Challenge Thread: The fastest breadboard oscillator on the mudball

[cj]

For who thinks the marker pins are part of the 'black magic' NOPE it works also without them.


@joe : thanks for welcoming me to the 1GHz+ club.
The 8569B is a nice but old SA and goes up to 22GHz.

[ogden]

For who thinks the marker pins are part of the 'black magic' NOPE it works also without them.

It shall be noted that your >1GHz breadboard oscillator fully follows rule #3. Congrats!

[joeqsmith]

Proper attire for the occasion.   

For the wannabes. 
https://www.zazzle.com/classic_555_timer_chip_schematic_circuit_t_shirt-235193027808469926

[0culus]

@Joe:
Breadboard: Fixing it is fine, just don't damage or modify it. It should be reversible to a pristine breadboard again.
Kapton: Yes, all that's going to do is act as an dielectric in a ghetto capacitor, so that's covered by rules 5 & 8.
Ferrite: Yes, Rule 5 & 8 again.
Positioning jig: Absolutely, if that's what it takes. Not sure if a lump of metal near your circuit is going to give you trouble.

I've been soldering to the plugged in wires, melting the breadboard every so often.   Then there was a lockup meltdown... Sadly this old breadboard will never be pristine again.       

Thanks for clearing up my questions.

I plan to change over to using a small 3XAA battery pack.  I worry that one swipe with Tim's tail (our dog) on the power leads will end it.   

Now if LeCroy would just send me a 40GHz scope.   

Fortunately my cats have been (so far, knock on wood) leaving these experiments alone. 

I'd like a 40 Ghz scope too; I have plenty of monopoly dollars! 

Anyway, I was able to hit 660 MHz using the same circuit but a faster 1 GHz transistor I found in my box of toys, and adding a high tech "ferrite" (really the tip of a small screwdriver  ) to the inductor loop. I want to experiment further so I won't share until I've extracted every last MHz out of it.

[joeqsmith]

I really figured the cat took that knob from my scope.     She sleeps most of the time and doesn't cause much trouble.

I'm in the same boat, wasn't born with a silver spoon and no one accepts my funny money.       Maybe I could offer LeCroy exclusive advertisement.... Nah... that's sounding too much like work....   

I added an LED to the battery pack to try and remind be to turn it off.  Also shown is the new oscillator on the right fitted with one of the new transistors.  At least I can afford the parts.     Between the two oscillators is my chip of ferrite.  All sitting on the freq counter which is apart while I am trying to sort out how fast I can actually drive it. 

I see some gains with the ferrite but keeping things mechanically stable has been a problem.  Too bad the Revlon clear didn't work. 

I want to experiment further so I won't share until I've extracted every last MHz out of it.

      With Trash and now CJ catching up fast, it's time for you to get some better parts.  There's always room for more in the 1GHz+ club!   

[herc]

@cj: thats a crazy oscillator. if this transistor still oscillates, even though there is the breadboard capacitance all over the place, (and with that weird "shortcut" inductor / resonator / between collector and base), how can you ever built a non-oscillating amplifier with that thing   ?!?

[cj]

The circuit is basically a Pierce oscillator.
The base and collector are shorted (DC) but for this transistor as with many others Vce_saturated < Vbe.
With the 10k resistor the bias voltage is Vbe so the collector isn’t saturated yet and therefore the transistor works normally albeit at a low voltage.
I’ve tested this circuit at 3V and works fine. At this voltage the total power dissipation is about 0.7mW and the generated RF power is a small fraction of that.
If you want to build a non-oscillating amplifier with these types of transistors don’t use a breadboard.

[TheUnnamedNewbie]

I've been thinking if you could use a gunn diode and use the walls of two slots in the breadboard like a waveguide. Add a short a bit further back between the two same walls to make your resonant section of waveguide. Point horn antenna at it to measure frequency.

 

[mnementh]

joe, OTOH... This is all like watching Master Po and young Kwai Chang Caine discussing discipline in the rock garden... 

Playing with high speed parts is a lot of fun.  You should join the fun.

