ADSB

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2066
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Name: Mac Forbes
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Aircraft Type: '46 Cessna 140
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Re: ADSB

Post by 2066 »

8233 wrote: Sat May 26, 2018 3:57 am Is there a consensus on the best place to install the GPS antenna? Most practical, easy to get to, etc,,

Thanks

...not sure it's the best, but mine fits well exactly where my old Loran C antenna was, near/rear of the spar carry-through. That spot keeps it the recommended distance from both the comm and elt antennas & is relatively easy to access (& no need to drill another large hole)
IMG_0510.JPG
IMG_0510.JPG (245.04 KiB) Viewed 5503 times
. Mac
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8233
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Name: David Freeland
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Re: ADSB

Post by 8233 »

Thank Mac, that's very helpful and I think makes great sense. Since I have never had more than a Comm and ELT antennas (I have 2 com antennas on top), I'll need to drill a hole but that looks as good as any. Especially if it's easy to get to. My plan is to go with the Stratus ESGi setup by the way.
David Freeland - CFII
1972 Bellanca Super Viking and 1946 Cessna 120
2066
Posts: 600
Joined: Tue May 01, 2018 7:00 am
Name: Mac Forbes
Location: North Carolina
Aircraft Type: '46 Cessna 140
Occupation-Interests: Retired - Current 120-140 Assoc. NC Rep.
Contact:

Re: ADSB

Post by 2066 »

You'll be pleased with the Stratus package -- good value & proven. Of the several practical and "affordable" options out there for our kind of flying, it stacks up well. (I'm learning more about ADS-B than I thought I'd ever want to know ;-) ). Mac
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8233
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Name: David Freeland
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Re: ADSB

Post by 8233 »

2066 wrote: Sat May 26, 2018 5:05 pm You'll be pleased with the Stratus package -- good value & proven. Of the several practical and "affordable" options out there for our kind of flying, it stacks up well. (I'm learning more about ADS-B than I thought I'd ever want to know ;-) ). Mac
I hear you there. We already have our Super Viking ADS-B Compliant but we went with Avidyne since we also had a 430 WAAS installed. For in, we have been using a Stratus 2S and I have been very happy with the unit. The closest option I found in price was a GTX-345 that had both out and in. It was over 2k more. It had other features to tie in to Garmin gear and compatibility with Garmin Pilot. Don't need any of that so I agree the Stratus ESG seems to be the best option.

On your antenna picture, did you install a doubler to beef up the mounting point? My IA says he thinks he will need to put one in when they install mine if I use the same antenna location as your pic.

Thanks
David Freeland - CFII
1972 Bellanca Super Viking and 1946 Cessna 120
2066
Posts: 600
Joined: Tue May 01, 2018 7:00 am
Name: Mac Forbes
Location: North Carolina
Aircraft Type: '46 Cessna 140
Occupation-Interests: Retired - Current 120-140 Assoc. NC Rep.
Contact:

Re: ADSB

Post by 2066 »

RE: Antenna doubler -- yes. The previous IA didn't require one when we installed the Loran C antenna in that position a "few" years back, but since the ADS-B install manual calls for one we'll back up the GPS antenna with one (...would probably have to placard "speed limited to 300 kts unless antenna doubler installed" if we didn't? ;-)). Mac
6781
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Re: ADSB

Post by 6781 »

What is the recommended distance from the antennas. I have that same available spot where a antenna was, but I put a aviation and marine antenna on either side to balance thins out.

Thanks
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8233
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Re: ADSB

Post by 8233 »

Now that I think about it, I also have 2 com antennas on top. One is connected to the panel mounted Val Com 760 and the other has a coax run into the cockpit where it looked like a previous owner had a hand held he used with it and there is a bracket on the pilot side post at about eye level where you could hang the radio. I wonder if I could use the hole already there for that comm antenna or would that be too close to the other comm antenna? Each comm antenna is on the outer front as it relates to the skylights so #1 is NW of the Pilot side skylight and #2 is NE of the co-pilot side skylight, assuming the nose is facing north.
David Freeland - CFII
1972 Bellanca Super Viking and 1946 Cessna 120
2066
Posts: 600
Joined: Tue May 01, 2018 7:00 am
Name: Mac Forbes
Location: North Carolina
Aircraft Type: '46 Cessna 140
Occupation-Interests: Retired - Current 120-140 Assoc. NC Rep.
Contact:

Re: ADSB

Post by 2066 »

6781 wrote: Mon May 28, 2018 2:08 pm What is the recommended distance from the antennas. I have that same available spot where a antenna was, but I put a aviation and marine antenna on either side to balance thins out.

Thanks
I can't put my eyes on the reference, but the instructions I was given stated "a minimum of 2 feet" distance. Mac
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6643
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Re: ADSB

Post by 6643 »

Each antenna should be a minimum of 1/2 of the wave length of its nominal operating frequency from any other antenna, regardless of the other antenna's operating frequency. Two feet may be the correct answer for nav/com antennas. I'd have to do the math. GPS and transponder antennas operate on much shorter wave lengths, so if it's good enough for a com antenna it's good enough for GPS. Unless you still have a HF radio installed. ;)
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6643
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Re: ADSB

Post by 6643 »

Checked my notes. Nav/comm antennas should be no closer than 4 feet from any other antenna. 1000MHz+ antennas (Transponders, DME, GPS) can be as close as 6 inches, but if you put it 6" from the Comm antenna, it'll cause interference with the comm antenna.
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