Can you tune a quadrifilar helix antenna for a frequency range vs. a specific frequency?
There are a lot of documents as well as calculators for designing and tuning these home made antennas to a specific frequency. However as you know, sometimes we have to change frequencies on the field. Obviously making multiple antennas tuned to all of the potential frequencies is not practical so I would prefer to tune one to a range. Being home made antennas its not a stretch to imagine that the tolerances of these "tuned" antennas can vary, but they still seem to work, at least on YouTube. This leads me to believe that there is some forgiveness with the design.
My application is with the Altus Metrum TeleGPS trackers. I use the TeleBT tethered to my Android and my unidirectional Yagi when out recovering and if I am not at my setup table for launch. However I also have the TeleDongle, which allows me to use my Mac while sitting at my setup table. I would prefer this to be a stationary setup even though I realize that I am giving up some range for the convenience.
So I have been kicking around the idea of fixing an extension pole mounted omnidirectional antenna to one of the legs on my tent, specifically a 70cm quadrifilar helix tuned for 434.55 - 435.45 full range of the TeleGPS units.
Do any of you hams know if this is possible?
There are a lot of documents as well as calculators for designing and tuning these home made antennas to a specific frequency. However as you know, sometimes we have to change frequencies on the field. Obviously making multiple antennas tuned to all of the potential frequencies is not practical so I would prefer to tune one to a range. Being home made antennas its not a stretch to imagine that the tolerances of these "tuned" antennas can vary, but they still seem to work, at least on YouTube. This leads me to believe that there is some forgiveness with the design.
My application is with the Altus Metrum TeleGPS trackers. I use the TeleBT tethered to my Android and my unidirectional Yagi when out recovering and if I am not at my setup table for launch. However I also have the TeleDongle, which allows me to use my Mac while sitting at my setup table. I would prefer this to be a stationary setup even though I realize that I am giving up some range for the convenience.
So I have been kicking around the idea of fixing an extension pole mounted omnidirectional antenna to one of the legs on my tent, specifically a 70cm quadrifilar helix tuned for 434.55 - 435.45 full range of the TeleGPS units.
Do any of you hams know if this is possible?