06-03-2010, 01:16 PM
There are three antenna connections in the battery compartment of the 41-81 I have just finished.
The lower terminal connects to one side of the loop, and the blue wire from the 1st IF coil solders to it.
The other side of the loop solders to the middle terminal, and the green wire from the tuning capacitor solders to the upper terminal. Connecting the middle and upper terminals are two curved pieces of metal that may once have been springy to touch one another, but they no longer touch and have lost most of their spring force. One of these curved pieces (on the side connected to the loop), is insulated except at the contact area at the top.
I think originally the two curved springy pieces of metal touched to connect the green-wire terminal to the loop, but if you inserted plugs from an external antenna, the plug would separate the two curved springy pieces, disconnect that end of the loop from the green wire, and connect the external antenna to the green wire. This is similar to the function of a modern headphone jack that disconnects the speaker when you plug in the headphone.
Reception is terrible if the two springy pieces don't touch. If you connect the springy pieces at the top with an alligator clip, reception is good. To fix this, I will probably solder a short between the upper and center terminals to connect the loop to the green wire. I don't expect to use an external antenna, and anyhow, I don't know what sort of antenna or plugs to use.
The lower terminal connects to one side of the loop, and the blue wire from the 1st IF coil solders to it.
The other side of the loop solders to the middle terminal, and the green wire from the tuning capacitor solders to the upper terminal. Connecting the middle and upper terminals are two curved pieces of metal that may once have been springy to touch one another, but they no longer touch and have lost most of their spring force. One of these curved pieces (on the side connected to the loop), is insulated except at the contact area at the top.
I think originally the two curved springy pieces of metal touched to connect the green-wire terminal to the loop, but if you inserted plugs from an external antenna, the plug would separate the two curved springy pieces, disconnect that end of the loop from the green wire, and connect the external antenna to the green wire. This is similar to the function of a modern headphone jack that disconnects the speaker when you plug in the headphone.
Reception is terrible if the two springy pieces don't touch. If you connect the springy pieces at the top with an alligator clip, reception is good. To fix this, I will probably solder a short between the upper and center terminals to connect the loop to the green wire. I don't expect to use an external antenna, and anyhow, I don't know what sort of antenna or plugs to use.
John Honeycutt
