Coax Cable:

RG 213                     RG58

Coax Cable does only nee to do two things:

1) To take the received signal from the antenna towards the receiver.
2) To bring the transmitted signal from the transmitter towards the antenna is through a coax cable.
These are the only purposes of the cable.

Most commenly used are RG-58, RG-213, Aircomm, Aircell.
There are bigger types like 3/8 or 7/8 hardline but this will cost and perhaps it is of no use to use these types simply because the lenght between your antenna and tranceiver is short enough to there is hardly any loss!  
You might start thinking about those when you need more then 50 meters.
(At 11 meters I could not see the difference between 3/8 and Aircomm Plus over 30 meters only in my wallet!)

Very lucky we should be, that there are no big misunderstandings about cable. It is as simple as:
 The first highly depends on the money you would like to spent on cabel.
Overall can be said that: the higher the cost the better the loss.

In extension of the second there are  mis-interpertations by some, regarding "the ideal lenght".
As said, you only have to keep one thing in mind, keep it as short as possible.  

WHAT LENGTH ?
 As mentioned the best length is the shortest, in this way the loss due to the cable is the lowest.
There can be one advantege by extending the length of the cable:.
A HALF WAVE coax cable or ANY multiple (1, 1½, 2 wavelength) length of this will show you: "exactly the same input resistance at both ends of cable". In normal words:
You can measure the exact SWR from the antenna with these lengths of coaxcable.

If your antenna is truly 1:1 it doenst matter, each SWR measurment anywhere on the line and you will find 1:1.
Only when your SWR isnt 1:1 but  higher your measurments wil change accoording to length, this is when it can come in handy to keep the line a half wave long (or any multiple).

And there are always SPECIAL CASES:



OPTIMAL LENGTH BETWEEN LINEAR / ANTENNA / TRANCEIVER ??
 There are stories about the length between an amplifier and the antenna/ transceiver. The above goes for this aswell.
Just keep it as short as possible, there is no benifit to make it anything else 
 
CABEL IMPEDANCE, Other figures
The cable has other cahateristics: it has an impedance, power handling capability.
Most commenly used is 50 ohm's cable.  
Sometimes it could bu usefull to have 75 ohms (for stacking).  Another variaty is: 300 ohms, this is what we call open line.
This was/is still in use for simple wire antenna's often multiband antennas.
 

We will stick to the 50ohms, thats what we needed Flexible/ able to lay in corners etc!

The impedance (50 ohms) of the cable is produced by it thickness, the distance between the two conductors and the material between those conductors.
With the knowledge of this you can now make up your own mind, Is it wise to bend coax cable in a tight curve?
No you just might changes the distance between the two conductors!
POWER HANDLING CAPABILTIES:
The thickness of the inner cable is responsible for the powerhandling capabitlies. The thicker the better.
RG58 wich is one of the thinnest cable can handel up to about 300..400 watts .
Any thicker size cable can handle 1 kw easy
( RG 213 about 1800 watts, Aircell 7 about 2,5 KW at 11 meters and Aircom upto 5 KW.)


LOSS: at 27 MHZ with 100 meter lenght
name
RG 58  6,6 dB
RG 213  3,4 dB
AIRCOM plus  1,5 dB
AIRCELL 7  4,6 dB
 
You can calculate easy with these numbers for example with only 20 meter cable using RG-58 we come to
6,6 / 5 =  1,32 dB loss (100 meters RG 58 was 6,6 dB loss we want the loss at 20 meters: 100/20=5   ..... 6,6/5= 1,32dB)

So when we stay below 50 meters Aircom Plus is good enough we only reach a loss of 0,75 dB then. (not included the connectors etc.)


CONNECTORS:
PL 259 is most commenly used type. although this type is not 50 ohms, I know my mind is a bit extra-carefull but I only use N-connectors these are 50 ohms so any loss wich just might exsist with PL 259 connectors is reduced. Honestly I have to say I never noticed any difference on 11 meters between those connectors.
Use only the amout of connectors you need and that is 2 ! 
Onces tested the S.W.R  this will probarbly be the same next time. How nice it is to see those needles going up, but again this is loss ...extra connectors, S.W.R meter etc. 

                                 Aircell                                               Aircomm


ANTENNA TUNERS
Do not use it.
If your antenna is not resonant at the design frequencie and you need an ATU to make sure the SWR stays below the wanted numbers. You have done something wrong!
 
There is only loss in an ATU due to extra connectors, and the inside of the ATU (coil/capacitator)
Most people use the antenna tuner directly after the tranceiver, it is only logical that the SWR does not become better It is NOT an ANTENNA tuner but only a CABLE tuner!
Remeber a dummyload had an SWR of 1:1,1 but was a terrible antenna the same counts for an ATU.
The ATU is the joker in ouwer system.

DONT USE IT!

ONE EXEPTION:
There is only one way that the ATU may be used for what it is ment for.
That is with non- "conventional"  types of cables and antennas. (that 300 ohm line for example).
The case here is that these impedances are way of 50 ohms. 
But neither will be used by 99,9 % of us 11 meter DXers.

PS Taking a look at most antennas, you'll often vind coils in them. You could look at it as an actual "fixed antenna-tuner", but this is ofcourse not what we are speaking about.

RECEIVING  PRE-AMPLIFIERS
The device, wich can improve a received signal.
Works on 12 volts has an input and output connector (commenly PL259)
This for me is an un-know region at the 11 meterband.
In the new setup I will include one of the below marked pre-amps and will put down the results.
 
Ofcourse,i also had once such a device availible from the CB-market, only to find out the noise level was improving with great numbers perhaps when I used bad cable it could have been an improvement.

The mentioned noise level is the quality figure of the pre-amp. At higher amateur frequencies these devices do come in handy because they do make up for all the loss in cable connectors etc. (I can notice a big difference on 144 mhz and 934 mhz)

Profesional pre-amplifiers like those from MIRAGE or ICE have a noise figure of < 1dB and a gain variable upto 20 dB.
                   
                                                                           pre-amp mirage
The amout of power they can handle is not that high, ofcourse with remote swiches this is a problem you can overcome.

There is only one reason why you should use a pre-amp
To make up for the loss produced by connectors and cables.
So often it is put where it should not be ....at the transceiver his location, this could help in the old-days due to bad receivers but these days the tranceivers all are perfekt and really do not need one.
The right location is at the bottum of the antenna, only then it might bring stations a bit clearer.
Yes almost forgot: The signal wich your antenna does not pick up, can not be amplified by a pre-amp..

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