Setting up the TRAM 1486 for GMRS use.
The Tram 1486 is a high-performance UHF fiberglass Base Antenna with a 200-watt power rating. This single section antenna is 5’3″ tall and is rated for 135mph maximum winds. Great for GMRS, Amateur, or Commercial use!
- UHF fiberglass base antenna
- 5’3″ (1.6m) tall
- Single section
- 5/8 wave 3 elements
- 7″ (19.5cm) radial length
- 10MHz bandwidth
- 6.5 dBd gain
- Radiator and coil are hermetically sealed in fiberglass tubing for low SWR in all weather
- DC ground construction allows static dissipation for low noise ratio and maximum lightning protection
- Mast diameter accepted is 1 3/16″ to 2 7/16″ (30-62mm)
- UHF (SO-239) connector
- Max power 200 watts
- 50 ohms
- Maximum wind 135mph (60 m/sec)
- Includes cutting chart
This is the first antenna that I have purchased that required cutting it to match the frequency. I have always built single band antenna, whether it be dipoles or verticals. Now this TRAM is some type of multi-section vertical. I hope i do not screw up the trimming procedure. The last thing I need is a new antenna that can not be used on any band HAM or GMRS.
I did assemble the antenna and put it up on my 10 foot mast in the back yard. This was to allow me to see how it operated and check SWR on it prior to cutting. The only two bands that I care about is the Ham 440 and the GMRS 462/467 MHZ. The SWR was 3.6 on 440 and even worse on 462/467. So it was taken down and brought into the garage. The first step was to remove the outer fiberglass pole from the assembly. That is done by locating the the set screw at the base of the antenna. The package comes with 2 allen wrenches. I loosen the screw and slowly pulled it off.
The single sheet instructions that come with it absolutely suck. It is just a chart on what frequency you plan on transmitting on with the length of each section should be.
We are going to setup the antenna for 465 MHZ. This way it is right in the middle of 462 and 467 and the bandwidth will be broad enough to operate on. Disconnect the base of the whip from the base of the antenna. This is the L1 section. We will measure 16 and 13/16 inches from the bottom of the first coil
Now on to the next section L2. You will need to unscrew the element from the lower element with the smaller allen wrench. Once you done that measure 12 and 5/8 inches from the bottom of the top coil down.
The last cutting is going to end up right where the foam pad is. At least on mine it was. It might be different on other antenna So I removed it gently. Made the cut and taped it back onto the rod just below the cut.
Almost done. Now reassemble all the elements, put the thing back in the fiberglass pole. Lock it down with the set screw and then fasten the 3 ground plane radials to the base. I mounted this antenna on the 5 foot mast in the back yard and checked SWR. They were
So far this antenna is running pretty good. The SWR are near flat. I will be testing the recieve on it for the next week as I drive around town. this is going to be the antenna I will be using for the Deltona, Florida GMRS linked repeater.
I hope this information has been helpful to some. If you have any questions or comments please email email@example.com
I see the price of this antenna does vary depending on where you order it from. Below are some links that you can get one from. Check the prices I paid less than $50 US for mine. You can even order one from HomeDepot , Lowes and Walmart. I used my gift card for mine so it was a good deal for me. I am not stating that this is the best antenna for GMRS use but I could not beat the price.
E-bay — Forget it they all think they have gold.
and of course google it. Prices change and look for holiday discounts and FREE Shipping.