Product Review

 

External Antenna for all Garmin GPS models.

 

 

Product Details

Model:                                    RF Design GPS-MCX/M-5 External Antenna

Supplier:                                 RF Design, Cape Town, Midrand and Durban

                        http://www.rfdesign.co.za

Price:                                      ~R160 delivered Durban including VAT

Full Specifications:               See Appendix

 

 

 

 

Executive Summary

 

A well-manufactured product that is very reasonably priced and does an outstanding job, dramatically improving satellite reception and track accuracy.  Highly recommended.

 

 

Detailed Review

 

The unit arrives securely protected and packaged.  No user assembly required.

 

The magnetic mount is well constructed and is stronger than required, so dislodgement of the antenna by branches etc. is highly unlikely. 

 

The BNC connector (required for the GPS V) is of good quality and fits well.

 

The unit can be supplied with a cable length of the purchaser’s choice.  This will depend on the user’s vehicle and the desired mounting position.  Standard length is 5m, and my supplied length was 9m.  When fitted to the centre of the roof of my Ford D/C and routed through the rear sliding window and along the side of the cabin to the centre of the dashboard the surplus was approximately 1.5m.  The co-axial cable used is low-loss RG174U, so the additional signal attenuation due to the extra cable length is negligible.

 

Once connected it is immediately apparent that this unit is out of the top drawer.  Virtually every satellite’s signal was full strength as shown on the GPS display.  Invariably all satellites above the horizon were received, even those at very low elevation angles.  I was surprised that even the low elevation satellites were received full strength.  These signal strengths were never seen with the internal antenna, except for overhead satellites.  It is a pleasant surprise to be receiving 10 satellites continuously!

 

TTFF (Time to first Fix) was significantly improved.  Hot start was invariably less than 10 seconds, and cold start (unit not used for a few days) was less than 30 sec.  Time to settle down to a low EPE (Estimated Position Error) was also fast, a major improvement.

 

EPE while driving was an almost continuous 4m, with occasional drops to 5m or 6m when travelling through wooded areas, and tree-lined roads.  However, this was not often seen, and the user can be sure of 4m EPE virtually all the time.

 

Comparing tracks using the internal and external antenna easily showed more accuracy with the external antenna.

 

The price is extremely reasonable when compared to the Garmin manufactured item.

 

I would have no hesitation in recommending this unit.

 

 

 

 

 

 

Reviewer:                             Peter Tiedt                (bushman@ecotracs.org)

Date:                                      December 2004.

APPENDIX

 

Detailed Specifications

 

GPS Active Antenna

Part Number:                                      GPS-MCX/M-5

Supplier:                                              RF Design

Supplier Website                                http://www.rfdesign.co.za

Price                                                    R134.88 (ex vat) ex factory

Landed in Durban:                              approx R160 inclusive of VAT and S&H

 

General:

Frequency                                           1575.42 ± 3 MHz

VSWR                                                 1.5 Max.

Bandwidth                                           10 MHz Min.

Axial Ratio                                           3 dB

Typical Impedance                              50 Ω

Peak Gain                                           4 dBic Min.

Gain Coverage                                    ≥ -4dBic at –90°≤ θ ≤90°(over 75% volume)

Power Handling                                   1 watt

Polarization                                         RHCP

 

Amplifier Module:

Amplifier Gain                          27 dB Typical

Noise Figure                                        1.5 dB Typical

Output VSWR                                     2.0 Max.

DC Voltage                                          DC 3.0 V to 5.5V

DC Current                                         22 ±3 mA

 

Mechanical:

Weight (Without Cable)                      46 grams Max.

Size                                                     50 X 50 X 17 mm

Cable                                                   5M RG174 (or user specification)

Connector                                           MCX Male Straight plug (or alternates)

Mounting                                              Magnetic base

Housing Colour                                   Black

Label                                                   Clear with S/N#

 

Environmental:

Working Temperature                         -40°C< T< +85°C

Storage Temperature                         -50°C< T< +95°C

Vibration                                              Sine Sweep,1G(0-P), 10-150-10Hz each axis

Humidity                                              95%~100% RH

Weatherproof                                      100% waterproof

 

Options Available:

 

Connector                                           MMCX, SMA, BNC

Connector Configuration                     Straight or Right Angle, Male or Female

Cable Length                                       As required

 

 

 

 

 

DIAGRAMS