• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

Coax Cable

Status
Not open for further replies.
Joined
Mar 19, 2008
Messages
14
#1
What is the best cable you can get for an outdoor antenna, the antenna base is about 6 feet away from the scanner. I've looked around and it seems like a lot of people like LMR400, what about LMR 600? Thanks for the help
 
Joined
Apr 20, 2004
Messages
2,479
Location
Newport, Tennessee
#2
At 6 feet, it won't matter to much about the coax.
LMR 400 is good for higher freqs because of it's low loss factors, but at 6 feet pretty much any 50 ohm cable will do.
Coax loss is rated at 100 feet lengths.
Example: (in theory of coarse)(also depends on the frequency the loss is calculated for)
coax loss at 100 feet = 6db
at 50 feet it would be 3db
at 25 feet it would be 1.5db
at 12 feet it would be 0.75 db
at 6 feet it would be 0.375db
see what I mean?
 
Last edited:
Joined
Feb 6, 2007
Messages
5,907
Location
175 DME, HEC 358° Radial
#5
kb2vxa said:
Danny, your math is a bit off. The decibel scale is logarithmic, not linear.
No, his math is correct. The db scale is logarithmic in terms of power ratios. But a 6 db cable cut in half would have 3 db loss per each half.

Here. Go play with this:

http://www.ocarc.ca/coax.htm

For convenience sake, use LMR400, at 2004.5 MHz. It works out to be 6 db loss for 100 feet. See for yourself.
 
Joined
Jul 13, 2007
Messages
131
Location
Olive Branch, MS
#6
I just use mini 8 for my short runs, since it is usually better shielded than RG-58. It is just slightly larger, only a few cents more a foot and is just as flexible.
 
Status
Not open for further replies.
Top