Signal loss via connection

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tss1355

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A couple questions on my scanner setup: I have a copper j-pole tuned to 160-162 Mhz that I use to listen to railroad and marine traffic. Right now, I have the following cable run to get to the antenna:

Antenna
25 feet RG213/U with PL259 male at antenna end and BNC male at scanner end
6 inches RG316 BNC female to BNC Male (stress relief pigtail at scanner)
Scanner

1. I am going to move the antenna to a higher location. Can I get by with keeping my current RG213/U cable and using a connector like this (UHF Female to UHF Female Adapter) to add another 25 feet, or will the signal loss be too great? Should I start from scratch and get a solid, un-spliced 50 foot cable?

2. Is the RG316 suitable for the pigtail, or am I losing to much signal to make it worth it?

Thanks for your input!
 

mmckenna

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Short answer: Go for it, it's not going to be an issue.

Longer answer,

RG-213 has about 0.69db loss per 25 feet at 161 MHz. That's hardly anything and virtually unnoticeable.
Doubling that to 50 feet gives you about 1.37dB of loss, still pretty reasonable.
With the 50 feet, you're still going to get 73% of your signal down the cable to your radio. With only 25 feet, 85% was making it your radio.

So, no, I wouldn't be worried about that little bit of extra loss, unless you were doing some serious weak signal stuff.

Sure, in an ideal world, we'd have continuous lengths of cable, using higher grade stuff. Reality is that this is a hobby for you, so we do the best we can with the budget we have. Chasing fractions of a decibel around is kind of pointless unless you are really on the fringes of coverage. Usually small values like this are difficult for the average user to hear.


As for the extra connectors, if you use a high quality connector, you'll see -maybe- 0.1 or 0.2dB of additional loss. I'd challenge anyone to notice that without using some high end test gear.

The connector will be fine. What will be much more important is making sure that everything is properly weather sealed. What will make a bigger difference in your performance is getting your cable wet. This will destroy the cable and connectors pretty quick. Even moisture in the air can condense inside the connectors and cause issues, so it's not just rain you need to be concerned about.

The RG-316 is fine. 6 inches of that will add a negligible amount of loss to your system. The benefit you get from it far outweighs the minor amount of loss it is adding.



1. I am going to move the antenna to a higher location. Can I get by with keeping my current RG213/U cable and using a connector like this (UHF Female to UHF Female Adapter) to add another 25 feet, or will the signal loss be too great? Should I start from scratch and get a solid, un-spliced 50 foot cable?

2. Is the RG316 suitable for the pigtail, or am I losing to much signal to make it worth it?

Thanks for your input!
 
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