Hacked together an ultraportable HF antenna system to work well between 3.5Mhz - 200 MHz (80 meters - 2m) frequencies. Basically took a coil loaded GRA-1899T antenna with telescoping antenna, added some off-the shelf BNC adapters and did some minor hacking. To make it work I had to remove the center connector from two of the BNC adapter s(marked with an X in the diagram). Then added a short-circuit BNC connector, which connects the otherwise floating center connector from the bottom half to ground/shield enabling the counterpoise. Added two additional telescoping elements for the counterpoise and we have a complete system.

The thing I like about the approach is the modularity. For example I can remove or add normal t-connectors to change the number of counterpoises used. The setup pictured uses 2 counterpoises but it would be trivial to setup 1 to 4.

Also the short circuit connector (pictures here as the black and teal connector with the short circuit in it) can allow me to do multiple things if i want to get more complicated. For example if I want to remove the short circuit I can replace it with coils or capacitors for additional tuning. I can also leave it as is but connect an earth ground to it to improve the effectiveness of the counterpoise.

A final note, the loading coil attached to the radiating part of the antenna has a jumper with 6 different positions. This lets you manually adjust the size of the loading coil for different frequencies. Fine tuning is accomplished by changing the length of the antenna itself.

#Science #electronics #RF #radio #Amateur AmateurRadio #HAM #HAMRadio ## @Science

@freemo Sounds cool, but WAY above my paygrade :) Does it mean my neighbor two doors down, who has amateur radio operator license plates and a whole garage for his radio set up can listen in on my house? LOL