RG316 mobile use

[SirJ]

I would rather use LMR400 if I could but that would be odd coming off a scanner.

so I’m installing a scanner in the mobile, to cut down on limited options with hiding RG58 behind panels and edges In between dash pieces I decided a simple rg316 pigtail roughly 4 feet long attached with a so239 Barrel, attached to a short run of rg58 to a Nmo mount, shouldn’t be too much loss correct?

I will be receiving/monitoring VHF low “40” mhz and some stuff up in the 700s and 800mhz range.

 

[prcguy]

You will have about 1dB additional loss at 800MHz in a 4ft run of RG-316.

 

[mmckenna]

Running LMR400 in a mobile installation would be a royal pain in the arse.

RG-58 all the way would be just fine. No need to change cable or add connectors.
But if you wanted to, 1dB isn't going to matter much.

 

[jcop225]

For a Short run like a mobile installation I would not be too concerned. If you want to squeeze the most performance out of it go with LMR-100. Slightly larger than RG-316 and slightly lower loss, especially at higher frequencies.

Rule of thumb is you take a ~0.05dB hit for every connector so if the entire run is short enough you would be better off with small cable the entire way.

Also I'd use a SMA, BNC, TNC, etc. the performance of UHF connectors tapers off above 300 MHz.