I used to have the infamous NavWorx ADSB which was a dual channel (978/1090) unit that was remotely mounted and connected to a single external antenna (RAMI AV-74).  When the FAA issued an AD requiring removal of the NavWorx, I immediately built and installed a remotely-mounted Stratux to take advantage of the already-present power, transponder, and antenna cabling left when I removed the NavWorx.

The Stratux required separate antenna inputs for the two radios, so I simply used a Y-splitter cable to connect them.  I realize there is some signal loss in doing this, but "someone" told me that the advantage of the single external antenna's improved reception (vs dual antennas inside the aircraft) would largely negate the small signal loss.  Evidently, this was true as the unit has always seemed to perform well!

I just recently noticed that there is an inexpensive splitter now available that incorporates a "SAW" filter:


My question is, if my present unit is working OK, is there any significant benefit to incorporating this splittler/filter into my installation?  To add to my confusion, I've seen posts on the Reddit Stratux forums recommend it and others say that the Stratux radios are well isolated and wouldn't benefit from this!

Any electronic whiz-kids out there to advise?  LOL!



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Assuming the comments about isolation in the Stratux are true, and your experience seems to bear this out, I would just leave it. Antennas are optimized for frequency. Although there are antennas with multiple elements that allow different range operations, those will normally have separate connectors. Yours has one, so it's a single element antenna optimized for one frequency range. However, it's very rare for an antenna to be perfectly matched, so there will be some overlap. Also, 978 and 1090 Mhz are so close to each other in frequency that the disadvantages of using one antenna for both are minimal. That's why your antenna functions fine for both ranges. The rules would change for ADS-B out, but there should be no reason why you'd need a new antenna for ADS-B in.

That makes sense to me, Bob - thanks!  The more I think about it, since I'm a "low and slow" flyer, it's not like I need any extended range or whatever benefit I might get from a more optimal antenna configuration.  My present configuration seems rock-solid, so I guess "if it ain't broke, don't fix it!" LOL!



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