sirio 827 5/8 vs gainmaster

[The Man from Uncle]

as you all already know ...... the fiberglass is just viagra to hold the copper wire inside that is actually the antenna . i think i remember some comments about the matching network used in the 99/2K doesn't make efficient use of ground elements added to them . i know the GM doesn't use ground elements and its said to not need them ....... but i wounder how it would react to having four 9 footers added to its feed-point horizontally or sloped ?? has anyone thought of trying it on theirs ?

By adding ground radialials below the antenna feed point, this will change the input impedance from 50 ohms to whatever???. Your coax that is feeding the antenna is acting like a counterpoise (ground plane) so adding radials/Guy wires could throw off the match thus requiring you to use an antenna tuner. Keep in mind, every coax connection will cause aproximately 1/2 db of loss, being the GM is factory tuned and Isn't tunable by the consumer, adding an antenna tuner to compensate the input impedance, your going to end up chasing your tail on this.
If it isn't broke, dont fixit. If the Sirio antenna engineers felt the antenna needed ground radials, then those would have been made an option.

 

[AudioShockwav]

Keep in mind, every coax connection will cause aproximately 1/2 db of loss,

Good quality PL 259 connectors have very little loss at 30 Mhz and below.
Even at 450 Mhz a good quality PL 259 only has 0.09 db loss measured with a HP8753 RF network analyzer.

73
Jeff