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Do I need two nav antennae?

RandyAB

Well Known Member
I installed a cat whisker antenna on top of the VS for VOR/GS. I was talking about antenna placement with friend who is an electrical engineer and he said he installed both a cat whisker and an Archer wing tip antenna for each of his two nav radios so that he didn't have to split the signal.

Is signal loss with a splitter that significant that I should be thinking about two seperate antennae?
 
I installed a cat whisker antenna on top of the VS for VOR/GS. I was talking about antenna placement with friend who is an electrical engineer and he said he installed both a cat whisker and an Archer wing tip antenna for each of his two nav radios so that he didn't have to split the signal.

Is signal loss with a splitter that significant that I should be thinking about two seperate antennae?

Short answer - no.

Carl
 
Well, it sort of depends. In the case of a Garmin SL-30 nav/com, there is an internal splitter that sends 1/2 of the received signal to the navy receiver and the other 1/2 to the loc-gs function.

Other radios have separate nav and gs antenna inputs. In that case, you need a splitter if you only have one vor antenna. Or if you have multiple nav/gs receivers.

Each time you go through a splitter, the signal gets cut in half (or 3db). Using one splitter is not a big deal. The gs/loc signal is used when "close" to the airport environment and the VOR transmitters put out a much stronger signal for distance reception.

Another factor in our favor is that our modern receivers are very sensitive and can receive fainter /weaker signals than receivers of yesterday.

Another factor in received signal strength is antenna design and placement, but that is a different subject.
 
If you're splitting signal between two straight up nav radios, each gets 50%, but the glide slope tuner is a different frequency, so it's not using any of the energy from the nav signal. Should be only slight insertion loss for the splitter.

Only real downside to using a splitter would be, if you want full redundancy for IFR you'd need to duplicate the antennas.
 
Many builders have had good results with the archer antenna, when installed properly. Here is a thread on the subject.

It sounds like it is too late for you though.
 
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Do you NEED two Nav antennas? No. But IMHO if you can install two without much effort then yes. YMMV

:cool:
 
A diplexer combines or splits a signal based on frequency. A splitter splits all signal frequencies it can see. Use the right one....in your case a diplexer. But check the freqs and applications.
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Ooops. Read this - all the above appears to be wrong wrt your question. http://www.vansairforce.com/community/showthread.php?t=26063

Its not a spitter or a diplexer. Triplexer? T joint and diplexer? Yikes. Stein has some good comments on the thread above.....
 
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