PowerFlarm Range Analysis for "WX" - 15M Nats Yreka 2014

Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

On Tuesday, March 24, 2015 at 12:32:03 AM UTC-7, waremark wrote:
Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

Well, over my last two seasons of flying nobody seemed to "sneak" up on me with the flarm signal. However, it is obvious when following others that when you get behind and slightly below them in a glider with a carbon fuselage, that the signal drops out pretty quickly... say in less than one mile. One possible solution would be to put a second antenna (receive only is all that's available) on the bottom. That way, someone else couldn't sneak up on me. Does anyone else out there have experience with a second flarm antenna?

Walt Rogers

Le mardi 24 mars 2015 21:23:51 UTC+1, WaltWX a écrit*:
On Tuesday, March 24, 2015 at 12:32:03 AM UTC-7, waremark wrote:
Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

Well, over my last two seasons of flying nobody seemed to "sneak" up on me with the flarm signal. However, it is obvious when following others that when you get behind and slightly below them in a glider with a carbon fuselage, that the signal drops out pretty quickly... say in less than one mile. One possible solution would be to put a second antenna (receive only is all that's available) on the bottom. That way, someone else couldn't sneak up on me. Does anyone else out there have experience with a second flarm antenna?

Walt Rogers

I have an antenna splitter installed. First antenna is a stripe antenna in the canopy (laterally & slightly behind my head), second antenna is the standard lambda/4 "toothpick" by the gear door. The Ventus cM is all carbon, and I have 5 km reception all around with a Flarm 5.

....And you don't mind the approximately 50% loss (3.5 dB) in signal
strength due to the splitter? I don't want to figure out how that
affects detection range.

snip

I have an antenna splitter installed. First antenna is a stripe antenna in the canopy (laterally & slightly behind my head), second antenna is the standard lambda/4 "toothpick" by the gear door. The Ventus cM is all carbon, and I have 5 km reception all around with a Flarm 5.

--
Dan Marotta

On Wednesday, March 25, 2015 at 7:13:59 AM UTC-7, Dan Marotta wrote:
...And you don't mind the approximately 50% loss (3.5 dB) in signal


It doesn't work that way Dan. With two antennas gathering energy from the same surroundings, the effect is primarily an alteration of pattern.

The greater concern might be polarization. PowerFlarm is a vertical polarization system. I'm not exactly sure what TW means by "stripe antenna in the canopy (laterally & slightly behind my head)". That doesn't sound vertical polarized; hopefully I'm just not visualizing that correctly.

You're right, Steve! I was thinking of 1 antenna feeding two receivers.

Dan

On 3/25/2015 9:55 AM, Steve Koerner wrote:
On Wednesday, March 25, 2015 at 7:13:59 AM UTC-7, Dan Marotta wrote:
...And you don't mind the approximately 50% loss (3.5 dB) in signal

It doesn't work that way Dan. With two antennas gathering energy from the same surroundings, the effect is primarily an alteration of pattern.

The greater concern might be polarization. PowerFlarm is a vertical polarization system. I'm not exactly sure what TW means by "stripe antenna in the canopy (laterally & slightly behind my head)". That doesn't sound vertical polarized; hopefully I'm just not visualizing that correctly.

--
Dan Marotta

On Wednesday, March 25, 2015 at 6:24:34 AM UTC-7, Tango Whisky wrote:
Le mardi 24 mars 2015 21:23:51 UTC+1, WaltWX a écrit*:
On Tuesday, March 24, 2015 at 12:32:03 AM UTC-7, waremark wrote:
Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

Well, over my last two seasons of flying nobody seemed to "sneak" up on me with the flarm signal. However, it is obvious when following others that when you get behind and slightly below them in a glider with a carbon fuselage, that the signal drops out pretty quickly... say in less than one mile. One possible solution would be to put a second antenna (receive only is all that's available) on the bottom. That way, someone else couldn't sneak up on me. Does anyone else out there have experience with a second flarm antenna?

Walt Rogers

I have an antenna splitter installed. First antenna is a stripe antenna in the canopy (laterally & slightly behind my head), second antenna is the standard lambda/4 "toothpick" by the gear door. The Ventus cM is all carbon, and I have 5 km reception all around with a Flarm 5.

As pointed out an antenna splitter is not what you should be using. That will lead to signal reinforcement or cancellation depending on the relative phase of the signals from each antenna. It might help you when one receiver antenna is significantly blocked from receiving the transmitter signal but can cause serious reception problems when a transmitter signal is visible to both antenna. This is just not the way to to this. The proper way is to utilize a device designed for two antennas, like with the PowerFLARM, which essentially contains two separate receiver front ends, one for each antenna.. And various FLARM documentation specifically says don't use an antenna splitter... for this exact reason.

Le jeudi 26 mars 2015 03:11:38 UTC+1, Darryl Ramm a écrit*:
On Wednesday, March 25, 2015 at 6:24:34 AM UTC-7, Tango Whisky wrote:
Le mardi 24 mars 2015 21:23:51 UTC+1, WaltWX a écrit*:
On Tuesday, March 24, 2015 at 12:32:03 AM UTC-7, waremark wrote:
Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

Well, over my last two seasons of flying nobody seemed to "sneak" up on me with the flarm signal. However, it is obvious when following others that when you get behind and slightly below them in a glider with a carbon fuselage, that the signal drops out pretty quickly... say in less than one mile. One possible solution would be to put a second antenna (receive only is all that's available) on the bottom. That way, someone else couldn't sneak up on me. Does anyone else out there have experience with a second flarm antenna?

