FLARM question

I'm trying a portable FLARM unit for first day today. Two issues on fitting it into the cockpit arose (I fly a Pegase101A).

1. There is insufficient room between panel top and canopy for both antennas to stand up straight. If I put the unit so the taller antenna is on canopy centerline, then I can get both antennas up at about 15 - 20 degrees off vertical.

Question 1 is whether this off-angle is an issue or not for xmt/rcv. Articles I've read indicate it well might be.

2. I can't see the tow plane out the front over or around the unit. The panel top is pretty close to the canopy (hence the antenna issue), so adding the height of the unit obscures the view out front terribly.

Question #2 & 3: So has anyone else (flying a Pegase) found a way around this with a portable unit so that it is still usable? Or is my panel layout/height in cockpit unique? I don't think flying with the FLARM in my lap is the answer, nor is flying tow in a constant slip.

Eric Bick

I just did a portable PF installation on my LS-3A. This link is a great place to start. Download the PDF and read through it a few times. It was provided by the manufacturer and provides details and reasoning behind the antenna installation requirements.

https://www.google.com/url?sa=t&sour...WwW6tmqWu8cCmg

You will notice in the document, the standard dipole antenna is considered to have medium performance, and as you saw they can get in the way. I went ahead and bought the remote center fed dipole antennas (be sure to pay attention to the SMA polarity) and have found that my units sensitivity to other FLARM signals is very high, and I was able to place the antennas out of sight and in a spot that has an optimal view in all directions. The only standard dipole antenna on my unit now is the ADS-B/ Transponder antenna, and with nothing else around it I have a lot of flexibility to angle it safely away from the canopy. The key there is that the PF antennas are listening for a relatively weak signal where the ADS-B antenna is looking for a very strong signal.

I hope this helps!

On Wednesday, May 14, 2014 8:55:14 PM UTC-7, Eric Bick (1DB) wrote:
I'm trying a portable FLARM unit for first day today. Two issues on fitting it into the cockpit arose (I fly a Pegase101A).

1. There is insufficient room between panel top and canopy for both antennas to stand up straight. If I put the unit so the taller antenna is on canopy centerline, then I can get both antennas up at about 15 - 20 degrees off vertical.

Question 1 is whether this off-angle is an issue or not for xmt/rcv. Articles I've read indicate it well might be.

2. I can't see the tow plane out the front over or around the unit. The panel top is pretty close to the canopy (hence the antenna issue), so adding the height of the unit obscures the view out front terribly.

Question #2 & 3: So has anyone else (flying a Pegase) found a way around this with a portable unit so that it is still usable? Or is my panel layout/height in cockpit unique? I don't think flying with the FLARM in my lap is the answer, nor is flying tow in a constant slip.

Eric Bick

The recommendation is to have the antennae as close to vertical as possible - at least not more than 15 degrees off - or the range can be affected. If I had to pick one to compromise on I'd pick the ADS-B antenna to put off-vertical because ADS-B systems and transponders put out a lot more power so you'll likely pick them up anyway. I'm also assuming you care more about picking up the Flarm traffic, but that may not be the case.

I've seen some Schleicher mounts that put the unit in front of the glare shield so you can have canopy clearance and not have it in front of your instruments. Not sure if this works for a Pegase. I think Rex Mayes at Williams Soaring developed it.

Hope that helps,

Andy
9B

When you are circling in a 45 bank, the antennae are far from vertical and seem still to work....

mj

On Thursday, May 15, 2014 1:52:15 PM UTC-7, wrote:
When you are circling in a 45 bank, the antennae are far from vertical and seem still to work....



mj

Yes but the signals is vertically polarized (vertical relative to the antenna) and your job as installer is to get the antennas as vertical as possible so that that average the signal transmission/reception is maximized.

Antenna design 101, they are linear/vertical polarized antennas, get the antennas as vertical as possible.

On Thursday, May 15, 2014 7:41:25 PM UTC-7, darrylr wrote:
On Thursday, May 15, 2014 1:52:15 PM UTC-7, wrote:

When you are circling in a 45 bank, the antennae are far from vertical and seem still to work....







mj



Yes but the signals is vertically polarized (vertical relative to the antenna) and your job as installer is to get the antennas as vertical as possible so that that average the signal transmission/reception is maximized.



Antenna design 101, they are linear/vertical polarized antennas, get the antennas as vertical as possible.

....and don't bank while you are flying!

Mike

On Thursday, May 15, 2014 9:04:22 PM UTC-7, Mike the Strike wrote:
On Thursday, May 15, 2014 7:41:25 PM UTC-7, darrylr wrote:

On Thursday, May 15, 2014 1:52:15 PM UTC-7, wrote:



When you are circling in a 45 bank, the antennae are far from vertical and seem still to work....



Now that we are starting to get AHRS into the cockpit, you can gimbal the antenna so it's always vertical.

:-)

9B

On Friday, May 16, 2014 9:24:15 AM UTC-7, wrote:
On Thursday, May 15, 2014 9:04:22 PM UTC-7, Mike the Strike wrote:

On Thursday, May 15, 2014 7:41:25 PM UTC-7, darrylr wrote:



On Thursday, May 15, 2014 1:52:15 PM UTC-7, wrote:







When you are circling in a 45 bank, the antennae are far from vertical and seem still to work....







Now that we are starting to get AHRS into the cockpit, you can gimbal the antenna so it's always vertical.



:-)



9B

I sell an antenna with a hinge and a cat. Throw the cat and watch (a cat always comes down feet first) then adjust the antenna.

Richard
www.craggyaero.com

On Friday, May 16, 2014 10:01:11 AM UTC-7, Richard wrote:
On Friday, May 16, 2014 9:24:15 AM UTC-7, wrote:

I sell an antenna with a hinge and a cat. Throw the cat and watch (a cat always comes down feet first) then adjust the antenna.



Richard

www.craggyaero.com

I tried the "hinge and cat kit" and found it to have serious flaws. The hinge was loose so the antenna flops around in turbulence. Not being a helicopter pilot, I found it difficult to stay in a tight thermal while using stick and rudder trying to keep the antenna up straight. The cat didn't help much, the one I received was freeze dried with a label clearly stating "Best Use Before Sept. 2008" Richard, you need to rotate stock.

bumper

Now that's not fair. I know for a fact that Richard turns his stock on the shelves through 90 deg every third Thursday in the month.



On Wednesday, May 14, 2014 9:55:14 PM UTC-6, Eric Bick (1DB) wrote:
I'm trying a portable FLARM unit for first day today. Two issues on fitting it into the cockpit arose (I fly a Pegase101A).



1. There is insufficient room between panel top and canopy for both antennas to stand up straight. If I put the unit so the taller antenna is on canopy centerline, then I can get both antennas up at about 15 - 20 degrees off vertical.



Question 1 is whether this off-angle is an issue or not for xmt/rcv. Articles I've read indicate it well might be.



2. I can't see the tow plane out the front over or around the unit. The panel top is pretty close to the canopy (hence the antenna issue), so adding the height of the unit obscures the view out front terribly.



Question #2 & 3: So has anyone else (flying a Pegase) found a way around this with a portable unit so that it is still usable? Or is my panel layout/height in cockpit unique? I don't think flying with the FLARM in my lap is the answer, nor is flying tow in a constant slip.



Eric Bick