The K8RSC 40 Meter Gamma Fed Vertical

The second antenna I built was for Rick K8RSC. I have included some construction photos, graphs, as well as photos of the installation at Rick’s location. He sits high on sandy ground, on a peninsula in Lake Michigan.  Rick laid out 28 ground radials and bonded them to the ground rod and antenna. Much to my amazement there is very little difference in SWR, bandwidth, or impedance characteristics.  Rick put more time into optimizing the band width as a whole, where as I shot bit more at the top of the band, that and I believe even with the wetlands at this QTH,  Rick achieved a better ground plan then I did. Radials are everything to a vertical antenna.  This antenna modeled at about 94% efficient. There was some differences in construction method and materials but the same basic theory used in the first antenna was applied here. Both of these antennas are aluminum tubing from DX Engineering. The aluminum plate is .250″ thick, the angle aluminum is 1″x .125 thick. They are TIG welded to ensure good conductivity and strength. I was talking to Rick K8RSC and he informed me that he worked all  13 Original Colony States over the Independence Day holiday on 40 Meters in 42 minutes. Rick says he truly enjoys his 40 gamma fed vertical. He also stated that they all responded on the first call, he is running the Yaesu FTDX-1200 and an Ameritron amp with a single 3-500Z tube.

SO-239 and 150 pf 7.5 KV Capacitor.
Main element, housing, and gamma insulator.
Ground radials at K8RSC’s
Base of antenna at K8RSC’s
Location of Current Balun
Gamma Shorting stub at K8RSC’s

 

SWR 7.000-7.300 Mhz.
SWR 5.000-10.000 Mhz.
Smith Chart 7.000-7.300 Mhz.

I am going to start the manufacture of the base section of this antenna in the near future. I will sell them through my corporate identity Duir Life Skills Training LLC. I am working on a materials cost structure to determine a selling price. If you are interested email me at duirlst@gmail.com and I will keep you informed.