Walt Rogers

I have an antenna splitter installed. First antenna is a stripe antenna in the canopy (laterally & slightly behind my head), second antenna is the standard lambda/4 "toothpick" by the gear door. The Ventus cM is all carbon, and I have 5 km reception all around with a Flarm 5.

As pointed out an antenna splitter is not what you should be using. That will lead to signal reinforcement or cancellation depending on the relative phase of the signals from each antenna. It might help you when one receiver antenna is significantly blocked from receiving the transmitter signal but can cause serious reception problems when a transmitter signal is visible to both antenna. This is just not the way to to this. The proper way is to utilize a device designed for two antennas, like with the PowerFLARM, which essentially contains two separate receiver front ends, one for each antenna. And various FLARM documentation specifically says don't use an antenna splitter... for this exact reason.

The splitter I have is from Bernd Dolba (www.dolba.de - German only, sorry for that...)and was designed for Flarm's. Both antennas are polarized 30-45° from vertical.
I don't care about limiting contact range to 5 km, but I care a lot about not having blind spots. With an all-carbon fuselage, you can't avoid blind spots if you're just using one antenna.

Cheers
Bert

On Thursday, March 26, 2015 at 4:23:36 AM UTC-7, Tango Whisky wrote:
Le jeudi 26 mars 2015 03:11:38 UTC+1, Darryl Ramm a écrit*:
On Wednesday, March 25, 2015 at 6:24:34 AM UTC-7, Tango Whisky wrote:
Le mardi 24 mars 2015 21:23:51 UTC+1, WaltWX a écrit*:
On Tuesday, March 24, 2015 at 12:32:03 AM UTC-7, waremark wrote:
Your performance is way better than my Euro Flarm fitted inside the LX 9000.

My problem with the range analysis tool is that it only tells you where you did pick up gliders. It does not tell you about the Flarm equipped gliders which you did not pick up. Did you never get contacts (or gliders) 'suddenly' appear closer than say 2k?

Mark Burton

Well, over my last two seasons of flying nobody seemed to "sneak" up on me with the flarm signal. However, it is obvious when following others that when you get behind and slightly below them in a glider with a carbon fuselage, that the signal drops out pretty quickly... say in less than one mile. One possible solution would be to put a second antenna (receive only is all that's available) on the bottom. That way, someone else couldn't sneak up on me. Does anyone else out there have experience with a second flarm antenna?

Walt Rogers

I have an antenna splitter installed. First antenna is a stripe antenna in the canopy (laterally & slightly behind my head), second antenna is the standard lambda/4 "toothpick" by the gear door. The Ventus cM is all carbon, and I have 5 km reception all around with a Flarm 5.

As pointed out an antenna splitter is not what you should be using. That will lead to signal reinforcement or cancellation depending on the relative phase of the signals from each antenna. It might help you when one receiver antenna is significantly blocked from receiving the transmitter signal but can cause serious reception problems when a transmitter signal is visible to both antenna. This is just not the way to to this. The proper way is to utilize a device designed for two antennas, like with the PowerFLARM, which essentially contains two separate receiver front ends, one for each antenna. And various FLARM documentation specifically says don't use an antenna splitter... for this exact reason.

The splitter I have is from Bernd Dolba (www.dolba.de - German only, sorry for that...)and was designed for Flarm's. Both antennas are polarized 30-45° from vertical.
I don't care about limiting contact range to 5 km, but I care a lot about not having blind spots. With an all-carbon fuselage, you can't avoid blind spots if you're just using one antenna.

Cheers
Bert

OK, thanks for that pointer. Looks like they know what that are doing and hopefully try to avoid purchasers doing silly things with dual antennas.

Darryl

I contacted Walt, on private email, to praise him for his excellent range.
It appeared to be significant better than mine, with similar make, model and antenna placement.
My different files were showing significant irregularities, side lobes, skewed to one side, etc.
While I dug a bit deeper into this, I noticed in the range analysis image that Walt published above, shows a huge number of contact points. Like 11000 points in his biggest file.
When reviewed my analysis output, I only noticed about 400 points on several 400k flights.
Now, I fly in the "big air" of the Sierras, where contacts with other Flarm equipped gliders can be far and between.
And Walt mentioned that his files were taken during a contest, which, I guess, means a lot of close proximity flying.
So, I decided to concatenate a few of my long IGC file and uploaded the larger file (2000 points) to the analysis tool. Now my pattern look much better, much more homogeneous with good range.
Conclusion: Be careful about drawing conclusions from your Range Analysis output when you only have few contact point ( 500 points).
If in doubt, concatenate some files into a big file and run this big file through the analysis to see if that yield a better result.
Also notice that the analysis reports maximum ranges in the 30-40 km range. Don't know if that is real and if it includes ADS-B pings. If it is Flarm range, that's very good !
3U