RF connectors smack down ... AliExpress vs Amphenol

[BravoV]

From the N type connector in the opening post it's somehow clear that we are not targeting at the 30+ Ghz range.

How does a N type connector for 30+ GHz looks like ? Or specific differences say compared to the one at the 1st post ?

Or I asked the wrong question ? Like at 30+ GHz, N type is not suitable anymore ? 

[dmills]

N type tops out at about 18GHz, the geometry is too physically large to work higher up there because multiple propagation modes become possible once the dielectric thickness becomes a significant part of a wavelength.

There is a reason the 3.5mm, and later 2.92mm and smaller connectors are used at high microwave.

Regards, Dan.

[TheUnnamedNewbie]

Two points: I never said "only applies at mmwave frequencies" , but that it becomes a major issue at those frequencies. But that does not mean that it cannot be an issue to consider at lower frequencies.

And second: from the replies to the op, I thought this had become a more general "is there a difference/what is the difference", instead of just covering the N connector.

But whatever, as usual I try to share some information about the topic and people get annoyed that it is not the exact type they were looking for, I'll just stop commenting.

[G0HZU]

Yep, but a reputable brand 1:1 is still VERY MUCH cheaper then sending a VNA back to Keysight/R&S/Copper Mountain to have the connectors replaced, and even a non preciosn one will save the wear on the connector.

Adding a hundred quid or so to the cost of a £50k instrument is hardly a big deal if it means you can avoid weeks of downtime while the thing is being repaired.

Regards, Dan.

Who here has a "£50k instrument" on his desk?

Where are the numbers, charts and other things that make this quantifiable? Right now it's just a bunch of people claiming things. Labs full of test gear and all we have to show for it are opinions?

If you mean >$50k when new I've got a few items that qualify.

I have to be very careful when introducing 'anything' into my workroom that has an SMA connector on it. I try and only use the very best brands of SMA connector (and cable) to minimise the risk of damage to my VNA connectors/cables and the Ecal module that comes with it. The Ecal uses Agilent/Keysight's PSC series 3.5mm connector and these are extremely fragile. I think the Ecal module cost £13k here in the UK and it can be trashed with a moment's carelessness with a cheapo connector that has a tolerance issue or any kind of surface defect on the centre pin. So I inspect any new SMA connectors/cables under a microscope before allowing them into the workroom. Even a tiny burr could cause problems.

You can see the Agilent PSC 3.5mm connector in the link below and how easy it is to damage it. I hate inspecting my Ecal kit for damage because it is quite stressful counting all the tiny petals within each PSC connector (4 connectors in total) to look for any defects.

For this reason I usually only use some very expensive Gore cables to connect to the Ecal module. A good Gore cable can easily cost $1k USD. But these cables can easily be damaged by items under test and pass on the damage to the Ecal module. So I try and do all my testing via known Suhner or Johnson SMA connectors.

Nearly all of my N type connectors/attenuators/cables are made by Suhner or Narda or HP. I have a few cheapo Amphenol ones but these only get used on cheaper test gear.

https://www.microwaves101.com/encyclopedias/how-to-not-trash-a-calibration-kit

That is what these are for, if you want to minimize wear on test gear connectors. Also seen them in the N type connector variant, used on some VNAs.

Those look like SMA RP (reverse polarity) connectors? The gender of the centre pin is swapped on one end of them.

[dazz1]

Hi
I have got to the end of this thread and all I have read is fluff and puff.  I am not interested in +30GHz gear or reading how much companies can charge for so little.

My old professor used to say if it isn't measured, it isn't true.
Show us the data.


Dazz

[rhb]

FWIW I made the mistake of buying a bunch of Chinese adaptors on eBay.  I've already discovered two defective ones.  As in no signal defective.  And others which are intermittently -30dB notch filters when swept from 100 KHz to 2.9 GHz.  I bought 10 BNC M-M jumpers which are useless for anything but 50 MHz notch filters because the manufacturer twisted the braid and soldered it to the connector shell.  The truly sad part was these were no-solder screw on connectors.

I'll test the adaptors and keep any that are actually usable, but I'll never buy Chinese connectors or cables again.

[xaxaxa]

From my experience taobao/aliexpress > ebay; on taobao the descriptions are generally correct and I have yet to receive anything defective. You can find decent quality RF connectors if you pick the right price range and read item descriptions carefully. All the connectors I've measured so far show <-30dB return loss to 2.5GHz. Ebay however is just full of garbage quality stuff so I don't bother with it anymore except for local items.