chain plate studs and bolts; coax cable

[crieders]

2 distinct questions:
1. i want to re bed the chain plates and re bed the studs (bolts) and nuts. What are the sizes and whats a good place to buy them?
2. Cable in the mast to be replaced. Is southwire RG 8x mini the right product or R 59. I am told that the resistance in ohms is wrong for the R59
Thanks very much

[Stu Jackson]

1. i want to re bed the chain plates and re bed the studs (bolts) and nuts. What are the sizes and whats a good place to buy them?
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Loosen one turnbuckle, remove the cover plate and remove one of the two bolts, washers and nuts, trundle down to your local hardware store (if it's a good one it'll have stainless steel fasteners, most stores do) and buy a dozen each.

In reality, I've rebed all of my chainplates over the years and never felt the need to replace those.

[mdidomenico]

i did this last summer.  fortunately my mast was down so the task was easy.  i get all my hardware from boltdepot.com.  i removed my chainplates entirely to rebed the slot with epoxy.  if you're not going to do this, i agree with Stu probably no reason to replace the bolts.

[Dave Spencer]

Cliff,
R59 is definitely not the right  coaxial cable for your antenna. RG8x (not sure about "mini") would do the job but the run is quite long and the loss will be significant. Last year, I replaced my coax with RG213 which is excellent but has a large OD making running it more difficult than a skinnier cable. However, the losses are insignificant compared to RG8x. LMR400 is supposed to be the best but as I dug into the specs, it looked like its water resistance was not as good as the RG213. (I found that tidbit on the Internet so it must be true!:D)
Here's a good technical overview on coaxial cable by Steve D'Antonio.

https://www.passagemaker.com/technical/the-skinny-on-coaxial-cables-connectors

Like everything, there's no free lunch. Smaller cables have higher losses and bigger cables have lower losses.  In addition to the article above, there's lots of data on the Internet comparing different cables and the losses associated with each.   

[Jon W]

For coax/antenna cable length, the guidelines I was given are under 50 foot length use RG8X, for 50 foot and greater use RG213.

[Ron Hill]

Cliff : What you want in all VHF marine cable and connectors/plugs are 50 ohm! 

TV stuff is 75 or higher ohm resistance impedance - so don't use it or you will have a mismatch ! 

A thought

[KWKloeber]

Cliff

Dunno if the below helps or hurts but this was the answer when I asked a professional in the field of RF and cabling (who also happens to be a Catalina owner.) 

[Edited] - Cliff, LMR-240 coax is 50-ohm impedance (not resistance) which is what you want for marine VHF (155 - 175 MHz frequency) (it doesn't need to be exactly 50, 48-51 is fine -- the 50 "standard" was selected long ago as a compromise.)

https://www.timesmicrowave.com/DataSheets/CableProducts/LMR-240.pdf

Max signal loss (attenuation) for different coax is listed here:
https://en.wikipedia.org/wiki/Coaxial_cable

- Ken


Ken:
Times Microwave Systems' LMR-240   
It has the same outer diameter of RG-8X Mini, yet offers improved loss characteristics as well as all the other benefits of LMR cable. Same loss as RG-213/U" 

Or for even more flexibility, use LMR-240 Ultraflex.

Don't forget the UG176 reducers so it will fit into the usual PL-259 connectors: 
http://www.texastowers.com/ug176.htm