“If your SWR is HIGH on 80 meters and it increases when you spread the coil then you need a coil with one
more turn for a higher Micro Henry value”.
It’s a balance of the SWR between the bands and this takes a few minutes of adjusting to find that sweet spot.
If it is under 1.5:1, you’re done. If it isn’t, you may have to compromise between the 40 and 80 meter settings .
Please adjust your antenna for the LOWEST SWR for Absolute Maximum Performance!
160 meter antenna dual shunt coil enclosure install
“WARNING”, If you switch the dual shunt coil relay while transmitting
you will Damage the relay contacts!
After removing the dual shunt coil enclosure lid you will then be able to use a hex or Allen wrench to hold the
button head screws and remove the two holding nuts on the rear of the enclosure. The two nuts can now go into
your favorite storage bin for your next project.
The 160 meter shunt coil is upper right with 80 meter shunt coil
on left side inside enclosure. The dual shunt coil relay is located at the bottom of the enclosure.
There are two locations on the antenna that you can mount the dual shunt enclosure. As seen in the photos, the
small button head screw above the white Delrin insulator is a 10/32 thread and the button head below the white
Delrin insulator is a ¼-20. There are three locations for 10/32 button head screws, they are 120 degrees apart
from each other around the antenna.
The black #10 gage wire the feeds RF current to the stainless tube is one location that cannot be used, the other
two locations around the antenna are available. After locating your favorite side of the antenna to mount the
shunt coil enclosure, remove the 10/32 and the ¼-20 button head from the antenna. With the supplied button
head screws in the dual shunt enclosure, align the enclosure to the antenna then tighten the screws. Now connect
the control cable and have someone switch the 80/160 meter switch that is located on the top of the hand control
box and listen for the relay to energize, you will hear a click. With the relay tested you can now install the
enclosures cover.
Do not transmit while switching the 80/160 meter dual shunt coil relay!
