Low cost coax connectors

Oops, sorry. But I did have callouses on my fingers from it ;-)

Nope, just cheap when it comes to designing electronics. The clienst like that :-)

There are good, cheap ones around. Most PCs, mp3 players, and ipods use the 3.5 mm version. We use them as RS-232 connectors on several of our products and they work fine.

Use MCX if you really want quality, at 10x the price.

John

Joerg hath wroth:

Too easy. I thought this was a low cost design, where every extra component saved is important. I've seen designs with DC on the antenna jack in order to save the cost of the capacitor. However, the power jack as an antenna connector does present another problem. If the antenna is part of the FCC type certification, the FCC sometimes requires a "unique" coax connector to prevent users from substituting the antenna and violating the type certification. The reason I say "sometimes" is that there have been various rulings and variances that allow the use of not so unique connectors or connectors that were at one time unique, but are now commonly available. Anyway, using the power jack as a coax connector would certainly not qualify as unique as one could easily obtain one at Radio Shock. Same problem with the

Incidentally, don't forget to perform the basic antenna field test. That's where the customer grabs the unit by the antenna and swings it around while walking. It's a very common problem with HT's (handie talkies) and seems to be spreading to wi-fi wireless access points and other devices with rubber duckie antennas. If the connect can't support the unit when held by the antenna, it will fail this all important field test.

Well, you asked for something cheaper than an RCA phono connector pair and tinning the coax is certainly cheaper.

Joerg hath wroth:

Sounds like the typical CATV headend. There are tools for removing F connectors (and BNC/TNC) in tight spaces.

This is for systems, mostly internal connections. Actually DC would not matter here as long as a short doesn't fry stuff. So if it's the bias of a transistor it would be ok. Can actaully be helpful in diagnosing a broken connection.

It sure is :-)

I've had lots of grief with these. Mostly the ground contact not being reliable or producing a "crackle" when the connector is touched. RCAs never did that.

Nah. Maybe I have to go back to headers but the labor has skyrocketed so much. At least in Kahlefohniah.

True, but you still have to turn several times and since the screw driver handle has to swing around the cable you quickly get stuck. Then you'd have to engage-disengage a lot. Mostly the cables are all bundled. In my cases with good old lacing cord.

Looked at FAKRA connectors? They're basically SMBs for the automotive market.

John

Joerg, you continually regale us with engineering demands requiring one to five-cent parts, multiple sources, 20-year stable component lifetimes, high performance, etc. Would you be kind enough to tell us in some detail about a few of these products? What kind of products are extremely cost sensitive, yet carry normally-high-priced technical demands?

I'd probably be looking down the barrel of a Magnum if I'd tell ;-)

Seriously, it's all contract designs and the contracts (and ethics) forbid the revelation of details. Mostly I design medical stuff and some of that is marketed to end customers. So, for example, if you can buy a blister pack with two units it's like with those electric toothbrushes. The cost maybe $79 plus tax but that means that each cannot cost more than $5-10. When designing this stuff you really have to think hard whether to use that nice and convenient $1 uC in there and the answer will mostly be "nope". More than once has a sales rep walked away from here shaking his head but that's reality these days. It's why I keep telling folks like the processor guys at TI that if they don't come out with a 25c MSP430 they won't win many design-ins here.

Then, there are the disposable parts for big-ticket gear. Since this is often the bread and butter of the client the margins are super important. Every penny counts. Even on the big-ticket gear itself that is the case because the business models often follow this path: Unit is placed "for free", tied to a minimum of x/month gizmo sales over y months. Just like those "free" cell phones. Therefore, the big ticket system has to also be shaken for every penny because it lands smack dab on the boooks, in the amortization section. To the CFO that's almost like inventory and they don't like inventory. Remember that hospitals are no longer "anything goes" customers, they are under a lot of cost pressure.

Want an example where I seriously had my hands in the design? Here goes, hopefully your ticker is working fine so you never need this procedure:

Then sometimes I design non-med stuff. Here we as a high-cost country can only compete if our gear is a whole lot better in price/performance than some cheap product for the far-east. IOW, there has to be a serious reason before the consumer or industrial customer is willing to pay five bucks more. Only durability and performance count, usually. An example: An RF preamp that has a noise figure 0.5dB lower than everyone else and a 10dB higher IP3. That sells, even if it's $5 more. But it can't cost more in production than the cheap brand because our businesses are taxed a lot higher. This is a kind of challenge I really like.

Thanks! Now that's an idea. If anyone else is also interested here is a link:

I DID answer it, idiot. "At his specified 100MHz..."

Just like your remark when you suggested the audio jack... "should be fine at 100MHz..."

Are you trying to tell me that you were not talking about electrical characteristics?

You have to use the "security tool" that the cable boys use.

Essentially a 7/16" socket, ground down to a thin wall, and with a lengthwise slot cut into big enough for the cable to pass into.

Still, nesting a gang of F jacks together probably would be a pain on a PCB. You'd need a plank of Aluminum to mount them all on....

Plank's law. :-]

No... I meant that you are nuts for thinking you'll ever find a solution at that price.

Unless you are going to be buying a million pieces, that is...

Let alone the fact that he probably only wants to build two pieces!

Can't do that, usually has to be on the PCB. In some cases long term on a phenolic two-layer.

:-)

John Larkin just brought up one style that could fit the bill in terms of cost, have to find out next week:

That's the other thing I'll have to find out: How many million.

But then the client turns around and has oodles of them built.