Antenna ID

[bradp]

Is this an old DME antenna behind the old Loran antenna?  My plane needs a haircut.  

-Brad. 

 

[N6758N]

2 minutes ago, bradp said:

Is this an old DME antenna behind the old Loran antenna?  My plane needs a haircut.  

-Brad. 

 

Nope, thats a Comm antenna. 

[bradp]

So the forward antenna I thought was a Loran antenna is a com antenna ... and the Short and Stubby antenna aft is...?

[jaylw314]

DME antenna should look the same as a transponder--either stick-and-ball or a blade-type antenna about 3 inches deep.  That one doesn't look like either.  And yes, the forward antenna looks like a COM antenna

Edited September 6, 2017 by jaylw314

[tony]

It looks like a brand new ADSB-in  antenna to me.

[N201MKTurbo]

It looks like a Comant Antenna Loran C PN CI-422SP-2

Can't place the little guy.

[jaylw314]

42 minutes ago, tony said:

It looks like a brand new ADSB-in  antenna to me.

That sounds like a better guess.  It could also be something non-standard, like a remote antenna for a hand-held radio or cellphone antenna?

[jetdriven]

THE comant ci-122 and the Loran antenna they made look identical. The data plate will say. 

Edited September 6, 2017 by jetdriven

[OR75]

just realized you were talking about he antenna BEHIND the Loran antenna

 

Edited September 6, 2017 by OR75

[tigers2007]

Can you easily unscrew it? SMA jack? I agree with Tony that it looks like an ADS-B receiver antenna.


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[peevee]

That big one is a loran antenna? We still have one of those. Bet it's good for a knot or two.

[bradp]

I'm thinking that the little one in the back I can replace with an ADS-B mounted antenna and the one in the front I can replace with a CI-122 or similar to get com 1/2 on top/bottom or vice versa.   

Neither is connected to anything right now.  

[neilpilot]

If you carry a backup handheld com, consider running the spare com to a panel or under-panel mounted jack to use as an external antennae 

[EricJ]

2 hours ago, bradp said:

I'm thinking that the little one in the back I can replace with an ADS-B mounted antenna and the one in the front I can replace with a CI-122 or similar to get com 1/2 on top/bottom or vice versa.   

Neither is connected to anything right now.  

In that case, try to see if the little one has any markings on the hidden portions of it to get a model number or part number or something.   You really want to know what band it's tuned for before hooking it up to something.   Given the various ways to build antennas, you can't really tell by looking except in a very general sense.   If you want it to do something specific (like comm or ADS-B or whatever), it is generally worthwhile to verify that it'll have a decent response at those frequencies.

FWIW, DME antennas are reasonably well matched to ADS-B frequencies enough that I would expect a DME antenna to have a good chance of working for ADS-B in.   This is something I have in mind to try in the future (there's a DME in my airplane but it's inop and I don't see a reason to fix it).

Thirty-year wireless comm engineer here, but don't trust anything I say.

[jaylw314]

42 minutes ago, EricJ said:

In that case, try to see if the little one has any markings on the hidden portions of it to get a model number or part number or something.   You really want to know what band it's tuned for before hooking it up to something.   Given the various ways to build antennas, you can't really tell by looking except in a very general sense.   If you want it to do something specific (like comm or ADS-B or whatever), it is generally worthwhile to verify that it'll have a decent response at those frequencies.

FWIW, DME antennas are reasonably well matched to ADS-B frequencies enough that I would expect a DME antenna to have a good chance of working for ADS-B in.   This is something I have in mind to try in the future (there's a DME in my airplane but it's inop and I don't see a reason to fix it).

Thirty-year wireless comm engineer here, but don't trust anything I say.

ADS-B and DME frequencies are pretty much the same, and the antennas should be compatible, but I assume some ADS-B installs (like my KT-74-G530W) have an antenna requirement specified in the STC (only blade-type antenna).

[EricJ]

8 minutes ago, jaylw314 said:

ADS-B and DME frequencies are pretty much the same, and the antennas should be compatible, but I assume some ADS-B installs (like my KT-74-G530W) have an antenna requirement specified in the STC (only blade-type antenna).

Yes, but if you have a stratux or something like that it could be worthwhile to use an existing external antenna.   That's my plan, anyway.

[bradp]

6 minutes ago, jaylw314 said:

ADS-B and DME frequencies are pretty much the same, and the antennas should be compatible, but I assume some ADS-B installs (like my KT-74-G530W) have an antenna requirement specified in the STC (only blade-type antenna).

One of the reasons i decided to go with a GTX-330 ES was that it requires a TSOd antenna in the STC, but specifically doesn't call out a particular style (blade) or model, and it uses a choice of airspeed / squat switch or can use a GPS signal in with software processing to determine air-ground rather than needing to open up the pitot / static system. Seemed overall less invasive despite needing to repin the connectors. 

[N201MKTurbo]

51 minutes ago, bradp said:

One of the reasons i decided to go with a GTX-330 ES was that it requires a TSOd antenna in the STC, but specifically doesn't call out a particular style (blade) or model, and it uses a choice of airspeed / squat switch or can use a GPS signal in with software processing to determine air-ground rather than needing to open up the pitot / static system. Seemed overall less invasive despite needing to repin the connectors. 

I wired the WOW (Weight On Wheels) signal from my Avidyne IFD550 to the transponder for air/ground switching. It was the easiest and cleanest solution. It works perfect except for one little issue. The Avidyne takes a long time to boot up. The transponder boots up much faster. The transponder will squawk that its airborne until the Avidyne comes to life.

Probably not a big issue. I know I can change the polarity of the signal in the transponder. I'm not sure I can change it in the IFD550. Probably best to leave it the way it is so if the IDF550 goes south the transponder will still squawk airborne.   

[tony]

So here's the point I was trying to make:  AC 120-76B  on page 4 paragraph d says:

Portable COTS-based computers, considered to be PEDs with no FAA design, production, or installation approval for the device and its internal components. Class 2 EFBs are typically mounted. They must be capable of being easily removed from or attached to their mounts by flightcrew personnel. Class 2 EFBs can be temporarily connected to an existing aircraft power supply for battery recharging. They may connect to aircraft power, data ports (wired or wireless), or installed antennas, provided those connections are installed in accordance with AC 20-173. (Portable Class 2 EFB components are not considered to be part of aircraft type design; i.e., not in the aircraft TC or STC.)

Therefore it should be perfectly legal to connect your PED to an existing antenna that is currently not in use.  Since there are a lot of old DME antenna's on aircraft, and the frequency band for ADSB-in is the same as the old DME signal, I would suggest leaving the DME antenna there and someday use it with your stratus.