Question for weirdjim

[bluerooster]

Is there a reason to not use RG8x to replace RG58 in my Cherokee? I have a run of coax to com 1 antenna with a worn jacket, I have about 100' of rg8x, new. and no rg58.

 

[flyingron]

Weight and the effort of getting the connectors to match. On the VOR/LOC and COM you won't miss much.

 

[Bell206]

Is there a reason to not use RG8x to replace RG58 in my Cherokee?

FWIW: have seen RG8 used in both E/AB and TC'd aircraft. Since RG8/x has a stranded core and is not milspec there tends to be mfg'ring variances that can affect service life and performance. And technically replacing 58 with 8x in a TCd aircraft is an alteration vs a replacement. Regardless, you'll be ahead to install RG58 over RG8x every time in any aircraft.

 

[jesse]

RG-8X is a bit larger in diameter but has a bit less line loss at greater than airplane length differences then RG-58.

At 15 ft and 120 MHz, RG-8X loss will be 0.54dB. Where RG-58 would lose 0.63dB in that scenario. Negligible and not worth worrying about.

What is worth worrying about is bending radius. RG-8X minimum bending radius is 2.5 inches. RG-58 comes in at 1 inch. Those are one-time limit bend radiuses, I’d rather not bend to the limit in airplanes.

The difference in bending radius is primarily because RG-8X has a foam dielectric core. RG-58 has a solid one.

So all things said. I’d say it’d work fine, but I would personally use the RG-58 because of the superior bending radius which is important in aircraft which have less than ideal amounts of room.

I work with different coax types quite a bit in amateur radio. I avoid the hell out of both RG-8X and RG-58 because of loss issues at greater distances (not a factor in airplanes). RG-8U is a bit better. I prefer LMR-400 for VHF work if cable distances start pushing north of 50 ft.

 

[bluerooster]

As to the bend radius. There is no need for a tight bend in my situation. Feedline loss being negligible I'm not worried about that. so I'll use what I have. Size is not that much different, and I have BNC to fit rg8x on hand.

So, your a ham? Do you work HF? The only VHF I do is in the airplane. I hang out on 20, 40, and 80 mostly.

 

[wsuffa]

RG-8X is a bit larger in diameter but has a bit less line loss at greater than airplane length differences then RG-58.

At 15 ft and 120 MHz, RG-8X loss will be 0.54dB. Where RG-58 would lose 0.63dB in that scenario. Negligible and not worth worrying about.

What is worth worrying about is bending radius. RG-8X minimum bending radius is 2.5 inches. RG-58 comes in at 1 inch. Those are one-time limit bend radiuses, I’d rather not bend to the limit in airplanes.

The difference in bending radius is primarily because RG-8X has a foam dielectric core. RG-58 has a solid one.

So all things said. I’d say it’d work fine, but I would personally use the RG-58 because of the superior bending radius which is important in aircraft which have less than ideal amounts of room.

I work with different coax types quite a bit in amateur radio. I avoid the hell out of both RG-8X and RG-58 because of loss issues at greater distances (not a factor in airplanes). RG-8U is a bit better. I prefer LMR-400 for VHF work if cable distances start pushing north of 50 ft.

Agree, and note that the shielding coverage on the LMR series tends to be better than the RG series.

I'll use LMR-240 for shorter distances and in the mobile environment and LMR-400 for longer VHF runs and High power HF runs. Up on the mountain 240 is fine (short cables and plenty do line-of-sight), but at home it's almost all -400.