Railfan Technology > Reception Problem with Railcom Mobile Gain Antenna

I purchased a mobile gain antenna from Railcom approximately two years ago. On a recent Sunday I was using the antenna and noticed that reception was very faint. I tested the antenna by turning on the National Weather Service radio stations for Cleveland, Ohio, and to my dismay they were not coming in. I disconnected the antenna from my scanner and checked those same frequencies with the rubber antenna that came with the scanner. The weather stations came in loud and clear. It appears that the co-axial cable is either loose, frayed or broken where it comes out of the base of the antenna. When I did a test later of my scanner and the weather frequencies, I noted that reception improved when I pushed the cable toward the antenna base of the mobile gain antenna.  I am not sure how the cable could have become damaged. The week before I used the antenna and it worked just as good as ever. All the antenna did between the two Sunday's was sit in my closet. Any advice or thoughts about how to get this problem fixed? Thanks. 

Buy a new mag mount base or a new base and whip.
While it is possible to replace the coax, it really is difficult to justify when the low cost of replacement is considered. 

http://www.theantennafarm.com/catalog/pctel-maxrad-rgpli-1105.html (other radio outlets also carry this product)

JW
 



Edited 2 time(s). Last edit at 09/06/16 11:18 by ChessieSystem.

Very common problem, the coax cable interface is the quality trick with most antennas but is also very susceptible to wear or damage. It may be as simple as a thread of the braided coax outer sheathing/ground has moved to a situation where it shorts across the antenna connection, causing no signal. Or the actual center conductor could have broken away at the antenna connection, or broken anywhere along the cable. Putting an ohm meter onto the center conductor will tell you if there is a short to ground, or continuity between the ends of the cable, but not much else.

You really need to visually check whatever method the manufacturer used to transition from the center conductor to the antenna mount. Sometimes they have a separate metal fitting and sometimes they just solder to the center pin of the antenna base. But sometimes it's not the transition to the antenna base but the connector on the radio end of the cable. Same situation, visually inspection is best but eventually you have to tug on something or reflow the solder or find something to replace. I don't know how your's is built, maybe someone else has the details.

Good troubleshooting by the way. Yes, it's easily an intermittent condition as well, depending on how it's designed. That's the part that you pay the bucks for.

+ Agree, it may not be worth the cost or time, a new antenna may be the simplest way to go.



Edited 1 time(s). Last edit at 09/06/16 11:15 by TCnR.

I've had a number of mag mount antenna bases that failed over the years, mostly due to a broken center lead wire in the coax. It takes a real beating opening and closing the door on the coax. I've found (as others suggested above) it's just easier to replace the whole thing. I have an older vehicle so I just drilled holes and mounted antenna bases in the roof. It's far more durable and I even found hole mount NMO antenna bases with a BNC connector available for less than $20 on Amazon.com.

Good luck!

James Nelson
Thornton, CO
www.flickr.com/mojaveflyer