More Questions About Coax

[N6YW]

I have some questions about coax, and this will be part of a detailed discussion roundtable on one of the nets I participate in weekly.

In the shack, does it MATTER what 50 ohm coax you use for interconnecting within the system?
To be more precise, is it best to use only one cable from the same reel, say like RG-213 or whatever your favorite flavor? Does velocity factor even matter on these short runs? Personally, I have several different cables in use, all high quality but a mix of RG-8X and RG-213. I have noticed no problems but it begs the question.
Last, is there a preferred cable type by a certain manufacturer that is considered to be the best for the kind of operating we do? I ask this because I want to see the comments and opinions to use in the discussion.
On these roundtables, we have never discussed coax except for an occasional mention about a project but nothing detailed as it is used in the shack. On the air, I have heard many comments like "You would never catch me using anything but Belden 9913" and stuff like that. Some people don't give it a second thought while others are very strict about these choices.
Thanks,
Billy N6YW

[Steve - K4HX]

In the shack, does it MATTER what 50 ohm coax you use for interconnecting within the system?

Generally, no. If the cables are short, it's insignificant. Even if you use RG-58, the loss in a 10 foot section at 29 MHz is 0.26 dB. At 3.9 MHz, the loss is only 0.08 dB. RG-8X is a better choice for higher power. Here the loss is only 0.16 dB at 29 MHz and only 0.05 dB 3.9 MHz.

To be more precise, is it best to use only one cable from the same reel, say like RG-213 or whatever your favorite flavor? Does velocity factor even matter on these short runs?

Unless you are dealing with a phased array antenna system, velocity factor does not matter at all.

Last, is there a preferred cable type by a certain manufacturer that is considered to be the best for the kind of operating we do?

No. If the cable is required to make sharp bends, you should probably stay away from some foam core types because of center conductor migration. Otherwise, use stuff that can handle the power you plan to run and mate with good connectors properly installed.

[N6YW]

Steve
Thank you and I assume you placed my post here on it's own thread. Thanks again.
This is good for the discussion. With a variety of people and perceptions on given topics, it's good to have some material to use in steering a discussion on air, plus it's good for me to have some additional understanding from others with useful experience and knowledge. Books are great, I have lots of them but personal examples from operators are better.
I appreciate it.
73 de Billy N6YW

[Pete, WA2CWA]

I have short run coax cables (RG58U, 58AU, 58BU, 58CU, numerous lengths of RG8U looking type cables but have no clue really what they are) in my shack and workbench that are probably 50 or more years old. So old, even the printing on the cable is wore off. Unless you're dealing at microwave frequencies where length and age could be important odd-ball 50 ohm stuff won't really hurt you. Of course, having good solid and soldered coaxial connector ends is probably equally as important as the coax itself.