RF Metrology

Hard to tell. How big are the whoopdedoos, and roughly where?

Posting a screenshot would help.

Cheers

Phil Hobbs

What specific tiny SA did you buy? How's the image rejection?

Connectors can cause passive harmonic and IM distortion. That's a big deal in cell phone towers.

Aren't we getting a teensy bit lazy?

Jeroen Belleman

I have seen transmission (S21) losses of around 1dB at about 1.2GHz just from failing to tighten an N connector sufficiently. We do need to know the magnitude and frequency of the problem in order to give helpful comments! John

Not really. If you just think of it as a slight impedance mismatch in the cable between the SA and the signal generator. However, this model has the facility to be able to save files of the screen display (although I very much doubt it'll save a real-time video of the sweep). And John - it's the 'Ultra' version. I already had the base model and this is a worthwhile upgrade. Jeroen - it's more a problem of available time!

I collected some TDR traces of various connectors, adapters and terminators a few years ago:

After having seen what LEMO-00 hardware did to my signals, I was pleasantly surprised by the performance of SMC.

SMA was the best I had around, hands down, no surprises there.

Jeroen Belleman

Ultra what? Got a link?

SMBs are surprisingly good, and easier to use.

Shining Star makes nice, crazy cheap, edge-launch SMAs and SMBs.

Yes! That is what I believe is happening. Nothing much occurs between

It has its own home page:

Measurement of good vs bad cables:

Very precient of you, Klaus. I was just about to ask about others' experiences of cheap Chinese RF connectors. I'm reluctant to hook them up to my expensive Western analyzers in case they get damaged by poor fit or some such issue. I have to say, though, that the only issues I've heard about in this regard are damage to the Chinese connectors' center pins (being pushed in) during insertion. I could live with that, so long as my expensive test equipment remains unharmed.

I solved a billion-dollar showstopper last year. Some country started demanding that some expensive semi fab gear be EMI tested, and our units failed. After great hassle we traced it to bad ground crimps on shielded CAT5 cables that our customer bought cheap.

I bought a set of phase-matched cables from Taiwanese company JYEBAO because my usual supplier Huber & Suhner failed to answer a quote request. I was pleased to find that JYEBAO's cables were *better* than H+S, and cheaper too.

Jeroen Belleman

So ar, the generic cheap Amazon SMA and SMB cables have been excellent. As have been the edge-launch connectors.

The Shining Star connectors are great too.

Probably made next door to each other, or in the same sweat shop on different days.

RL

I don't think so. I compared H+S matched sets with JYEBAO's and there were clear differences. The JYEBAO cables were clearly better matched, and of overall better quality too.

Another positive experience I had with them concerned the delivery of cables with a 75 Ohm C connector at one end. Nobody makes 75 Ohm C connectors anymore, but they delivered.

Jeroen Belleman