2y ago

directional FM antenna + omni-directional DAB/FM antenna spliced together on one coax

I’m considering building a directional FM antenna for an FM station that has almost no signal in most of the house. Otherwise I must put the receiver near the window and put the antenna in a specific position. (related thread)

At the same time I am also tempted to build a omni-directional FM antenna that would also suit DAB frequencies (if possible). Since I would prefer to only run one coax cable throughout the house I guess I need to know if the directional and omni-directional antennas can simply be spliced together to share the same coax.

Is that feasible?

8 comments

No, I don't think that would work. Combining two antenna in one coax would combine the waveforms, which could result in destructive interference and much less signal. Even in the best case, you would lose any benefit of the directional antenna.
- Thanks for the tip. bummer to hear I have to run separate coax cables or come up with some kind of remote switch.
  
  A pair of diplexers (specific to the frequency ranges in question) would do the trick.
  But depending on what reception is like in your area it may be the case that your FM aerial fortuitously picks up sufficient DAB signal for a separate DAB aerial to prove unnecessary ?
I'm not from this community, so forgive me if I'm missing the point. If this is a regular fm radio station you're talking about then you can just stream it over the Internet
- Yes that’s true but the reason I listen to broadcast radio in the first place is because I’m on a limited connection. Broadcast radio consumes zero internet bandwidth. It’s also a lower carbon footprint (the transmission energy is spent whether I receive it or not).
  
  Your first point makes total sense, interesting to know, thanks. Your second point i would guess probably doesn't make sense. You'd probably have to stream an enormous amount of internet radio before it would create more pollution than is created by buying the hardware components that you're talking about.

8 comments