Ehhhh... I never was a very good engineer, even when I was paid to do it; too weak in the theoretical part and too strong in the hands-on part. Too much cannabis in the off-hours trying to keep my sanity in 1980s-90s corporate borgland deleted the rest to make room for Star Trek and Farscape episodes.



My idea of high-frequency gear nowadays is this... I'm more than content to be a spectator (and occasional commentary) here.   

mnem
 

[joeqsmith]

While your rules will not allow removing or cutting them, we certainly can skip over one to cut the capacitance down.  This helped.

It's really unstable.

Hint: The rules don't forbid shielding. Recycle some tinfoil hats.

Shield for the new oscillator.   For now, it makes a fit contact with the coax.   I would like to add some pins and plug it into the breadboard.   However, if I do this, I would stake it at the reference points only.   It does help with the outside parasitics.   Things like XYZ stages may have less effect..... 

The small part is a detector.   I can tell that the oscillator is running but that's about it.

[joeqsmith]

My idea of high-frequency gear nowadays is this... I'm more than content to be a spectator (and occasional commentary) here.   

Looks like my 189. 

[PA0PBZ]

Here's my try at a minimalistic setup. It took a while because I had to repair the counter first. I don't think it can go any higher without breaking the rule that every connection has to be made via the breadboard. (excluding the SMA, they don't fit well in the breadboard...) So 1 active element and 1 resistor, and if you want to be precise one cap to couple the signal to the counter. The tuned parts are all 'embedded' in the breadboard, that's why I doubt I can get it any higher. I'm sure the power is not there, it runs on 2V 2mA
And yes, the breadboard will never be the same 

[joeqsmith]

Here's my try at a minimalistic setup. It took a while because I had to repair the counter first. I don't think it can go any higher without breaking the rule that every connection has to be made via the breadboard. (excluding the SMA, they don't fit well in the breadboard...) So 1 active element and 1 resistor, and if you want to be precise one cap to couple the signal to the counter. The tuned parts are all 'embedded' in the breadboard, that's why I doubt I can get it any higher. I'm sure the power is not there, it runs on 2V 2mA
And yes, the breadboard will never be the same 

Congratulations and welcome to the 1GHz club!   You're very close to joining the 5GHz club.  That ones a bit more exclusive.   

If you have a way to check the upper frequency limit of your counter and what options it has, could you please post them.   I suspect that mine with no options will start to fold back around 21GHz.  In other words, it seems like as the frequency is increased, the displayed value will decrease.  But I don't have a good way to prove it.   

[PA0PBZ]

If you have a way to check the upper frequency limit of your counter and what options it has, could you please post them.   I suspect that mine with no options will start to fold back around 21GHz.  In other words, it seems like as the frequency is increased, the displayed value will decrease.  But I don't have a good way to prove it.

It doesn't have the power meter, nothing happens when I press the button and the box that supposed to sit behind the N connector entry is not there. I'm not sure about the 24 GHz option, but since the front panel says 18 GHz..? If you send me one of your breadboard oscillators I can try  Are there any other options I'm not aware of?

[mnementh]

My idea of high-frequency gear nowadays is this... I'm more than content to be a spectator (and occasional commentary) here.   

Looks like my 189.

   Good eye.

I had to pare my bench back to just the essentials when I came to the Great White North; everything here either fit in one technician's toolbox or was built/acquired after I arrived. There's a 6022BE bought almost a year ago "to get me by" when I need to do more than count the angry pixies; I keep looking wistfully through the pages of Kijiji & FleaBay for a real wigglescope but no joy at any price I can justify.

mnem
 

[joeqsmith]

The 24GHz option is really what I care about.   If you don't have that, then I suspect your counter would be similar to mine.    I had started a thread here:
https://www.eevblog.com/forum/testgear/hp-5342a-microwave-counter-max-freq-limit/msg3098932/#msg3098932

I don't have anyway to check mine which is why I asked.  I had bought this little amplifier at Dayton for a couple of bucks for the case and made a comb generator out of it.  This was connected to the RF generator, output was connected to a HP and into my counter.  It's very possible the signal is just too weak.

