best coax for scanning...

[car2back]

I am about to begin a project installing new anntenas in my car for my 2 scanners (an 800mhz and a VHF High band 5/8 whip)....

I am wondering: Can somebody explain the different kinds of coax available and suggest best coax cable to use for both the 800mhz and the 148-177mhz bands? I have a roll of R/G 58, but am not too sure if it is the best option.

thanks!

 

[Tweekerbob]

you should be AOK as long as you keep the coax lengths to a minimum (don't coil up the excess in the trunk and call it good). Also, avoid all adapters if possible or keep their use to an absolute minimum as well

 

[car2back]

How long is too long? Is 12' to 15' ok?

I am planning on using NMO mounts that use a BNC terminal on the scanner side so I can avoid connectors/adapters all together

thanks

 

[W4KRR]

How long is too long? Is 12' to 15' ok?

I am planning on using NMO mounts that use a BNC terminal on the scanner side so I can avoid connectors/adapters all together

thanks

12 to 15 feet of RG-58 should be okay for most mobile installations.

They do make some lower loss cable for mobile use, so called teflon cable, which has a white outer jacket and is slightly larger than RG-58, but I don't know any other details, or if it is worth it for a mobile scanner installation.

 

[Tweekerbob]

How long is too long? Is 12' to 15' ok?

I am planning on using NMO mounts that use a BNC terminal on the scanner side so I can avoid connectors/adapters all together

thanks

That'll do fine! That length won't give you any practical loss at vhf and just a small amount @ 800. Do like the pros do and get yourself an 800 antenna with around 3-5 db gain and you should be golden.

 

[Al42]

15 feet of RG58 gives you just under 2db (1.99db) loss at 860 MHz, so that's acceptable. As Bob said, an antenna with a little gain will counteract this completely. At 150 MHz, the same cable gives you a loss of 0.7db, so I wouldn't worry about it.

Your only other choice is lower loss cable - LMR400 gives you 0.57db loss at 860, but costs a lot more, is a lot thicker (harder to hide in a car) and a lot stiffer (harder to manupulate).

Commercial 860 MHz installations do fine with RG58. I wouldn't hesitate to use it, as long as it's fresh (cable deteriorates over time).

 

[kb2vxa]

Hi Phil and all,

How far can you go with coax in a mobile? RG-58 is just fine and don't mind the adapters, they don't mean a thing except to couple dissimilar connectors. Forget about LMR or any large diameter cable, it's a bugger to work with and nearly impossible to hide unless you want people to ask about the snake under the carpet.

No comments from the peanut gallery, I have been doing mobile installations since 1965. (;->)

 

[car2back]

I had a snake under the carpet once... that wasn't fun...


Thanks for the help... hopefully before long I will be posting pictures in the "Installs" thread!

 

[Tweekerbob]

Hmm...I dunno...did they actually have cars in 1965?

 

[N_Jay]

Hmm...I dunno...did they actually have cars in 1965?

Yes, they had cars, but they did NOT have Teflon low loss cable. :lol: :lol:

AND

They did not have 800 MHz :evil:

AND

Most radios were trunk mount, so the only cable you snaked under the carpet was the control cable that was bigger than RG-8. :twisted:

 

[MacombMonitor]

Hmm...I dunno...did they actually have cars in 1965?

Sure did...MUSCLE CARS that would blow the doors off most of the crap made today!