I have recently accquired a couple of Diamond VHF/UHF dual-band portable antennas, each with different (or no) gain on 2m and 70cm amateur bands. I wanted to see to see how much of a difference they would make.
Advertised gain(s) for the antennas tested:
| Antenna | 144Mhz gain | 430Mhz gain | Connector |
|---|---|---|---|
| Diamond MR77 | Nil | 3.4 dBi | PL-259 |
| Diamond SRH771 | Nil | 2.15 dBi | SMA |
| Diamond SRH770S | 2.15 dBi | 4.5 dBi | SMA |
| Diamond RH770 | 3.0 dB | 5.0 dB | BNC |
Methodology
I put each of them on my Yaesu FT-3DR while standing in front of my porch, holding the radio at about head height; to test their reception, I tuned to a local CW beacon on 2m and check for the received signal strength.
The beacon used is the VK3RCW Morse Code Practice FM beacon, located in Glen Waverley, Melbourne, which is about 11km from my location.
Results
| Antenna | S-meter |
|---|---|
| Diamond MR77 | S5-S6 |
| Diamond SRH771 | S5-S6 |
| Diamond SRH770S | S7-S8 |
| Diamond RH770 | S8-S9+ |
As one would expect, antennas with higher gain have produced better received signal strength, with the Diamond RH770 producing S9+ in this test.
