P.S. Note that the measurements shown in my picture are for a wide-band (to cover both bands) receive only antenna whereas an antenna for transmit/receive on the 900 MHz band should be a little shorter.  (i.e. twice the length of your monopole antenna)

"You're less likely to go wrong sticking with a more conventional solution"

 

It looks like you have enough room for a dipole antenna (see my previous picture) if you ever decide to upgrade.  It will at least give you better coverage for the volume on the other side of the virtual ground plane and should be more cylindrically symmetric.

 

Steve Stearns

O235 Longeze

Boulder / Longmont CO

 

On Tue, Jun 23, 2020 at 9:04 PM Marlon Gunderson <sondergun@...> wrote:

Thanks James, you're right, this is totally experimental and may not work reliably for someone else. I have not done any kind of formal testing, just flown with it for 3 years and checked the FAA ADSB performance test a couple of times a year.  It hasn't shown anything other than 0% failures (of about 10K pings/hr) when I've checked but there's nothing to say I won't see some failures in the future. You're less likely to go wrong sticking with a more conventional solution.

-Marlon

 

On Tue, Jun 23, 2020 at 6:36 PM berkut13 <berkut13@...> wrote:

It may indeed “work”, but the radiation pattern is going to be significantly affected by the asymmetrical ground plane radials.  Could cause some reception issues by ground stations in certain directions. No way to really know without extensive testing.

 

-James

 

From: members@canardzone.groups.io [mailto:members@canardzone.groups.io] On Behalf Of Marlon Gunderson
Sent: Tuesday, June 23, 2020 3:26 PM
To: members@canardzone.groups.io
Subject: Re: [Canard Zone] ADSB In - Classic Cozy 3 Antenna Placement Experience

 

Virtual ground plane in the strake cavity has worked well for me for an Echo UAT. Good separation from the Mode C antenna under the front seat.

-Marlon  Cozy3  N129GR

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• 2016-03-11 14.25.32.jpg
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