On three separate occasions the Tech Bench Elmers' have conducted two meter wavelength band antenna tests on a dry lakebed in the Mojave desert. These antenna tests were conducted in a scientifically controlled manner and on each separate occasion cross confirmed the results of the earlier tests. These tests were also arranged such that the radiation angle of the antennas under test could be assessed not only for their performance on the horizon but, also at an elevated angle. These tests were conducted on the dates of Nov. 26-28 1993, May 28, and 29th of 1994, and May 1995. The measured results of these first three tests are chronologically listed below. All readings are in -dbm (Decibels below 1 milliwatt).

1/4 Wavelength Ground Plane fabricated by WA6BFH                29.50 Dbm

1/2 Wavelength  aluminum "J" fabricated by WA6BFH               30.25 Dbm

1/2 Wavelength Stainless Steel "J" by KD6IES                    29.00 Dbm

1/2 Wave over 1/2 Wave "J" by KD6IES                            29.25 Dbm

Hustler G6144B commercial collinear omni                        25.75 Dbm

Base matched 1/2 Wave omni by KC6PNY                            28.75 Dbm

M-Squared 7 element Yagi-Uda beam                               19.00 Dbm

6 element Yagi-Uda antenna fabricated by KD6ZCN                 20.50 Dbm

Mobile Antennas tested

Larson Mfr. 5/8 Wave omni on automobile rooftop                 28.50 Dbm

Diamond Mfr. 144/440 MHz. (tested on 144 MHz.) 29.75 Dbm

1/4 Wave "Home-brew" omni fabricated by KC6PNY 29.75 Dbm

MFJ Mfr. 1/4 Wave omni provided by KD6JNB 30.25 Dbm

The above listed antennas were tested in Nov. 1993. A summary comparison follows the accumulated data.

The below antenna test results were taken or measured at two separate signal data received sites. Site A was at an elevated location at the top of Fremont Peak. Site B was located on the same horizon elevation (2680 Feet above sea level) as the antennas under test.

                                                            Site A          Site B

1/4 Wave Gnd. Plane by BFH (Same as in Nov. '93 test)      -26.0 Dbm       -51.5 Dbm

1/2 Wave Alum. "J" by BFH   (Same as in Nov. '93 test)     -27.5 Dbm       -52.0 Dbm

Copper 1/2 Wave "J" by BFH                                 -27.0 Dbm       -51.2 Dbm

Two 4 Element KLM Yagi's phased (one beam skewed)          -17.0  Dbm      -42.0 Dbm

Let us now observe and compare the test result analysis of the first two tests. Similar comparisons can also be made to the third test.

Result analysis can be made by subtracting the decibel gain value of one antenna compared to another. One example shows that by subtracting the - Dbm value of the M-Squared 7 element Yagi from the 1/2 wavelength aluminum "J" antenna we observe the following mathematical result, 30.25 - 19.00 = 11.25 Db's. Eleven decibels is a realistic gain figure for the beam antenna as compared to the end-fed "J" dipole.

If we similarly compare the 1/2 wave "J" to the Hustler collinear omni our result is observed as follows. 30.25 - 25.75 = 4.5 Db's. Keep in mind that the only data results that could be recovered from the first test of Nov. '93 were at the elevated Fremont Peak site. No data could be received from the horizon site. On the horizon a theoretical gain figure of 6 decibels over a dipole should be observed, at an elevated location this would be somewhat less, such as the 4 1/2 Db's observed. A 1/4 wavelength Ground Plane should display a higher angle of radiation than the dipole. If we compare the 1\2 wavelength "J" dipole to the Ground Plane the result is 30.25 - 29.5 = 0.75 or 3/4's of a decibel, almost 1 Db better than the dipole when observed from the elevated angle. A further point of interest showed that Copper constructed soldered "J" antennas proved to be better efficient having less resistive feedpoint loss than the Aluminum constructed "J's" which were bolted together.

On the second test of May '94 a comparison of the Aluminum and Copper "J's" showed a mathematical difference of 0.8 decibels (52.0 - 51.2 = 0.8). Almost 1 db better than the bolted antenna. When comparing the performance of the Copper J to the Ground Plane as observed from the elevated site, we see a 1 Db difference at the higher elevation angle from the Ground Plane (27.0 - 26.0 = 1.0).

Cliff KD6AUN and Matt KE6ALM organized this test series and the results are listed below. The test data was taken by a different procedural method than the earlier tests. In this test the receiver sites inserted appropriate amounts of signal attenuation to match readings against the reference antenna listed. Receive site personnel were only aware of the first time the reference antenna was used! Note the consistency of the average signal difference between the elevated and horizon level receiver sites!

Antenna description and construction    Horizon          Elevated        Difference

Reference Copper J by KE6ALM                44db           51db            7db

1/2 wave over 1/2 wave J by KO6JH           47db           52db            5db

Ref. J by KE6ALM                            43db          49.5db          6.5db

Ref. J KE6ALM (mount straightened)          44db          49.5db          5.5db

1/2 over 1/2 wave J (top 1/2 removed,       43db            50db            7db
Q-Line match re-adjusted)

1/2 wave J by KD6IES                        44db            50db            6db

Top loaded (Cap. hat) 5/8 wave by KN6VR    38.5db          44.5db           6db

DDRR by KD6IES                              12db            34db            22db

DDRR cross polarized directed at Hor. site  28db            33db            5db

DDRR same Pol. aimed between sites          30db            30db            0db

DDRR same polarity aimed at elevated site   30db            22db            7or8db
Reading at elevated site was plus or minus 1db

Roll up J by KO6JH                          44db            47db            5db

Ref. J by KE6ALM                            44db            49db            5db

4 Ele. Cubicle Quad by KO6JH	
Above pointed at Horizon site_ _ _ _ _ _ _  51db             34db            17db 
	
Above pointed at Elevated site              16to19db         49db            40to44

Above aimed between both sites              37db             33db            4db

Above aimed 180 degrees to Horizon site     36db             51db            15db

Above aimed 180 degrees to Elev. site       47db             52db            5db

1/4 wave Mag. mount by Valor                36db             41db            5db

Above Ant. while monitored on Bird 43      36 db             42db            6db

5/8 wave by Radio Shack                     37db             44db            5db
This antenna displayed reactive fluctuations

1/4 wave Mag. mount by KO6KS                37db             44db            7db

2M/70CM/23CM by Diamond                     37db             44db            7db

2M/70CM by Diamond                          38db             44db            6db

Ref. J by KE6ALM                            42db             47.5            5.5db

1/2 wave "duck" by "MFJ"                    36.5db           43db            6.5db

Icom FA-3BA Tri-bander                      24db             32db            8db

HTX-202 Hand held                           31db             39.5db          8.5db

Super Slender SH-5 by Comet                 39db             39db            0db

Miracle Baby CH-32 by: Comet                5db              14db            9db

2M/70CM  by Larson                          20db             29.5db          9.5db
Above has 5 inch whip and is 7 in. overall