[0culus]

While your rules will not allow removing or cutting them, we certainly can skip over one to cut the capacitance down.  This helped.

It's really unstable.

Hint: The rules don't forbid shielding. Recycle some tinfoil hats.

Shield for the new oscillator.   For now, it makes a fit contact with the coax.   I would like to add some pins and plug it into the breadboard.   However, if I do this, I would stake it at the reference points only.   It does help with the outside parasitics.   Things like XYZ stages may have less effect..... 

The small part is a detector.   I can tell that the oscillator is running but that's about it.

Send it to me and I'll throw it on the 8566B 


Where do you purchase copper mesh to make shielding? I would like to get some for a variety of reasons. 

I still have those 5GHz transistors so I will probably do some more experimenting this weekend while I wait for stuff to come.

[joeqsmith]

Send it to me and I'll throw it on the 8566B 

Where do you purchase copper mesh to make shielding? I would like to get some for a variety of reasons. 

I still have those 5GHz transistors so I will probably do some more experimenting this weekend while I wait for stuff to come.

It's a sad day when you find your beloved equipment can't even look at a 50 cent circuit.      I may have to take you up on your offer to test it.  If only LeCroy would send me an old sampling scope...  

I get most of my mechanical parts from McMaster.
https://www.mcmaster.com/mesh

Now that PA0PBZ is nearing 5GHz, you need to start thinking about some 6HGz.      That, and you know all those people with their 10GHz labs we heard of early on are working on taking the lead.   

[temperance]

For those who don't own a fast oscilloscope:

https://en.wikipedia.org/wiki/Lecher_line

An more practical example:
https://hackaday.com/2017/02/07/using-a-lecher-line-to-measure-high-frequency/

There are some Gunn diodes available on Ebay...

[0culus]

Send it to me and I'll throw it on the 8566B 

Where do you purchase copper mesh to make shielding? I would like to get some for a variety of reasons. 

I still have those 5GHz transistors so I will probably do some more experimenting this weekend while I wait for stuff to come.

It's a sad day when you find your beloved equipment can't even look at a 50 cent circuit.      I may have to take you up on your offer to test it.  If only LeCroy would send me an old sampling scope...  

I get most of my mechanical parts from McMaster.
https://www.mcmaster.com/mesh

Now that PA0PBZ is nearing 5GHz, you need to start thinking about some 6HGz.      That, and you know all those people with their 10GHz labs we heard of early on are working on taking the lead.   

thanks for the tip on McMaster.

I just need to order a few things from digikey and minicircuits and I can shoot for beyond 10 GHz.  [edit] I have my carts ready, but not much point in ordering till Sunday at this point in the week.

[BreakingOhmsLaw]

I am guessing that cj's and PA0PBZ's entrys are variant of the Armstrong/Meissner oscillators running purely on parasitics.
For educational purposes, heres one i made. It runs at a measly 2,6MHz - DC really - but here you can see the magnetic coupling of the inductors. It's two coils wound on a small ferite toroid.
See:
https://en.wikipedia.org/wiki/Armstrong_oscillator
The capacitor is omitted in my board, the breadboard measures at 1.5pF between rows.
The real laugh here is that it runs on a voltage as low as 0,765 Volts, and yet outputs nearly 4,6V peak to peak. Black magic! It's really stable as well, hardly any jitter.
Looking at the board, one cannot help to think how the f**k this even oscillates   
Tranny is a BF256B FET.

[joeqsmith]

This makes me feel much better about my sinewaves.

[joeqsmith]

Taking the new oscillator for a test drive and blowing the old record out of the water and it's only in first gear idling...   

****

Added a scope shot to make it official.

[0culus]

Daaaang. Nicely done. And here I am trying and failing once again to get this stupid 2SC5227 to do anything. Wonder if I killed it.  I have two more...

[joeqsmith]

Beyond the the basic ESD, making sure the supply limits the current and your not exceeding any of the max ratings of the part sort of stuff, hard to say.   

I would have the supply dialed much lower than the 70mA/20V max it's rated for.    You could also bypass the breadboard until to see something work.