Connectors from Chinese/Hong-Kong/Taiwan, etc  - Page 1
Forum section: electronics / rf-microwave

author: tkamiya
author_rank: Super Contributor
timestamp: August 22, 2018, 06:35:43 pm
content: I know the correct answer is, buy from a reputable company and there will be no such problem. I know, but budget constraint makes this endeavor worthwhile.....I buy lots of connectors from eBay, and most of them are made in China of its "affiliates". As such, there are no datasheet available. Most of what I buy is crimp type. I have N, BNC, SMA, SMB, and few others. Frequency range that I deal with are up to 2GHz so, it's NOT THAT critical. But, I'd like to get what's available in performance in these less than ideal conditions.With well known manufacturers, there are stringint measurement requirement when stripping coax. How do you do this with these connectors? Follow similar one from well known places (where the company likely copied from) and see what happens?

author: rhb
author_rank: Super Contributor
timestamp: August 22, 2018, 09:45:07 pm
content: I think that it's "make a cable and sweep it" . I bought a pile of adaptors and such and have discovered several that don't work. So I shall have to test them all :-(What really bothers me is the SMA board edge connectors. How does one test those before soldering them in place?

author: Pinkus
author_rank: Frequent Contributor
timestamp: August 22, 2018, 09:53:37 pm
content: it depends: if you can be prosecuted afterwards for the product or for damages or liability, then I would always use only connectors from known manufacturers purchased from reliable distributors.I know, buying cheap on Aliexpress or Ebay or directly can be tempting as of the saved money, but keep in mind, that if a problem occur, a court will convictyou, because you as an expert must know that cheap china connectors are (probably) worse than the ones from reliable manufacturers.Of course for just a DIY hobby product this is different, but if you are talking about a real product you want to sell, I would not go the cheapest way.

author: tkamiya
author_rank: Super Contributor
timestamp: August 23, 2018, 02:45:04 am
content: This is strictly for personal enjoyment.

author: mark03
author_rank: Frequent Contributor
timestamp: August 23, 2018, 03:07:18 am
content: Quote from: Pinkus on August 22, 2018, 09:53:37 pmI'm not sure there is a difference. As a hobbyist I find it difficult to justify the hassle of sourcing non-reputable parts. Maybe I am just slow, but actual parts cost for my projects is utterly dwarfed by the hours spent designing, building, and testing. I don't value hobby hours the same as work hours, but that time is still worth *something*... at least a few $$ / hour? My tab at Digikey is not even close to my largest hobby-related expense. If you are only building one or two of something, why skimp?This does assume a middle-class lifestyle in the West.

author: xrunner
author_rank: Super Contributor
timestamp: August 23, 2018, 03:15:30 am
content: Quote from: tkamiya on August 22, 2018, 06:35:43 pmWell I can speak to the performance ... of the machining of cheap Chinese BNC connectors. They aren't all right. I've thrown away quite a few that just will not connect to test equipment that I trust has BNCs with correct machining such as hp or Rigol. I've examined these poor connectors and it's obvious they are machined differently from "standard" BNCs. I don't know why they do that but it's a bad idea.

author: Bud
author_rank: Super Contributor
timestamp: August 23, 2018, 03:44:20 am
content: Quote from: tkamiya on August 22, 2018, 06:35:43 pmThere is a danger with mechanical tolerances being out of spec, meaning you can damage your equipment industrial connectors when mating with these chinese made ones. A mitigation measure is to have saver connectors on your equipment and only mate the chinese connectors with them, not directly to the equipment. Or use chinese on chinese connectors.On some of SMA chinese connectors I saw the dielectric popping out of the barrel with slight pressure or even pulled by the mating connector with it when unmating. That was funny.That is even before spending efforts on trying to measure them.

author: tkamiya
author_rank: Super Contributor
timestamp: August 24, 2018, 03:52:41 am
content: Yes, I do use connector saver - which is a good grade Amphenol.I guess I'll have to figure out the measurement myself. I know most won't agree with my purchase decisions.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 24, 2018, 05:07:46 am
content: When I started I got chinese connectors too. But I have long decided that I won't be getting any more of the cheap connectors. It is just not worth it, in my opinion.SMA connectors can be had for a few bucks from reputable sources that work well to a few GHz. Sure, it is not going to give you amazing performance up to 26 GHz, but it will work pretty well.But if you really want to use those connectors - I assume they based their design of of a other product. Find that product, use its datasheet.

