Coax Connectors

When buying coax fittings you get what you pay for. Cheap price sometime equats to cheap construction.

I've used times connectors (EZcrimp & soldered) and times coax (LMR etc) for about 10 years without any problems.

You can shop the connectors and coax all over the place, just remember that the times EZ-crimp with take about $70.00 in tools to install the connectors.

the connectors you saw at hyperlink tech are similar to the RF parts connectors. The center pin connector is crimped on the coax then the connector is assembled. I've seen people assemble this connector and because the center conductor of the coax had a little bend they ended up with a center pin off center when the connector was assembled. You won't have this problem with the Times EZcrimp version. the most common LMR you get into with wireless is LMR-400. These connectors are real easy to install. The rest take a little knowledge and alot of care. For the small coax I usually by the adapter coaxs ready made.

below are links to pdf's and a video about the install procedure.

below is a like to the pds's for installing times connectors

here's a video of the same thing -

hope this helps. Make the big ones, buy the small ones and spend time making it work instead of beating your head against the wall trying to manufacture the small adapter coax.

Bob Smith Robert Smith Consutling Wireless - ISP's - Government - Business

NA6T life Member ARRL

One of the demonstrations I like to give at radio club meetings is to take all the coax cable adapters in my collection, place them in series, install a watt-guesser at each end of the string, and connect it all to a transmitter and dummy load. I then ask the audience to guess how much loss 6ft of connectors is going to show on the wattmeters. Also, the VSWR. I usually do this at 440Mhz, but have also done it at 1.2Ghz. Unfortunately, I haven't done this test at

2.4GHz. According to the orthodox advice, adapters and connectors are lossy. Wanna guess the loss through about 100 random coax adapters?

The answer is about the same as an equivalent length of RG-8/u coax UHF or phono adapters). I don't worry much about connectors. It's the coax cable that eats the power.

However, there's one thing that is missing in the above demonstration. There's no consideration for the quality of the coax connector to coax cable connection or crimp. This is where literally every single connector failure I've seen occurs. Manually assembled, non-crimp type connectors such as the common UG-21 N-connector are an invitation to eventual failure. Wiggle it enough, and the braid just seperates inside the connector resulting in a crappy connection. All my test and production cables are crimped. So are all commercial patch cables and pigtails. This is especially important in the smaller connectors (smaller than SMA) where there's very little braid or foil to clamp in the connector.

Another quality consideration is VSWR. Let's pretend I screw up and use a 75 ohm cable and connectors instead of 50 ohms. That's not the same as using a "low quality" connector, but is a fair simulation of the results. The loss is actually LESS for a 75 ohm system than with an equivalent length 50 ohm system, because the RF loss per foot at

2.4GHz for 75ohm coax is less. mismatch loss for the 50 to 75 ohm transition (VSWR=1.5:1) is only 0.18dB. Translation: Don't worry about the alleged impedance "bump" created by a "low quality" connector.

So, what consistitutes a useable "good" connector? Methinks (in order):

1. Power handling capeability.
2. Corrosion and environmental resistance. Waterproof.
3. No dissimilar metals. Electrolysis prevention.
4. Crimping ability and quality.
5. Mechanical strength.
6. Decent electrical characteristics.

Details:

1. Power handling capeability. We can ignore this at 2.4GHz unless your running high power with high RF voltages.

1. Corrosion and environmental resistance. Waterproof.

1. No dissimilar metals. Electrolysis prevention.

These are the real killers. I've cleaned up a few products that were a mixture of gold, silver, solder plate, zinc, and tin plated connectors. Add water, salt, and a little DC and you'll shortly find either corrosion or watch the plateing disappear. In extreme cases, the mess forms a diode or battery causing RF problems. Whatever you do, avoid incompatible materials.

1. Crimping ability and quality.
2. Mechanical strength.

That means the crimp joint is both mechanically and electrically stable. It should be able to pass the pull, twist, and bend test without falling apart. It should also be cosmetically reasonable. The current trend is for the connectors to be minimalist and just extensions of the coax cable. This makes sense, but also tends to create flimsy connectors, especially the stamped connectors.

1. Decent electrical characteristics.

VSWR and loss. At 2.4GHz, this mostly consists of making sure that there are no resonances introduced by the connector. The frequency versus VSWR plots usually reveal any such problems.

So, who are the quality vendors? Well, that varies depending on what you're trying to build. The list is huge because literally, there are no "bad" vendors. AMP, Hirose, RF Industries, Amphenol, all make good connectors. If you're doing CATV (75ohms), the vendor list expands greatly. What is a problem is bad selection of connectors. SMA connectors from multiple vendors are all standardized and almost identical. Concentrate on the connector to coax connection (crimp) and the rest will take care of itself. For example, the common CAT5 "hex" crimp connectors are really marginal, while the same F-connector with a "push on" connector is both waterproof and mechanically superior.

