Any luck purchasing YIG Tuned Oscillators from Ebay?

[HarryGT]

Hi all! First post!

I am interested in playing, uh... I mean experimenting, with some YIGs. Ebay has plenty of second hand YIGs available, and I am wondering if anyone has had good success purchasing YIGs from Ebay? Any gotchas that I should look out for?

I have yet to see a post that actually shows the YIG working. Perhaps I am expecting too much.

The OP from this post got one to work. I might just end up buying one, and seeing if it works or not, but I thought I would ask around first!

Harry

[edpalmer42]

I didn't know anything about YIG oscillators, but they looked like they'd be fun to play do serious experiments with.  I've bought 4 oscillators, 2 filters, and a synthesizer built around a YIG oscillator.  They all worked.  The oscillators are a cheap way to generate very high frequency signals at rather high levels (+10 to +20 dBm).  Mine cover the range of 1 - 12 GHz.

It's best if you can find data on a unit.  The supply voltages are all non-standard and different from model to model.  FM coils are a nice feature (not all units have them), particularly if you want fine frequency control or want to use the oscillator in a synthesizer.

Make sure you know the difference between a YIG oscillator and a YIG filter!  If there's more than one SMA connector, it's almost certainly a filter!

Prices have been rising lately, but there are still good deals out there.  Filters are cheaper than oscillators.  Units with a driver are more expensive than units without, but info on units with drivers seems to be harder to find.  The drivers make it more convenient, but aren't really necessary.

A few years ago I threw together a zip file with various documents on YIG oscillators.  Help yourself.

http://www.mediafire.com/file/6v0db7crbkbb943/YIG.zip

Ed

[DaJMasta]

They do age and the signal strength degrades over time and they are susceptible to shock and static, that said, most of the ones you'll find on ebay are probably salvaged pulls and won't necessarily be bad.  While you may not find many that demonstrate them working, you will probably find some sellers who at least warranty against DOA.

If you haven't already, it's also worth looking into what is required to drive a yig oscillator - it's not just a rail, you need constant current sources to drive the tuning coils.  That means without building up a circuit, it could easily 4-5 outputs from a good bench supply to cover all the inputs and just get it running normally - and a couple would need to be in constant current mode.

Not a huge deterrent, really, but you want to be sure when the thing arrives that you'll be able to start playing experimenting with it.

[HarryGT]

Good advice from both of you. I think my game plan moving forward is to: see if I can find a YTO that has some data available, see if the seller has warranty, and then make a purchase. I didn't consider the lack of available info on some of them, since they're not really standard COTS parts! I think the availability of datasheets online has spoiled me!

Make sure you know the difference between a YIG oscillator and a YIG filter!  If there's more than one SMA connector, it's almost certainly a filter!

While my intent was about YTOs, I am interested in both (I don't know much about YTFs to be honest). I like the idea of a tuned BPF, with what I am assuming/hoping has a high Q, in the size of a YIG package - much better IMO than a bulky cavity all things considered.  I would have a good laugh if I bought a YTF accidentally!

A few years ago I threw together a zip file with various documents on YIG oscillators.  Help yourself.

http://www.mediafire.com/file/6v0db7crbkbb943/YIG.zip

This is awesome!! Thank you!!

If you haven't already, it's also worth looking into what is required to drive a yig oscillator - it's not just a rail, you need constant current sources to drive the tuning coils.  That means without building up a circuit, it could easily 4-5 outputs from a good bench supply to cover all the inputs and just get it running normally - and a couple would need to be in constant current mode.

Not a huge deterrent, really, but you want to be sure when the thing arrives that you'll be able to start playing experimenting with it.

I have already looked at a couple of documents online detailing the construction of YTO drivers. It would be nice if the driver came packaged with the YIG, but on the other hand I wouldn't want to deprive myself of some serious fun building up a driver!

[edpalmer42]

It's likely that a YTO with good data available will cost more than an undocumented one.  They're not that hard to figure out.  There's the main tuning coil, probably an FM coil, a heater, and one or two power connections.  Some power is plus AND minus, others are plus OR minus.  Put some current through the main coil, fiddle with the power voltages until an output appears.  I've successfully figured out a couple of undocumented units.  YMMV.

For initial testing, don't worry about a driver for the main coil.  Add a big resistor in series with your power supply and crank it up.  It works fine.  Depending on the model, you might need up to half an amp or more of tuning current.  If your power supply has good constant current control (mine doesn't), the resistor isn't necessary.  Just go with constant current mode.

The FM coil is a different matter.  The wire is very small and delicate.  I recommend a driver for anything involving the FM coil.

Ed

[HarryGT]

Ed,

Thanks for the advice! I will probably end up purchasing one soon, and take it into work to play with it!

[medical-nerd]

Hiya

Why not try one of the Stellex beasties?
You can get them alone or with with a controller board for which a lot of information and projects are available :

http://www.thegleam.com/ke5fx/stellex.htm

or if you want to build your own driver board using one of these:

http://www.qsl.net/kb9mwr/projects/uwave/Experimenting%20with%20a%20Stellex%20YIG%20Oscillator.pdf

Cheers

[HarryGT]

Hiya

Why not try one of the Stellex beasties?
You can get them alone or with with a controller board for which a lot of information and projects are available :

http://www.thegleam.com/ke5fx/stellex.htm

or if you want to build your own driver board using one of these:

http://www.qsl.net/kb9mwr/projects/uwave/Experimenting%20with%20a%20Stellex%20YIG%20Oscillator.pdf

Thanks for the reply!

I have actually seen both of those links while hunting around for information about purchasing YIGs - I hope that those links serve any future viewers well!

A quick search on Ebay brings up a couple of Stellex YIGs that are slightly above my range of interest. Im primarily interested in ~2GHz - ~6,~7, or ~8 GHz. Most of the Stellex ones sit around ~9GHz or above, and don't dip as far down as 2GHz.

I have thought about grabbing one of those driver boards, but I also wouldn't mind building my own driver board just for the fun of it. The Stellex boards already have an integrated PLL to lock the YIG against whatever which is a major plus. Much to consider.

On another note, this one is 12GHz - 20 GHz for $125 USD!!! Heck I might buy one of those just because its so wide band (wide band relatively speaking, but the price is good for the range)! Get 'em while they're available!

[Teledog]

COMPLETELY off topic (kinda?)
Have a YIG (oscillator) and a YAG (laser)
Thought of making a YIG and YAG T-shirt (a la: Yin & Yang?)
Totally geek... doubt many people would get it..
Might be an interesting graphics project...
/end geek