Batboard

Ok. I got my GMRS license in 'processing'.

Have 3 Motorola GP350 handheld radios (4 watt) each.

I have a Tram 1170 4.5DB gain antenna for the car coming in with magnetic mount.. BNC connector adapter..

I want to put up a semi-base antenna for testing here at the house and figured a fender mount NMO base with BNC on the other end would work and just bolt it to a window sill..



I am debating on the MaxRad 3 DB gain (no ground plane) for $40.. or the Tram 1175 with 2.4 DB gain (no ground plane) for $30.

or the Browning BR-450 5.5 DB gain (ground plane type) for $27 or Tram 1177 5 DB gain (ground plane type) for $19.

If I went with the 'ground plane' type how could I ground this?? can I just run a 12 or 10 AWG wire to the 'ground' part of an household outlet??

Or should I buy a NMO mount with the ground plane 'radials' coming off like this Tram 1465 kit, does the radials make it grounded??



Needless to say I'm confused on the 'ground plane' issue..

Electrical ground is not the same as RF ground. Most mobile antennas need a ground plane which is ideally the rectangular roof of a vehicle underneath it. Those radials serve the same purpose when not used on a vehicle. The no ground required antennas would work better on a window sill as is but they too would benefit from a ground plane beneath them.

Most 1/2 wave anennas are ground plane independent and do not require a ground plane.
All other types do require the use of a counterpoise, to act as the second half of the main radiating element.
gain is simply the design of the antenna to place an effective amount of your signal closer to the ground, gaining you some added range in mobile coverage.
This works well in open locations such as low urban sprawl, unlike urban locations where many repeaters are located, in this venue, a 1/4 wave would serve you better, as the radiated signal is propagated effectively upward, unlike a gain type that compresses the signal towards the horizon, minimizing the overhead coverage afforded by a quarter wave antenna.
Think of a doughnut, that is what a quarter wave antenna's signal appears like if you coud see it, then think of a flattened doughnut, and this is a reseblance of what a gain antenna's signal appears like....The flattened signal is the added 'gain' of the energy being radiated outward, towards the horizon.

Well put, AEC.

Most two way antennas have a radiator AND a counterpoise. A mobile antenna has the car body for the counterpoise.

Counterpoise is usually a 1/4 wave in diameter and is often said to be the ground plane.

Thanks folks..

Went with the Tram 1465 Ground Plane mount.. going to put antenna on top of roof attached to chimney.. only 5 feet from the bedroom window.. went with LMR240 coax with PL259 and BNC already installed.. I ordered a 12 foot length to come in thru the window for testing..

I also ordered the Browning BR-450 antenna (5.5db) for this testing/install.. just want to see how far I can get with it.. using in conjunction with Tram 1170 mobile antenna for the car (4.5db)..

Anythings got to better than the 6" Motorola factory antennas on the GP350's I have.. especially when I am sitting in the car..

In other news my GMRS license got approved and I got my call sign..