Which coax for external antenna?

[dmg1969]

I currently have an attic mounted antenna and use RG-58, which is the bottom of the barrel...I know. If I put up an external antenna, I was looking into something like LMR-100, 200 or 240. Or would RG6 or RG8 be OK? I am looking to buy from Show Me Cables. I have bought from the before and were satisfied. They do make custom cables in case I decided to have them install the connectors rather than invest in the tools myself.

 

[rivardj]

Here is a link to a Wikipedia article that contains a table that lists the specifications of various coaxial cables. The cable type is in the left-hand column and the loss in db per 100 feet is in the extreme right-hand column. You will want to select the cable type with the lowest db per 100 feet loss number that you can afford. For every 3 db in loss the signal in the cable is decreased by 50%, something to consider. At a loss of 3 db the signal is halved, at 6 db the signal is one quarter.

 

[mciupa]

Satellite TV coax is dirt cheap nowadays and durable for outdoor use especially for long runs.

 

[popnokick]

Dave- A couple of things to consider in your situation:
1st, the antenna. If you're thinking of the highly-regarded Antennacraft ST-2 it uses a 75 ohm feed (via 300 ohm transformer) and a high quality, low loss quad shield RG6 satellite TV coax is going to be less expensive and easier to install than low loss 50 ohm. In fact, it is sold with 75 ohm cable. You can easily do the connectors on RG6 yourself, and tools to do a professional job on F connectors for RG6 are readily available in any home/hardware store. Not so for 50 ohm cable.
2nd, if you use 75 ohm cable you could easily and inexpensively add a signal amp/splitter if needed. I run one with my attic OCFD for two scanners and it works great with imperceptible signal loss. Of course, I'm in a rural area without heavy RF congestion or intermod interference... as you are too. The ST2 is a very good antenna without the amp, but the good news is that 75 ohm amps are inexpensive to try.... unlike high end multicoupler/amps.
ALSO- Left you a PM here on RR.

 

[dmg1969]

OK, thanks for the input! I replied to your PM. Still thinking about which directions I'm going to go. Grounding issues will dictate if I opt for the external or another attic mount.