Description
What the Tram 1180 Is and Who It Suits
The Tram 1180 is a pretuned dual band amateur radio antenna for mobile installation. It covers the 2 meter band from 144 to 148 MHz and the 70 centimeter band from 430 to 450 MHz, is rated at 150 watts, and terminates in an NMO base for vehicle mounting.
Pretuned is the operative word. Many dual band whips arrive requiring the operator to trim the element to length for the part of the band they use, which means owning an SWR meter and being willing to cut metal that cannot be uncut. Tram supplies this one already set for the stated ranges, which removes the step most likely to go wrong for a newer operator.
The listing records a weight of 8.8 ounces, dimensions of 36.5 by 1.5 by 1.5 inches, a black finish, a country of origin of Taiwan and a first availability date of November 14, 2018. The record shows 96 customer ratings averaging 4.4 stars at the time this data was captured.
The Gain Figures, and Why They Are Worth Something
Tram does something most antenna listings in this catalog do not: it publishes gain figures, and it publishes them with a reference. The stated figures are 3 dBd on the 144 to 148 MHz range and 6 dBd on the 430 to 450 MHz range.
The reference matters enormously. Gain can be quoted in dBd, referenced to a half wave dipole, or in dBi, referenced to a theoretical isotropic radiator. The two differ by 2.15 dB, and quoting dBi produces a larger number for the same antenna. A manufacturer that states dBd is using the more conservative and more meaningful reference. Converting for comparison, 3 dBd is about 5.15 dBi and 6 dBd is about 8.15 dBi.
Six dBd on UHF is genuinely useful gain for a mobile whip. Remember what gain means on a vertical antenna, though: it is achieved by flattening the radiation pattern toward the horizon rather than by creating energy. That is exactly what you want for terrestrial communication over flat ground, and it works against you in hilly terrain or when working a repeater on a mountain above you. Compare against the Comet CA-2X4SRNMO, which publishes no gain figure at all in its listing.
Construction and Mounting
Materials
The whip is stainless steel, which is the right material for something that lives on a vehicle roof through weather, salt and car washes. The base is chrome plated solid brass, and brass is chosen for machining quality and corrosion resistance rather than for strength. Tram also specifies a gold plated plunger type contact pin, which is the sprung connection between the antenna base and the NMO mount. Gold plating on that contact resists the oxidation that gradually raises resistance and degrades a connection over years outdoors.
NMO Mounting
NMO is the standard vehicle antenna mount used across commercial and public safety installations. Tram states clearly, at the end of its own bullet, that the mount is sold separately. Plan on buying an NMO base, whether hole mount, lip mount or magnetic, plus a coaxial cable assembly with the correct connector for your radio.
Ground plane is the other half of any mobile antenna installation. A vertical of this type relies on the vehicle roof acting as a ground plane, and mounting on a fiberglass surface or a small metal bracket changes both the pattern and the match. That is worth planning before drilling anything.
Highlights
- Pretuned for 144 to 148 MHz and 430 to 450 MHz, with no trimming required.
- Published gain figures of 3 dBd on VHF and 6 dBd on UHF, referenced to a dipole.
- 150 watt power rating, ample for typical amateur mobile transmitters.
- Stainless steel whip built for permanent outdoor exposure.
- Chrome plated solid brass base.
- Gold plated plunger contact pin for a durable low resistance connection.
- Standard NMO mounting, compatible with common vehicle bases.
- Light at 8.8 ounces, so mount loading is minimal.
Things To Consider
- The mount is not included. Tram states this directly. An NMO base and coaxial cable are separate purchases.
- The whip length is stated two different ways. The feature bullet says a 37 and a half inch stainless steel whip, while the product dimensions field says 36.5 inches. Half an inch is not important in practice, but it is another example of a listing disagreeing with itself.
- The Series field contains the entire product description rather than a series name, which is an import formatting artifact.
- No VSWR specification is published, and pretuned means set at the factory for the stated ranges rather than optimized for your specific installation. Checking SWR after mounting is still good practice.
- Gain works against you in some terrain. A higher gain vertical concentrates energy toward the horizon, which is not helpful when the repeater is on a hill above you.
- A 36 inch whip is tall. Parking garages, drive throughs and low branches are all real considerations on a permanently mounted vehicle antenna.
- Transmitting on these bands requires an amateur license in the United States. Receiving does not.
- 96 ratings at 4.4 stars is a modest but positive sample.
Who Should Buy It and Who Should Skip It
Buy the Tram 1180 if you are putting a dual band mobile radio in a vehicle with a metal roof and you want a simple, well specified whip that arrives ready to use. Published gain figures with a stated reference, a 150 watt rating, stainless and brass construction and a gold plated contact are a coherent specification, and the pretuned design removes the step that most often goes wrong.
Skip it if you need HF coverage, where a motorized antenna such as the Yaesu ATAS-120A is the relevant category, or if you need a base station antenna, where the Diamond X30A is designed for a fixed location. Buyers wanting a shorter whip for garage clearance should compare the Tram 1481, and the radio antenna category lists the rest.
