Power rating of SMA connections?

theres something here

-Lasse

Where they claim 600W at 1GHz for SMA. Wowzers.

Thanks, Lasse. When extrapolating from 1GHz on down the SMA should take a kilowatt :-)

Yikes. Even 200W through this tiny connector would scare me.

And re-read the statement that the power handling capability depends on the quality of the connector -- they're trying to puff off _their_ connectors.

One of my engineering profs actually had lots of practical tidbits to dispense (he worked in industry _and_ academics). His wisdom on this sort of thing: if the manufacturer doesn't put that parameter into their data sheet, that means they're not proud of it, and it's crappy.

That became blatantly clear early on in that article :-)

True. I just need to know where on the crappiness scale SMA connectors are. Whether they can safely carry 50W in the shortwave band.

I'd be uneasy even at 50W. ...Jim Thompson

That would be about an amp, and at HF where there's not much in dielectric dissipation. Looks doable but I'd like to know for sure from some manufacturer. Seems I'll have to write . It's so tough to get an answer beyond the datasheet these days because often the real gurus have been laid off, retired or passed away :-(

his

.pdf

ake

on

is

eir

a datasheet like this:

-Lasse

Thanks. I had found some MIL versions like this but they are very expensive. I have written to AMP about their regular $3 series, will let the group know when they answer.

AR uses SMAs up to 100W at RF:

Cheers

Phil Hobbs

I can't tell you for sure but I've seen them used for up to 50 watts at 850 & 2100 MHz.

H.

you have to think about the worst case VSWR of the load as well.

the current can double, the voltage can double and power dissipation (loss) can go up 4x.

Mark

Well, we will have a very fast bridge and a controller that shuts it down in the case the VSWR goes loco.

Good idea. The active devices die faster than the connectors, for sure. The protection circuitry also makes solid state amps a pain for things like plasma chambers--you tune the match at low power, crank it up till you get a plasma, which detunes the match and the amp shuts down. It's not impossible, but it's a pain.

Cheers

Phil Hobbs

Cheers

Phil Hobbs

For plasma generation it may be better to design your own amps. Then you know the limits. Many things can be protected by artifical rails and diodes, things you won't find in the typical COTS RF amplifier.

If it's really bad and it is a one-off experimental setup use a tube amp. Tubes are very forgiving, even the occasional blue hiss between plate and other electrodes can be survived if the amp is designed right. Same for current. I've had plates glow bright orange and the tubes survived without noticeable performance loss.

This was on a commercial 8-inch tool (an Endura iirc) at IBM, where a couple of friends of mine had a bright idea for a new chuck design but couldn't figure out how to tune it up when they were done. Once we figured out what series capacitor to add to the tweakier of the two pi-network caps, all was as in the Ukrainian rowboat. (*)

Cheers

Phil Hobbs

The one with the secret stash of vodka under the front cover?

:-)

What secret? That's their selling point! And a source of national pride, of course--imagine all those German guys having to put propane-powered kegerators in _their_ rowboats. ;0

Cheers

Phil Hobbs