/diy/ - Do It Yourself

>>1623494
>>1623910
>>1623889
>>1624461
I think I understand your question and I think the short answer is that you've misunderstood how a coaxial cable works and, to a certain extent, what the transmitter is doing. The balun is a minor detail to work out later.
1. Conceptually, the transmitter sits "in the middle" of a long wire and induces an alternating current into the middle. The two directions of wire can each be used for an antenna.
2. You could just ground one of them if you wanted, but that would waste half your power.
3. The coaxial cable actually carries a voltage in BOTH the core and the shielding. In fact these are where the TX's two outputs get hooked up.
4. This second current explains how the cable 'shields' --- the two conductors BOTH emit radio waves, which then exactly cancel each other out.
5. When people say the coax shielding is supposed to be "at ground potential" they're talking about the outward-facing side of the shielding. The gist of it is that only the inner-facing surface of the shielding gets a current; the RF current is unable to penetrate more than a couple millimeters of copper due to the so-called "skin effect". Of course it is the inner, powered part of the shielding that you attach to the antenna.