author: BravoV
author_rank: Super Contributor
timestamp: August 24, 2018, 06:39:53 am
content: Just let the photos tell the story, bought these while ago, N male to male adapter, AliExpress vs Amphenol. Hint, take a look the wall thickness.

author: tkamiya
author_rank: Super Contributor
timestamp: August 24, 2018, 05:24:34 pm
content: Gentlemen,Thanks for the warning. I am aware of all this. I am using them knowing the risk. I experienced some of the deficiencies myself. Of course when something is critical, I am using known-good supplies from well known companies. I have few instrument grade stuff reserved just for some occasions as well. All I wanted to know was, if there was some kind of resource for those "clones" so I can install them properly without guessing.I am going to cut one of each in half and take some measurements.By the way.... I had a few Amphenol stuff that were bad recently. It must have been a batch failure because all 5 of them purchased at the same time were affected. Of course, seller, Digikey, gladly refunded my money. I'm sure that's a rare occurrence. But since then, I leaned to not blindly trust anything. Since then, I make good use of test signal port and tracking generators. Just to make sure there aren't unexpected.I leaned few new things since I started meddling with high(er) end equipment. One of my big concern is, connectors on equipment. It doesn't take much to damage those center pins. That's why N to BNC by Amphenol stays there pretty much permanently. Sort of like condom for SpecAn.

author: Lord of nothing
author_rank: Super Contributor
timestamp: August 26, 2018, 10:52:06 pm
content: I need some SMA Plugs my self. Is there an European Shop who offer cheap Shipping and have legitimated Product?the Problem is when I looking for European Shops the have often huge shipping Cost from 30€ - 50€.

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 27, 2018, 04:09:34 am
content: Quote from: Lord of nothing on August 26, 2018, 10:52:06 pmHave you looked at Conrad? I think I have used those in the past and shipping was acceptable.

author: xaxaxa
author_rank: Regular Contributor
timestamp: August 27, 2018, 05:34:54 am
content: Quote from: Lord of nothing on August 26, 2018, 10:52:06 pmmouser

author: Lord of nothing
author_rank: Super Contributor
timestamp: August 27, 2018, 10:42:29 am
content: Quotethe resell just the noname chineese crap.Even the "specialist" recommend them.Quotethx the have way to much.I will contact them.

author: mzzj
author_rank: Super Contributor
timestamp: August 27, 2018, 10:58:38 am
content: Quote from: Lord of nothing on August 26, 2018, 10:52:06 pmDigikey. If you go to their localized website they offer free shipping on orders over 50 euros.For austriahttps://www.digikey.at/My german is non-existent but if their delivery terms are same as to Finland they handle the customs fees and duties also.Distrelec could be another alternative to look for components, just be wary that their in-house brands can be crappy.https://www.distrelec.at/

author: Lord of nothing
author_rank: Super Contributor
timestamp: August 27, 2018, 11:05:17 am
content: thx below there are € 18,00 Shipping fee (for some connectors).QuoteIs Finnland not in the EWR or why does Customs fee are added?

author: mzzj
author_rank: Super Contributor
timestamp: August 27, 2018, 11:13:52 am
content: Quote from: Lord of nothing on August 27, 2018, 11:05:17 amI never have problem to fill the 50 euros minimum order on Digikey to get the free shipping(for example AA batteries are cheaper than your local supermarket)Digikey is U.S. based company so normally you would expect to pay custom duties and exorbitant shipping fees!

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: August 27, 2018, 11:53:03 am
content: Quote from: Lord of nothing on August 27, 2018, 10:42:29 amThey might resell noname chinese crap, they also sell brand-name stuff. I've gotten some H+S, Rosenberger, Telegartner and Amphenol RF connectors from them, because they are faster for me sometimes than Farnell (since Farnell goes through Uni, which means I have to go pick it up there).

author: Lord of nothing
author_rank: Super Contributor
timestamp: August 27, 2018, 12:02:05 pm
content: I send mouser an EMail what I need. There Shop is crap.