Uploaded October 2021 | Updated September 2026, 1 hour ago
ICOM IC-705 transceiver and Elecraft AX1 portable (pocket) antenna could be a good pair for outdoors operations! Unfortunately, the AX1 is not a resonant antenna on any ham radio band, it does require the antenna tuning unit, and the ICOM IC-705, unfortunately, is lacking one!
Luckily, there is a simple yet extremely effective solution : it's the Capacity Hat for the AX1! The capacity hat is known for decades in amateur radio antennas systems. It increases the radiation resistance, which means increased efficiency, makes the antenna much more broadband which compensates for the loading coil's imposed "narrow-bandness" of the antenna.
For this experiment, I used a simple capacity hat made of few copper wires, and this allowed for the nice resonant work of the AX1 on 20,17 and 15 meter bands while connected to the IC-705.
This mod could surely be used with any other QRP HF radio with no ATU in-built. I, for instance, am going to use it with my little QCX-mini 20 transceiver in addition to the IC-705 ( and Elecraft KX2 of course which has got a great ATU in-built :) )
There is nothing that could prevent us from making bigger or differently shaped hats and get short vertical whips resonant on 30 or 40 meters. If you done that, please share your experience with us in the comments section! Also, please consider subscribing if you'd like to see more stories like this.
My channel recently reached the first serious milestone - 1000 SUBS! A great many thanks to everybody who subscribed to my channel and, thus, helped the channel grow!
73! Linas LY2H
ICOM IC-705 transceiver and Elecraft AX1 portable (pocket) antenna could be a good pair for outdoors operations! Unfortunately, the AX1 is not a resonant antenna on any ham radio band, it does require the antenna tuning unit, and the ICOM IC-705, unfortunately, is lacking one!
Luckily, there is a simple yet extremely effective solution : it's the Capacity Hat for the AX1! The capacity hat is known for decades in amateur radio antennas systems. It increases the radiation resistance, which means increased efficiency, makes the antenna much more broadband which compensates for the loading coil's imposed "narrow-bandness" of the antenna.
For this experiment, I used a simple capacity hat made of few copper wires, and this allowed for the nice resonant work of the AX1 on 20,17 and 15 meter bands while connected to the IC-705.
This mod could surely be used with any other QRP HF radio with no ATU in-built. I, for instance, am going to use it with my little QCX-mini 20 transceiver in addition to the IC-705 ( and Elecraft KX2 of course which has got a great ATU in-built :) )
There is nothing that could prevent us from making bigger or differently shaped hats and get short vertical whips resonant on 30 or 40 meters. If you done that, please share your experience with us in the comments section! Also, please consider subscribing if you'd like to see more stories like this.
My channel recently reached the first serious milestone - 1000 SUBS! A great many thanks to everybody who subscribed to my channel and, thus, helped the channel grow!
73! Linas LY2H