Try Electrocomm and download their latest catalog:

cables and connectors. If you're building your own cables, plan on spending some money on crimp tools. I probably have about $500 worth of coax crimp tools. The factory crimpers are expensive, but the clones are now affordable: (under hand tools) (HT-301x series of crimpers)

What do you use for stripping the LMR-400? I have a small collection of plastic strippers, all with dull razor blades. The typical stripper will last for about 20 connectors. Replacement blades are advertised but always out of stock. The CATV strippers that I often use won't adjust to the LMR-400 diameters. I currently use a pocket knife and diagonal cutters, but that's too much work. I've considered making my own but that's rediculous.

Not me. I have a different way to do it wrong. I crimp the connectors, at each end, while the LMR-400 is tightly coiled. When I straighten the coax, the center pins protrude excessively.

Another great mistake is to believe the data sheet and assume that all types of LMR-400 are exactly 0.405" in diameter. I have some rubber jacket ultra-flex LMR-400 that is actually 0.415" in diameter and will just barely fit into the crimp ring sleeve for the RF Industries connectors.

Agreed. They are great connectors. However, EZ-Crimp connectors are expensive at $13/ea versus about $3/ea (N-male to LMR-400) for the more common crimp connectors. See:

carries both types.

So where do I get the best deal on them? I am having a hard time even finding the Times Connectors anywhere.

Assuming you want LMR400 and N-male, I've had good luck with a bunch of N connectors I bought for a deal off eBay. Search for "LMR400 connector" and there's some for sale now. Belden brand, I'm not sure that's the same product that I bought but looks similar. The ones I got came with nice heatshrink that comes way up on the connector and down on the cable, nice way to waterproof that part of it. I got the crimper from

You can get top quality coax for 2.4Ghz and above from here.

He posts to anywhere in the world, take a look at the Ecoflex range.

Note the EcoFlex-10 N type connectors fit LMR400

-- JM

Holiday Greetings!

You mean something like the old Ideal 45-51x series? We used to buy the replacement blades direct, and in fairly large quantities. That would last for a while, but they aren't perishable.

Klein Tools used to make a relatively nice one - I managed to loose the last one I had about five years ago. Last time I looked at their catalog, I didn't see anything similar. Pity.

For hard line, OmniSpecta used to sell a steel block about 1 inch cube, drilled to exactly fit each coax, with a slot on the side for a hacksaw type blade (48 teeth/inch). The idea was that you sawed to the full depth of the guide slot, rotated the cable a quarter turn, and repeated. This resulted in nearly all of the dielectric cut (you'd finish with an Exacto blade while twirling the coax in this fixture), and the center conductor untouched. Hate to think how much Times Alumifoam I wasted by nicking that center conductor. I don't think the idea was patented, but we had the shop build a family of those blocks for all the hard line we used, from 0.085 RG405/U up to 1 inch air line. We also had similar blocks made to allow cutting the jacket without touching the outer (aluminum) conductor of Times Alumifoam and Alumispline hard line.

Old guy

Bah humbug. Why does it always rain on holidays and vacations?

$10/ea for a replacemnt cartridge. It's one of the strippers I have in the pile. I recall that these last about 20 connectors maximum for LMR-400. That's $0.50 per connector in blades, if I can find the blades. With a dull blade, I can do it faster and better with my pocket knife and diagonal cutters.

I looked and didn't find anything. When I worked for Ma Bell in the stone age of telephony, we used only Klein tools. Best tools ever except possibly for the various Swiss manufacturers. Now that I have to buy my own tools, I can't afford $50 pliers.

I have some hex blocks that work that way. Unfortunately nothing for LMR-400. Most of mine are for various CATV cables. I've used these and they do work fairly well. I don't do the finish with an Exacto knife or razor. I have a few Teledyne thermal strippers to do the job. Once through the jacket, aluminium foil, and braid, it's all dielectric, which melts nicely (though smells awful). The thermal stripper prevents nicking the center conductor. The only time this doesn't work is with gel filled water proof coax (LMR-400-DB), which tends to make a huge sticky mess no matter how it's stripped. For those, I use a pipe cutter as I don't wanna spend the day cleaning my tools.

Use a hot wire. If you don't wanna spend the dollars on a thermal stripper, just get a roll of nichrome heater repair wire from the hardware store. Apply some current from an old plastic bag sealer xformer until it's hot. Strangle the coax with a loop, and pull. That's the way I do it in the field. The only cut that needs to be made is through the foil and braid. The center conductor and the jacket can be removed with a hot wire. The only reason I don't do use this for everything is that I keep burning my fingers, which wrecks my piano playing.

Yeah, that's what I was trying to avoid. However, I have access to a machine shop so I'll probably have them build such a block. I'll see if I can find some cheap steel rule die material for the cutters as I don't like ripping through the braid with a hack saw blade.

Thanks.

