Bexar Operators Group Tests NVIS Antenna Theories

Garner State Park Entrance


A group of hams representing the Bexar Operators Group, and using the W5BOG callsign, drove over 100 miles to Garner State Park to operate during the 2008 Texas QSO Party (September 27-28) handing out contacts from Ulavde County.

The Camp GroundWhile we were there, we also tested our camping/deployment abilities and did some tests of NVIS antennas at different heights.

The Camp SiteNot wishing to get “soft”, we reserved a tent site to operate from rather than a cabin. Krissy, KD5YTN, set up the eight man tent while Bob, W2IK, began the station set-up using a 10×10 screened “EZ Up” as the main operating area.

Raising the AntennaThe antenna system was specially designed to allow us to operate from various heights by running the center point up or down like raising or lowering a flag. The ends ran on a weight system to keep the antenna taut. By varying the height of the antenna you could easily hear the noise floor decrease or increase. When a frequency was selected with an active station, you heard little in the way of signal degradation when compared to the lowering of the noise floor.

This experiment proved once again that even if your band of operation doesn’t allow for true NVIS signals to be generated, the increased readability was a positive factor for using NVIS antennas all the time for reliable short range communications.

We also noted that with nightfall, the international broadcasters were kept “at bay” by lowering the antenna from it’s maximum height of 27 feet to that of 5 feet.

Big Gun Astronomical TelescopeOn Sunday, several other hams dropped by to see us and operate. Yogie, KC5MIP, and Steve, KE5QFC, had been at the same park as part of “A Night With The Stars” sponsored by the San Antonio Astronomical Association that Saturday evening and stayed the night.

Unexpected Guests

Guest OperatorsFrank, KE5RYJ, from Uvalde and the Coyote Amateur Radio Club also came by to see our operation and get a firmer grasp on NVIS antenna design and operation.

Bob W2IK operating during contest
Using our club call, W5BOG, we casually managed several hundred contacts while testing our theories concerning NVIS wave propagation on both 40 and 80 meters.

The Buzzard sitting on our antenna mast
We had a few uninvited “guests” (in this case a vulture!) who decided to hang around in case the bands died. They even had the nerve to perch on my antenna mast!

At least they didn’t want to operate!

Krissy Cooking For Us

While we were camping, it was a great chance to try out the new Coleman burner/grille. This had recently been purchased to replace an older two-burner unit. The built-in grille made cooking burgers a snap. No more fighting with my antique stove.

Yogi KC5MIP operates during the contest

Everyone had a great time and exchanged ideas and took turns operating during this event.


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