GP4 Shortwave 4-Band (7/14/21/29M) Vertical GP Antenna

GP4 Antenna, SWR Adjustment Tips and Methods. GP4 antenna installation location should be on flat ground. It should not be installed on high railings or small pointed surfaces, and the height should not exceed 0.5 meters. The GP4 antenna requires a ground net to work properly.

Without a ground net, the antenna cannot function. There are two types of ground nets: one is about 5 meters long × 4 pieces for matching 7MHz operation, and the other is about 2.5 meters long × 4 pieces for matching 14M/21M/29M operation. GP4 antenna SWR adjustment method: align the three holes on the antenna body and install the airplane wings correctly; no further adjustments are needed. SWR adjustment is done by trimming the ground net length to match the SWR.

To adjust 7M, trim the 5-meter ground net; to adjust 14/21/29M, trim the 2.5-meter ground net. The GP4 antenna can also use metal railings as an equivalent ground net.

It may work, or it may not match the SWR correctly. You can try moving the antenna's position.

The GP4 antenna should ideally be fixed with rivets. Screws are only for temporary installation and testing; for long-term use, it is not recommended to connect the antenna body with screws.

The 5-meter radials are used to match 7M, while the 2.5-meter radials are used to match 14M, 21M, and 29M. The antenna itself does not need adjustment; adjusting the 5-meter ground radials will tune the 7M SWR, and adjusting the 2.5-meter ground radials will tune the 14M, 21M, and 29M SWR. It is recommended that the GP4 be installed at a height of less than 0.5 meters.

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