Antenna advice needed

[ktx21]

Hello all,

I have two different antenna concerns, one ATCS and one voice.

I am trying to find a replacement 900mhz antenna for mobile ATCS monitoring. My main issue is that my vehicle is an aluminum body, so mounting is an issue for most mobile antennas (mag mounts). Right now I have a Wilson Electronics mag mount that I attach to a large baking sheet. While driving it has to stay inside near my back window, and while stopped I can place it outside if I need better reception. Very far from ideal for many, many reasons. I have tested numerous rubber duck style antennas tuned to 900mhz and they are no comparison to my Wilson mag mount. Even if I remove the ground by taking the Wilson off of the baking sheet, it still picks up better than the rubber duck styles. Unfortunately drilling holes and other permanent type modifications are not possible on my vehicle at this time. I would really appreciate any suggestions that you might have on a better antenna and/or setup.

My second concern is regarding a base voice antenna. Unfortunately whatever antenna I install will have to go inside the attic of my one story home. I do pretty well with the handheld inside my home, but I am looking to expand the coverage as far as I can using the attic. I have seen several folks recommend the Traintenna. Would the outdoor Traintenna be a good option for an attic antenna? How does it compare to a Laird FG1563? Other antenna suggestions? I need an omni as I have transmitters in multiple directions.

Thank you!

 

[popnokick]

Regarding the base antenna and going strictly on the published specs for the outdoor Traintenna and the Laird VHF FG1563... they are essentially the same antenna from form, directivity, and gain factors. However, the Traintenna is 57 inches tall while the Laird is 107".... so it may be easier to fit the Traintenna into the attic.

 

[pro92b]

The Traintenna gain is specified as 3dBi while the Laird is 3dBd. These specs are not the same and the Laird gain is nearly 3dB higher than the Traintenna which it should be given it is almost twice the length.

 

[popnokick]

Ah the old classic dBd vs dBi ruse… fell right into it!

 

[Scanning-NWA]

I ordered the Ground Plane Scanner Kit, with Comtelco Mobile Scanner Antenna, from the Scanner Master website (Product Code 01-541990) and put it up in my attic. I am very happy with its attic performance and highly recommend this antenna for you. Although it is NOT designed for VHF Low Band coverage (not a concern of course for the Rail Road Band), it does a great job with tri band coverage of the VHF Hi Band, UHF and 800 MHz bands and is priced right at $79.95. I like the fact that it has four dround plane radials instead of just three. I think it will serve you well.

 

[Scanning-NWA]

KTX21,
Here is a photo of what the Comtelco Mobile Scanner Antenna (with ground plane kit) looks like up in my attic. No space problems here:

 

[wwhitby]

A non-metallic roof and not being able to drill holes makes it more of a challenge. Have you thought about a glass mount 900MHz antenna? Larsen has one in their lineup.

For a base VHF antenna, I've had good luck with this Tram antenna. It works well on railroad frequencies and is less than four feet tall.