Omni Directional Fixed Station Antennas For ARMER

[JASII]

I am just curious what type of experience people here have had with fixed station omno directional antennas on the ARMER system. I still have a discone on my home, but it is only using 9913 and nearly a 100 foot run. It is maybe 35 feet above the ground. I hear my local sub-system just fine, but I am curious how many counties away people here have heard ARMER sub-systems? Since feedline is so lossy at 800 mHz I am wondering if I am actually resulting in net loss with just 9913 cable. I know that there are formulas to figure this out, so if anybody has any URLs to figure this out, feel free to pass them along. I am also giving some thought to just getting a gain type mobile antenna and putting it on a magnetic mount and keeping it near the BCD996T. If anybody has tried this on ARMER, how well does it work out? I also understand that since 800 mHz is so lossy that there are actually mobile antenna mounts with very low loss cable for the short run of cable from the mount to the radio.

 

[dwgelle]

I have a 13 element 800 mhz beam that I can pull in from about 40 miles away with RG 59. But 9913 is pretty good coax for a scanner. But like anything, antenna height makes all the difference and depending what you want to listen to. If you can get a tuned antenna around 800mhz it will make a lot of difference too.

 

[smokeyjones666]

Well, according to the coax calculator at Coax Calculator, 100' of...
Belden 9913 = -4.081dB
Times LMR-400 = -3.771dB
...@ 852.36250 MHz (The control channel of Hennepin East.)

The next size up would be Times LMR-600 with -2.43dB for 100' at that frequency, but it seems to me that the result wouldn't be worth the effort of upgrading to the larger cable unless you were combining it with a major increase in antenna height and had to replace the cable anyway.

According to the calculator, you're doing much better than I am with my combination of RG-6 and RG-11 @ 100' (Not that I know exactly how many feet I have installed. If I were to guess, I've probably got roughly 60' of RG-11 (-2.795dB) plus another 70' of RG-6 (-6.322dB). Add in four barrel connectors, a balun, a FM broadcast band filter and a F to BNC adapter (Let's say -2dB, just guessing.), bringing me to a grand total of -11.117dB before we get to my radio. In Ramsey county, a couple of miles from Hennepin with my Antennacraft ST-2, I can pick up Ramsey (203), Hennepin east (201), City Center simulcast (101) and Minneapolis N/S simulcast (109) with ease. I struggle with Hennepin west (202) and can barely decode any traffic on a good night. So I can get one county away, but it's a close county and it's huge and I can't quite reach the other side of it. I haven't tried Washington, Dakota or Anoka counties yet.

I don't think your feedline is holding you back, but I'm thinking that dwgelle's example with the 800MHz beam may be the one to follow if you want to get some real range. The only disadvantage I can see to that is without an antenna rotator, you're going to have to decide ahead of time which system you want to monitor and point it in that direction from the start.