Railfan Technology > Base antenna question

I know there are a ton of threads about antennas, but I have done a search here for this answer but cannot find it (I do remember prior threads about mobile antennas, got great insight). I am looking to get the traintenna vertical outdoor base antenna. Where I am confused is it says it comes with a 12" RG8X cable with a female N connector. Looking at coax cables they have RG8X cable at different lengths, and basically the shorter the cable the better. But I need the 40' cable since the antenna will be at the roofline of a 2 story house, and I have to run it to my scanner on the first floor. Also I have to choose connectors.

So, my convoluted questions are: is the 40' coax a bad thing and if so what should I get, and it appears I would need an N male to connect to the antenna, and a BNC male as to hook to the scanner - sound right? Also, it says the N connectors are more water resistant, but will it still need to be taped up or will the connection be water-proof enough?

RG8 cable might work OK, but LMR400 cable will likely work better. LMR400 cable is what commercial radio installers use for long cable runs--there is much less signal loss in the cable. LMR400 cable is cumbersome--stiff, about the same diameter as your index finger, and not very cheap, but it does the job. I use it where I work and on my base radio at home. I would also look for a commercial base antenna tuned to the 161 mHz frequency. There are numerous makes and models out there. I generally don't trade with the outfits that market specifically to the railfan market--their products are often overpriced and frequently not the best quality. And, of course, a great antenna setup won't work well if it is attached to a radio that has poor selectivity and sensitivity specs--a common deficiency in many scanner radios. Waterproofing is very important. Any cable connector, including N connectors, that are exposed to the elements should be waterproofed. The best setup is to put Mastik on the connector of the antenna to the cable, and to, if possible, have no other cable connectors on the exterior of the structure. N to BNC adapters are available, but there will be a slight signal loss in the adapter--unavoidable if that is the connector on the back of the radio. BNC connectors are handy, but they are not my favorite for making a solid antenna connection.

To illustrate the difference quality can make, from my home base station (a 50 watt commercial radio base station connected with LMR400 cable to a commercial base antenna), I can receive and open a mountaintop repeater 45 miles away and not direct line of sight--there is a high ridge between the repeater and me.

Oh, one last thing, make sure that base antenna is well grounded. Mine is grounded with bare copper cable tied to a 6' ground rod driven all the way into the ground.



Edited 4 time(s). Last edit at 10/31/17 13:07 by WW.

There's a simple method in constructing your own ground plane antenna using a panel mount female SO 239 connector, & #12 copper wire. The following ham radio website gives details on how to construct the antenna.

http://www.hamuniverse.com/2metergp.html

If you are unable to construct your own antenna, contact your local Ham Radio Club and they will be happy to assist you in constructing an antenna for you.



Edited 1 time(s). Last edit at 10/31/17 21:35 by okikuma.

Another type of antenna that one can use with their scanner is the J-Pole antenna. A higher gain antenna with low noise ratio. The best part is the antenna doesn't need to be mounted up high. It can be mounted lower to the ground with good results.

Here's a website whereas one gentleman builds the antenna to order.

https://www.jpole-antenna.com/shop/railroad-band-noaa-weather-160-162-mhz-j-pole-antenna/

The antennas are easy to build. I've built several over the years for amateur radio operations. It is all based on 1/2 inch copper pipe and soldered together.

Here's a website with formulas to build your own copper pipe J-Pole antenna.

http://www.kn9b.us/j-pole

With any type of antenna that is mounted, one must make sure there is proper grounding for lightning protection.



Edited 1 time(s). Last edit at 11/01/17 13:42 by okikuma.

If you are not comfortable with installing the connectors you can order cables with an "N" connector on one end and a "BNC" on the other end. It's a bit pricy but you're only going to purchase it one time.

As for an antenna recommendation, the Cushcraft "Ringo Ranger" is a decent product. There are three models that cover the 161 MHz band and they have different gain factors. I had one at my home for about 15 years. A storm brought it down and bent a part. I straightened that out and the thing still worked great. It's made for the Ham Radio world but it will tune to 161 MHz.

John

Thanks for the responses.

RG8 is not great at VHF. As stated LMR400 is better but hard to work with. An other option is RG 9913. It looks and feels like RG8, but has much lower loss at VHF and UFH frequencies. It is used a lot by HAMs for these frequencies.

Scott,
AB6YS

Scott Schifer
Torrance, CA
TinyTrains Website

If there is room, one can mount their antenna inside the attic away from electrical power lines, and have very good reception.

Cole42,

What was your final decision on your antenna selection?