiDi]

The term oscillator implies that it has a large coherence length - or in other words - the oscillation is continous and keeps nearly constant phase during operation.
This disqualifies all uncorrelated "noise sources".

[Berni]

Yeah i don't have any RF semiconductors laying around to make things this fast.

Unless perhaps a separate category is introduced for also furfilling the original 5Vpp output amplitude requirement. So something where the output could be used as a clock generator. Only problem with that is that it gives an advantage to people with active scope probes (the loading of a passive probe at >100MHz is horrendous due to its capacitance, so you might as well go 50Ohm at that point). But there is also the good ol DIY 1K into 50Ohm cable poor mans low loading probe, works surprisingly well.

[NiHaoMike]

Aren't breadboards pierced by gamma rays every day, just from the mere fact of being placed on Earth?

They wouldn't be generating the gamma rays, just (slightly) attenuating and backscattering them.

[SilverSolder]

Yeah i don't have any RF semiconductors laying around to make things this fast.

Unless perhaps a separate category is introduced for also furfilling the original 5Vpp output amplitude requirement. So something where the output could be used as a clock generator. Only problem with that is that it gives an advantage to people with active scope probes (the loading of a passive probe at >100MHz is horrendous due to its capacitance, so you might as well go 50Ohm at that point). But there is also the good ol DIY 1K into 50Ohm cable poor mans low loading probe, works surprisingly well.

Is there a simple/ cheap'n'cheerful way of measuring RF voltage?  E.g. would a simple 'rectifier+capacitor on a stick' concept work?

[BreakingOhmsLaw]

Great work and nice video! @Joe!

Bar raised to 6,3196 GHz!

[joeqsmith]

Thanks for allowing these latest changes. 

This is a link to an old RAP article on breadboards:
https://www.electronicdesign.com/archive/article/21770186/whats-all-this-smwisicdsi-stuff-anyhow

[Berni]

Is there a simple/ cheap'n'cheerful way of measuring RF voltage?  E.g. would a simple 'rectifier+capacitor on a stick' concept work?

I have seen people use single wave rectifiers to measure RF with a multimeter. Not sure how accurate it is over the frequency range, but I'm guessing it could be pretty good if a fancy RF diode is used along with careful RF layout. For it to be accurate you would probably need to characterize the linearity for amplitude and frequency (So means needing RF test gear). But to be able to tell there is 5Vpp of signal it would work.

You still need test gear to check the frequency of your oscillator anyway. So at that point its easier to just make your own "low loading probe" by soldering a 1K on the end of a 50 Ohm coax like so: http://jahonen.kapsi.fi/Electronics/DIY%201k%20probe/ Its really easy to make and can apparently work past 1GHz while still looking pretty much like a 1K resistor + some parasitics. Since it has a lot of attenuation also means that it can look at a very large signal before it would overload the input of a spectrum analyzer. I used the trick before and it really does work well. Never compared it to an actual active probe tho.

[joeqsmith]

Guessing home made wires are fine to use.   

[SilverSolder]

Guessing home made wires are fine to use.

LOL, you know when you start making your own wires, you are getting picky! 

[rsjsouza]

Here I was, assembling my BF494-based RC oscillator directly from my ancient FM transmitter circuits, when I stumble upon joeqsmith's 6GHz voodoo contraption. KO!

[capacitor_explosion]

Hello everybody,
At first I thought that more people would join in on the fun and take part in the challenge but sensei joeqsmith did an amazing job with his oscillator blowing my mind at firs but i was not going to quit  .
So this is my entry in the challenge , I have designed a Colpitts Oscillator emitter follower by the suggestion of my friend and eevblog forum member Mazo  .
         Measured with a Siglent SDS 1104X-E (non hacked ) 100Mhz oscilloscope .
•   All the connections to the board are made with the breadboard .
•   The transistor is TO-23 with soldered extension pins to fit in the breadboard .
•   And I have an smd 0603 100nH CCFH inductor with soldered extension pins.
Other components are typical thru hole .
.  Frankly speaking the signal is decreased significantly but still able to observe 90Mhz sine wave . I have glimpses of the signal going to 350mhz but I cannot catch it on shot . However I’m not giving up just yet . Maybe next week I will return with a more beefier oscilloscope and presumably a faster signal .

[BreakingOhmsLaw]

Great job! Now try using SMD resistors instead. These through-hole carbon resistors are basically a carbon coating with a spiral cut into it.  Thus, they have significant parasitic induction since it's shaped like a coil.

Of course, one could also abuse that particular property to his or her advantage...