Fire Dispatch DrillFire Dispatch Drill

RACES ANTENNA FUNCTIONAL PRIORITIES

Must Communicate Securely Mounted Rapid deploy/removal Avoid O/H Obstructions Leave no marks

ANTENNA CONCERNS

Fire Dispatch DrillFire Dispatch Drill

What Didn’t Work Well Roof-top or Window mounted

5/8 λ or 1/4 λ antennas using a suction cup mount with/without hookup wire radials

Clip-On Window mount rubber duck antennas

Rubber Duck Antennas inside the Station or the FD vehicles

What Did Work Well 5/8 λ or 1/4 λ mag mount base

antennas sitting in contact with the diamond plate roof top.

1/2 λ antennas mounted on any surface

Suction Cup Mounts having pre-tuned brass rod radials

ANTENNA CONCERNS

- Aluminum Diamond Plate provides good match and gain- Magnetic base should be in direct contact with roof - Must be duct taped in place (not shown)-Good VSWR, 360 degree Coverage

1/4 λ Vertical Magnetic Mount Mobile Antenna

Recommended- Low profile- Low Drag- Adequate Gain

1/4 λ Suction Cup/Magnetic Mounted Antenna

Second Best Option

- Low profile- Low Drag- Adequate Gain

- 3 Brass Rods provide adequate ground plane- Length of Radial Rods need to be VSWR tuned beforehand- Coax cable must not run close to, or parallel to, radial rods- Can mount to any flat surface, conductive or not

1/2 λ Suction Cup/Magnetic Mounted Antenna

3rd Option

Totally flexible mounting while maintaining tune/match ie, can mount on conducting or non-conducting surfaces Radials and/or Gnd Plane are not necessary for match Must have internal L-Network to Match coaxial feedline 51” Tall, so has overhead obstruction issues Additional wind drag Gain, only if mounted on conducting surface or with Radials Eliminates Radial Rod complexity

Fire Dispatch DrillFire Dispatch DrillANTENNA RECOMMENDATIONS

It’s recommended to have a 1/4 λ magnetic mount antenna. It can be taped (use non residue duct tape) to an aluminum diamond plate roof, or attached to a steel roof. The metal roof provides a match and gain. The roof is high and enables a symmetric 360 degree pattern.

Short Antennas are best, but 1/2 λ antennas are easy to use if height is not a problem.

Avoid, if possible, mounting to non-conducting surfaces that lower gain and will require radials to obtain a match

If radials are necessary, use pre-tuned Brass Rod Radials and avoid using “hookup wire” radials