Making your own RF cables is a concept amateur radio operators fail to recognize. When you actually want something more than DC to pass through your cable, that Radio Shack education just doesn't cut it.
There are alot of people around that will tell you how to do something. I'd ignore these people and listen to simple math and physics.
Just because you've been doing something wrong for 30 years doesn't mean it's right!
Stay with manufactures/distributors that actually care for their customers, not just out to make a quick buck.
The key to making proper RF cables and installing your own RF connectors is to follow a few basic rules, in no particular order.
- Avoid those cheap, pre-made cables sold at hamfests and stick to the higher quality cellular/two-way radio cables and RF connectors. Well-educated people don't travel around the country selling scrap surplus. Their particular RF cable/connector/adapter quality will always be the poorest.
- Don't buy pre-made RF cables, RF connectors or adapters that are not sold in packages or bags!!!! The cables and connectors will be covered with dust, they'll of been banged around, the pins will be damaged, and the threads will be dented.
This is known to the vast majority of consumers, but there are alot of stupid people out there. Would you buy a pre-made RF cable if some fat slob was twisting and flexing the RF connector make sure it's soldering on right? NO! Because the twisting and flexing will have ruined the cable!
- NEVER use the PL-259/SO-239 style connector. Period. Not even for handling DC. These connectors are the absolute worst. If that's all you have, oh well I suppose...
When you buy PL-259s you are supporting terrorism!!
- Avoid nickel plated RF connectors. Nickel is a very poor conductor of RF current and these connectors will cause intermodulation problems, especially in a dense RF (repeater) environment. The nickel plating is also known to wear off.
- When soldering on a RF connector, always use alot of concentrated heat. It's better to hit the connector with a quick, high temperature soldering burst then to drag out the process with a low temperature soldering iron. That is how you end up melting the dielectric of the cable.
- You'll discover quickly that it's very hard to properly solder on a PL-259 connector with an UG-176/5 reducer because the reducer will act as a heat sink during the soldering process and will actually lower the temperature of your soldering iron tip. This is one of the major problems with those cheap, pre-made cables sold at hamfests. Low temperature soldering equals bad cable.
If you don't have enough heat, you won't have enough solder flow for a proper RF connector installation. Your RF cable will fail in a shorter time period due to stress caused by the flexing of the RF cable itself. There just isn't enough solder on the shield to form a strong, permanent bond to the reducer's body. This is, of course, common sense to anyone with a college education.
- Use heat-shrink, or some form of stress-relief, around the area where the cable meets the RF cable. This is the area of the RF cable/connector that is the weakest! The shield of the cable will open eventually due to the stress of the the cable/connector movement.
- Don't twist the non-rotatable section (pins) of the RF connector! Argh. I hate people that do that. Take the PL-259 for example. If you rotate the pin while removing or installing the connection, you'll break the center conductor of the RF cable! Duh. What do you think that pin is soldered to? This is the same for N and all other types of RF connectors.
Only rotate a RF connector by the section that is movable. Repeat that to yourself a few zillion times.
- Don't check your RF cables/connectors with a DC ohm/continuity meter! For example, on a PL-259 ground connection, just a single tiny hair of the coax shield may be soldered to the RF connector itself, and it will test on a DC ohm/continuity meter as a GOOD connection. Well, it's not! It's actually an inductive component at RF, and the cable won't work the way it's intended too! This is, of course, common sense to anyone who doesn't breathe through their mouth.
These are only of few of the most important rules. There are probably hundreds more. If we all keep following these, hopefully we can put a few crappy RF connector suppliers out-of-business.
If you have access to the cable, use RG141 or RG142. Teflon and double shield. One is stranded center, the other solid. Can't recall which is which. The rest of the cable's construction is the same between the two and their specs are nearly identical. The nice thing about these cables is the double silver plated shield and high power rating compared to RG58 or even 214. Thus they are VERY stable with very low incidence of intermod.
Velocity is 0.66. So the cables WILL be longer.
Otherwise, on all other points, I agree. Use the best connectors. Typically Amphenol. Stay away from imports and others which you can't verify the insulator is Teflon and the plating silver or nickel. This is where saving a few bucks is a BAD idea.
Solder EVERYTHING. With 141 and 142, you can heat the cable up good and hot and flow the solder on the shield. Makes for a VERY durable and stable connection. That's all I use for station jumpers, test cables, and duplexer harnesses.
The old Amphenol PL-259 is the only one to use. I've had mixed luck soldering PL-259's in the past, as I have used mainly the cheap silver plated Teflon ones that can be found at every hamfest. That is until I took some measuring tools to them. I found on the samples of the cheaper PL-259's that where in my junk box, the diameter of the area of the connector that you solder the braid to, was as much as, 0.050" bigger in diameter than the Amphenol brand. With that much extra room to fill with solder and the much poorer heat transfer to the braid because of the sloppy fit, its no wonder that people have had a hard time with PL-259's. I now only use the Amphenol brand PL-259's as I have no time to waste checking to see if they are of the "right" size. As for the bakelite insulation, if you heat it enough to damage it, the PVC in the coax must be in flames by then.
I have installed hundreds of PL-259's and find it much easier to solder the braid to the body if you tin the braid before screwing on the body. This is also the recommended installation procedure by Amphenol which is the manufacturer I use. You can easily do this with a temp of abt 650° and completely tin the braid all the way around. Then use a file to clean up the rough edges so the body will fit. Just make sure to clean all filings that may get between the center condutor and the braid on the end of the dielectric. Then use a temp between 750° and 800° and you'll find the soldering process goes much quicker and smoother. I use a weller EC 1002 variable temp station with an EC 1503 iron. While a bit expensive, the temp controlled stations work well at maintaining tip temperature when soldering the braid to the body. The standard 80W soldering iron will work well with this method as well. As a marine electronics tech, I have replaced many many improperly installed PL-259's. It's a rarity to find one properly installed. Take the time to do it right!
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