Outdoor antenna for Pro 106/197

woodmedic · #1 (**permalink**) 01-18-2011, 2:14 PM

Hello all! I am about to install a Radio Shack 20-176 antenna on my roof. I currently have a Pro 106 scanner that I would like to connect to this antenna. I have read multiple threads about coax to various scanners. The thing that I cannot find a solid answer on is what type of cable I should use for this scanner. I have seen where many people use RG-6. I would like to do this, however, in my manual, it states to use RG-58. I also understand that RG-58 is 50 ohm and RG-6 is 75 ohm. I would rather use the RG-6 but I want to use which ever one would have the best performance. I am trying to listen to vhf hi stations from approx 45 miles away. Which cable would you gurus recommend for this combination of antenna and scanner. BTW I will later be getting a Pro 197 to leave connected to this outdoor antenna but I understand that they are the same internally as the Pro106. Thank you guys for your time.

korpseofdeath · #2 (**permalink**) 01-18-2011, 3:30 PM

I have that exact same antenna installed on my roof, with a 100' line of RG-6 cable. RG-6 is rated at 75OHMs, I figured it matched up pretty good with the scanners, (somewhere between 50-70 OHMs I believe). I have tried at first the RG-58 cable which says it is 75OHM too, but the performance suffered with it. So I switched back to the RG-6, and the performance was better, so I stuck with that, and returned the RG-58 cable. Just my input for what I ran into. =D

ranger821 · #3 (**permalink**) 01-18-2011, 4:12 PM

NORMALLY the smaller the coax, the more loss you have. RG 58 over about 35-40 feet you are lossing a lot. I use RG 213 or LMR 400. LMR 200 will do fine as well. To some this is over kill, but the OP is trying to hear stuff 45 Miles away. That's a far poke for most antennas unless they are mounted high in the air with good coax. You did not mention your location. That makes a big difference. Here on the Gulf coast the signals travel a long way because it's flat and not a lot of tall buildings to obstruct the signals. My 20-176 is only up about 15 feet and I can hear 40-60 miles out.

woodmedic · #4 (**permalink**) 01-18-2011, 4:37 PM

I live in the panhandle of texas. Here there are zero trees and the terrain is very flat. The RG-58 that I was thinking about trying is rated at 50 ohm which is what the scanner manual calls for. I just can't decide which one to go with.

ranger821 · #5 (**permalink**) 01-18-2011, 5:06 PM

How high are you going with the scanner antenna?? Higher is better. How long is your coax run going to be??

woodmedic · #6 (**permalink**) 01-19-2011, 8:36 AM

It should end up around 25 feet up. I am going to mount it on a pole and fasten it to my chimny. I have a single story house. The cable run is going to be less than 50 ft.

ka3jjz · #7 (**permalink**) 01-19-2011, 8:50 AM

Don't pay attention to the scanner manual re the impedance issues. It's a bunch of baloney. Without getting technical here, the loss between using 50 ohm and 75 ohm cable is not worth mentioning. However RG58 is crap coax at 800. At such a short run, RG6 will do just fine.

best regards..Mike

ranger821 · #8 (**permalink**) 01-19-2011, 8:57 AM

If you have a working fireplace with that chimney, keep the coax as far away from it as you can. Antenna as well.

woodmedic · #9 (**permalink**) 01-19-2011, 9:08 AM

Thank you all for the input. I will try the RG-6 and repost the results. It may be a few days however due to the upcomming weather. My chimny is a large brick covered chimney so the coax wont be close to any heat or metal.

ranger821 · #10 (**permalink**) 01-19-2011, 10:07 AM

Ok. sounds good. I think you will be impressed with the 20-176. sometime in the next month or so when it warms up a little here on the Gulf Coast, I will be getting mine up a lot higher.

W2NJS · #11 (**permalink**) 01-19-2011, 10:21 AM

50 ohm coax provides a better match to what you radio wants. No one has mentioned another type of coax which is cheap, 50 ohms, and the same size as RG59. That coax is called RG-8X and it is less lossy than RG-58 by a wide margin. 8X uses RG59 sleeve adapters if you're using PL259 terminations which also makes it a breeze to construct. The ideal 50-ohm cable is RG-8U but it's heavy and quite expensive.

woodmedic · #12 (**permalink**) 01-19-2011, 12:03 PM

I am going to give the RG6 a shot since it is so easy to get. If it doesnt perform like I want it to, I will hunt down some RG8x. Thank you for the info!

woodmedic · #13 (**permalink**) 01-20-2011, 2:10 PM

I got my antenna installed yesterday despite the crappy weather. The problem I am having now is that although I am able to pick up the Sherrif Dept traffic from about 30 miles away, it is pretty scratchy. Today the same frequency is just barely audible. I cannot pickup the VHF hi bands from the town 45 miles away at all. Again I have the Pro 106 which I understand is prone to overload. My question is would an FM trap possibly help me? There are two fm radio stations within 3 miles of me. One of them is 30000 watts and I don't know what the other is. Would blocking the FM radio frequncies help me pick up VHF hi from further out?

woodmedic · #14 (**permalink**) 01-21-2011, 10:33 AM

Success!! I went ahead and bought the cheap fm trap from Radio Shack and installed it. Instant Gratification! I can now clearly hear the city 45 miles away from me that I was shooting for!! I am very satisfied with the Pro-106/20-176 antenna combination. The FM trap was worth every penny as well! I gained around 20 miles worth of receptions by adding it alone!