Hello and Base Station Setup

[Guest dennisgibson]

Hi all. I've been messing with GMRS since last summer and have been having fun with it. I've put Midland Micromobiles in mine and my wife's cars which we use to talk when running around town and have been happy with them.

 

Last week I decided to order another one to set up as a base station using a power adapter. I put the included antenna on top of our TV antenna mast which is about 25 feet high. It puts the antenna above our roofline. The radio is connected with about a 40 ft. run of RG8X. We tested it out this past weekend and are getting 7 to 8 miles along the I-40 "corridor" that runs between the two major ridgelines in the area which seems pretty good to me but I really don't have a frame of reference.We're in the mountains of Western North Carolina at around 2300' and the tops of the ridges are at about 2500'.

 

I've looked at a TRAM base station antenna so at some point will upgrade to that but am I realistically looking at a significant improvement given us being in mountainous terrain?

 

Dennis

WQVQ594

 

 

 

[Logan5]

you could use better feedline. and I would get that antenna at least 20' higher than your UHF TV antenna, Higher watts could damage your TV tuner.

[PastorGary]

Hello Dennis - Thanks for stopping by.

 

We have found over the years by trial and error that RG8X may be OK for "CB" but the losses and the lack of broad frequency response makes it less than desirable for UHF.  When you are starting with 5 watts, as advertised, getting as much power to the antenna as you can will give you much better results.  The antennas that comes with the units are designed for mobile use where they sit on a car roof or trunk.  That metal car surface gives the antenna something to radiate against and keeps the signal going horizontal.    With no "ground plane" surface, the antenna will most likely interact with the mast and the TV antenna eating more power in the process.  If you must use the antenna that the 'base' radio came with, construct  a 24 gauge sheet steel circle 24 inches in diameter and L-Bracket it to the mast.  Replace the RG8X with something like RG213 (for now) and stick the antenna to the top center of the sheet steel.  That will give a ground plane surface and the better cable will get more power to the antenna.  That should increase your range to 10 or 12 miles or so under AVERAGE conditions, depending on terrain (as you mentioned.)  If this is just for keeping track of family members while on near-by errands, etc., this should work out OK.   In the future, you could go with commercial gain type base and mobile antennas to extend the range even more. 

 

Good luck with things and please consider registering at our main website and then here at the forum.

 

https://www.mygmrs.com/

 

 

 

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[Guest dennisgibson]

Thanks Logan5 and Gary, and here I thought I was master of the airwaves. I wondered about the distance from the TV antenna and the use of a ground plane. I had seen the "pie plate" antennas online but couldn't tell if they were some sort of specialized application. Looks like I have another weekend project ahead as soon as I can get some better feedline and a new antenna.

 

I've been registered on the main site for awhile now. The repeater directory is a great reference. I'll register here in the forum as well. (I confess I've lurked for a long time here too.)

[dennisgibson]

Haha...think I have my regular forum account set up. The RG213 is in the garage and now waiting for the new antenna to arrive. I'll move this project over to the regular sections when I start the install and see what can of performance changes I can get.

Dennis

WQVQ594

[coryb27]

Keep us posted!

[WQYC236]

A big garbage can lid is not a bad make shift ground plane for a mobile mag mount. If you get lucky it will be close to a multiple or fraction of the wave length:).