HI Jeff, long time no talk to,, hehe been busy, the hotspot business on the mendo coast is crazy, I've install 12 in the past 3 months, and got three more to go by the first of the year,, one is a goodie

AP ->to all rooms (almost -> CPE ->AP to the rest of the rooms

I'm using interepoch stuff, it's great

anyway, back to the times info, I've been using the times tools for about 4 years. I've got a set of tools for LMR400- & 600. two piece stripper, center terminal 'pointer', and crimpers. I get the blades from Electrocomm, they have to be ordered, your right, but I always keep a spare set of blades in the tool box.

your right on the coax, so what I do is always spec times cable. A contractor can do that, I usually get to spec out the parts to use in ALL my systems, so times gets the vote. Your right the connectors do cost more money, but the failure rate is NIL......

strip, trim, point, push, crimp, and melt the heat shrink, done job in

2-4 minutes,, and no comebacks, And the biggie is if your on a tower or roof you CANT drop the center pin,,,,, hehe

Bob Smith Robert Smith Consulting Fort bragg, California

snipped-for-privacy@painkiller.example.tld (Moe Trin) hath wroth:

They haven't. I goofed. The typical lineman's pliers and cutters are about $25-$35 mail odor. Add about $10-$15 if you want 1000v insulated handles. There are some $10-$15 rebranded cheapos mixed in. These are easy to spot because they don't have the Klein Tools name inscribed.

I used to buy from the local traveling tool truck, which tacked on another 50%. I didn't care because I needed the tools immediately.

Want to have some fun? Take some Plenum cable. That's the stuff that's suppose to go into air plenums so that the occupants don't get asphyxiated by noxious gases during a fire. Set fire to it. Compare with non-plenum cable. I like to do this with CAT5. Huge fire from the plenum cable but very little smoke. Slow burn from non-plenum with some smoke.

Q: What's the difference between tubing and pipe? A: Tubing always has the same O.D. no matter what the wall thickness. A: Pipe always has the same I.D. no matter what the wall thickness.

I'm not sure if coax cable is tubing or pipe. I would say pipe because the impedance is determinded partly by the I.D. of the outer shield. The wall can be any thickness and the impedance remains the same. Therefore, methinks it's a pipe cutter.

All my pipe cutters are dull thanks to automotive use. I peel back the outer jacket so the rollers don't make a mess. The big problem is that I have to deburr the outer shield in order to get it to fit the connector. The process also tends to leave metal shavings all over the dielectric face. I'm sure it can be done better, but the common plumbing pipe cutter is far from ideal.

I have a few of these: |

came from auctions and sales. They're the only thing that will strip PTFE wire properly. Lots of smog with anything else.

For field use, I have a 6V gel cell, rheostat, and chunk of nichrome wire. The trick is to remember to wear gloves or I usually manage to burn my fingers.

and beaten to death by me. I'm a lousy pianist, but I enjoy playing. Burned fingers also affect my typing and probably my spelling.

Rain? We had two showers in early November. Just be glad you're not in Seattle or on Kauai.

Newark used to sell the L9225 for about US$6, but that was a while ago, and I haven't priced things recently.

My first tool box, back in the 1950s had nothing but Klein pliers, and they weren't cheap then either. The exception were genuine ViceGrips rather than Klein-Loks. I didn't realize Klein have gotten _that_ expensive though.

The main problem is that they are heavy, and to specialized. I got away with it partially by not using that many different cables.

Polyethylene - probably not as bad as PVC, but I still don't like the gases.

Tubing cutter? When I started using hardline - that was the preferred tool (before those hex blocks), but the blade had to be sharp, and you had to take it slow, or you'd roll the end of the outer jacket and there went the VSWR. (Don't forget, I worked in the atmosphere were a 1.08:1 was getting marginal, and 1.10:1 was a reject.)

I don't remember the brand, but we had a thermal knife. If you were striping a lot of wire/coax in the shop, it was OK, but it certainly wasn't something that was used outside the shop.

What people won't do for the arts.

We mainly used it for hardline, and that required a saw (well, for aluminum, you could probably score the surface with a pencil and have it break for you), so these blocks were a hardened tool steel. Your tax dollars at work.

Old guy

Yeah, but what's in that smoke? COCl2 anyone? At Ames, we were prohibited from installing the standard (PCV jacket) coax on the research aircraft. That wasn't a big deal for a RG-58 sized cable, but was a lot more grief at RG214 sized stuff. In don't think the fire marshal ever looked at what we installed in some of the instrumentation racks on the ground. Probably would have had a heart attack.

Some call it hose, but I'll go with pipe too. Same reason. I learned the tool name from aviation heat/vent guys, so the name tubing stuck.

I only used mine on hardline, and once on standard copper tubing. I also replace the blade every couple of years whether it needs it or not ;-)

Why? At least with the tools I'm using, I don't see burrs,

That's a common problem with the hex blocks and saw, but I don't see it with the tubing cutters.

Old guy