New Ham: Which cable for a Slim Jim Ham Radio Antenna?

Newly Licensed Ham Radio Customer asks:

Need some help in buying the correct coax for my Ham radio.
I have just purchase a radio and know virtually nothing about Ham Radios short of getting my tech license. Please tell me what you would consider the best cable to buy?

I have a cheap Slim Jim antenna, running about 50 feet to a Kenwood TS-2000

Two cables come to mind, either of which would be a good choice for your TS-2000 and Slim Jim:

JEFA Tech Low Loss 240 FLEX / RG-8X with UHF Male (PL-259 Connectors)

JEFA Tech Low Loss 400 with UHF Male (PL-259 Connectors)

I'd also recommend the COAX-SEAL sealing tape if your Slim Jim will be outside in the weather.  I know some people put them in their attic in which case you wouldn't need COAX-SEAL.

JEFA Tech Low Loss 240 FLEX is about 1/4" diameter which is close to the size of your standard TV coax for reference.  It is very flexible due to its size and it having a stranded center conductor.  It has 1.81dB of signal loss over 50ft.

JEFA Tech Low Loss 400 is about twice the diameter at just under 1/2".  It will give you a stronger signal compared to the 240 FLEX.  However, the trade-off is that it is thicker and has a solid center conductor which makes it much stiffer.  It has 0.76dB of signal loss over 50ft.
At 50ft, cost is close enough between the two to not be a big factor.

A Slim Jim is estimated to have about 5dB of GAIN, so you are still at a net plus gain with either of these cable options, which is a good thing.  It means you won't be losing the advantage of your antenna in cable losses.

In summary, either cable option will be fine for you.  If you don't mind the thicker, stiffer 400, go with that because it will perform the best.  Otherwise, go with the convenience of the smaller, flexible 240 FLEX cable.  You won't be disappointed with either choice.

JEFA Tech Low Loss 240 FLEX:
http://www.jefatech.com/product/CA-240F-C1-C2-L

JEFA Tech Low Loss 400:
http://www.jefatech.com/product/CA-400-C1-C2-L