'tis possible that it could have that kind of gain, as the reference
point (compared to Dipole (dBD), Isotropic (dBI), or WET NOODLE dB(?))
was neglected in the gain statement! In fact might be even better than
27 dB (?) when compared with a wet noodle, but that has no bearing on
any credible gain! That ANY antenna would have a gain of some 400
TIMES a dipole, or even an isotropic (Point source) would take up
considerable acreage at 2 meters! A typical moonbounce station uses
about 20 dBD gain , and these are multiple yagi antennas.
see: http://www.bigskyspaces.com/w7gj/longyagi.htm for a 19 dBD gain
2 meter yagi, and note the length! (98-1/2 feet long!)
and also look for VE7BQH - These guys have verifiable antenna gains
and know their stuff! when ANY antenna claims more than 10-11 dB I
gain ,be very suspicious of the claims, also, make sure to see WHAT
that gain is compared (referenced) against! This is at least one of the
reasons that the ARRL is loath to allow gain claims by advertizer,
unless they have been verified by independant sources. Jim NN7K

Pierre Desjardins wrote:
Hi to all

I read somewhere that the dual rhombic could give a gain of almost 27
db using these dimension for 144,2 mHz:

L1- 29.5 ft, L2- 50.67 ft, X- 52.2 degrees, Y- 37.7 degrees, R1/2 660
ohms noninductive, Ht: 12.29 ft, Elevation angle: 7.5 degrees,
Vertical beamwidth: 5.5 degrees and Horizontal beamwidth: 8.5 degrees.

Has anyone ever verified this? Here, using simulation with EZNEC+, I
get about 15 dBi in free space and much lower on real ground. Am I
missing something?

Thanks for your answers

73 de Pierre VE2PID