LDF5-50 !
You did say, "the best". Actually, you could go up to LDF8-50, but if you're using it for your car whip antenna... it might be a bit hard to run through the firewall.
Ok... seriously though. It really depends on how long the run is.
RG58 is first choice. It's cheap, it's thin (about pencil thickness) and it's easy to run. This is the standard cable that is used for cars.
The coax isn't known for being high performance, but this is a tradeoff for it being cheap and flexible.
For 27MHz it really doesn't perform all that bad, and you're only running <15W PEP.
A word of note on RG58. Even though RG58 is a standard, very few cables sold meet the standard. Sad to say that the coax that Jaycar and Dick Smith sell that is not already pre-fabircated is poor quality coax.
If you are in any doubt, when you strip the coax, there should be a thick copper braid that is hard to part. If you find a braid which is only a few thin wires or the wires fall apart or their is aluminium foil for shielding, then it is poor quality cable.
RG213, RG214, RG-8, LMR400 is all very similar.
It's about as thick as your finger. It's still realatively flexible. It does however perform much better than RG58.
This is that standard cable that most people use for a 27MHz base station and ham radio operators use for HF.
This cable also has an acceptable performance on UHF CB.
Belden 9914 is very similar to the RG213 type cables, but it is much less flexible. The cable is rather stiff, but it does have a much better performance. It is realitively expensive and connectors can be hard to find. It was a favourite with UHF CBers during the late 80's.
LDF1-50, FSJ1-50, RFS14-50 Andrew "Heliax" or RFS rigid cables are the best cables.
They are not as expensive as some people might think and are often cheaper than retail price for the other cables above.
$3 per metre for the cheapest up to $50 per metre for the most expensive. If you have enough people, buying a bulk roll of cable is quite cheap. The connectors can be as cheap as $10 each, but most are about $20-30. For the larger high performance cables, they can be as expensive as $200 each.
There is however a very large surplus market of heliax style cables and they can often be found at scrap metal dealers where you can buy them with the connectors and all for their weight in copper price. If the spot price of copper is $8 per kilo and the cable weighs 5kg, then you can expect to pay ~$50 for it. Any more and the scrappy will get less for it if he melts it down, because most of the weight is PVC and foam which produce nasty toxic fumes when he melts them down.
LDF1 cable is about as thick as RG58, LDF2 about as thick as RG213, LDF4 is about as thick as garden hose.
LDF8 is like sewerage pipe thickness.
LDF1 is easy to bend. LDF2 also relatively easy, LDF4 has a limited bending radius. Kinking rigid cables will serverly effect their performance. You have no chance of bending LDF8 once it comes of the back of the semi-trailer.
RFS/LCF/HCF cables are made by RFS industries. They are often cheaper than Andrew heliax, and their connectors are very easy to terminate. No soldering required and they can be assembled in minutes.
FSJ cables are made by Andrew. They're much more flexible than LDF cables.
Examples of these higher quality cables are...
LDF2-50, LDF4-50, LDF5-50
FSJ2-50, FSJ4-50
RFS12-50, LCF12-50, LCF34-50, HCF34-50, LCF78-50
Heliax cables and the like will perform well right up to and sometimes above 15GHz.
For 27MHz HF CB, they're overkill, but you can take comfort in their performance.
