Wayne,

 

After poking around the manuals, the internal diplexer appears to allow for the sharing of nav antennas as is somewhat common.  I did not see the radio rear but I would guess there are only 3 antenna connectors - Comm, GS and the combined loc/vor.  Certainly the 530W is like the 430W where that is also true. 

You really are planning for pretty serious dual loc/ils/vor/gs coverage whilst also having a very powerful WAAS GPS with vertical guidance to many GPS approaches.

 

I am not saying you shouldn't have such coverage, but it does require more thought on nav antennas.  Note that the SL30 converts loc/vor to some internally usable form and thus those two receivers can utilize one antenna since their function does not overlap (except when another nav radio is added).  The GS is a separate antenna connection but it may share a nav antenna with some degradation.  The 530W probably requires an external diplexer if the loc/vor and gs are sharing an antenna.  Tying all four radios together on one nav antenna....hmmmm...

 

A typical GS antenna would be horizontally orientated perpendicular to the flight path and might be center tapped foil about 10 inches long.  Mine is placed in the leading edge of the stub wing on my 320.

 

I have a single comm antenna in the tail with the 430W and Terra comm radio antennas externally switched (comm radio selector) and isolated when the transmit key is depressed.  BTW, Note that the Canadians require that your passenger must be 52 inches from the comm antenna before you can transmit (You, as the pilot need only be 24" away because they believe your head is harder or is wrapped in tinfoil...........).

 

The nav loc/vor antenna is located in the horiz stab.  Of course, the 430W is the only nav radio so I don't need to split the signals or share the loc/vor with the gs antenna.

 

Scott Krueger

  

 

Hi All,
 
Installing my avionics and its time for antennas, I installed a comm antenna in the vert/stab years ago and everything is closed back there.
I am installing a S/L30 Nav/Com which has an internal diplexer and the manuel says not to install an external diplexer, however I am thinking
they are talking about using an external diplexer for one antenna for Nav/Com. I am also installing a GNS530W and in the rear of the unit there
is a place for a Nav and GS antenna. My plan is to install a Bob Archer VOR antenna in the ceiling of the baggage area and that would give me
one Nav ant and one Comm ant. I would use a splitter coming from the Nav ant and connect to the Nav port on the S/30 and to the Nav port
and the GS port on the 530W GPS which has two different ports for GS and Nav. I would use a T/R switch for the com on the S/L30 and the
com on the 530W GPS. I emailed Bob about this installation and he said he believed it would be ok but didn't know if the GS connection fr the
splitter to the 530W would completely rob the signal from the S/L 30. Please give me your recomendations as I know there are many 2 place
Lancairs flying with no antenna problems.
 
Thanks in advance , Wayne
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