Which GPS antennas work well....

[Mattpgreen]

All.. I received the active gps coded AGGO55 ... This morning .... After setting it up ... And it looking all professional ... I couldn't get a 3D fix ... So back on with the Dipole and 24 sec later ... Solid blue light ... Mmm dipole it is or now

[Max]

[Kisssys]

If it's not an active antenna it is quite commonly shorted. You basically had the 3v3 volt line shorted to ground through the 10 ohm resistor and inductor. Gps is probably ok not sure about the resistor and inductor.

[JussiH]

I can confirm that the FXP.611 cloud antenna will not work with the M4 V2, unless a modification is made to the Ublox antenna power supply.

V2 has a M8Q GPS module mounted. This was done by mistake, and to make the V2 boards work with active/powered antennas, a modification had to be done. It involves adding a Resistor and an Inductor to the antenna circuit:

Fix01.JPG (105.48 KiB) Viewed 17014 times

However, the M8Q does not support antenna short circuit detection like the M8W module the boards was designed for.

This means, that to use passive antennas like the FXP.611 that appears to short the element to ground, you will have to remove the Inductor and Resistor to have the antenna feed unpowered.

I did some preliminary tests with these FXP.611 antennas and I gotta say I am less than impressed with them so far. I can barely get them to get a fix on the ground.

On the same board in a ground test, The dipole fixed in 30-40 seconds and aquired a Hacc ~ 1m in minutes, while the FXP.611 took several minutes to fix and then never got under a a Hacc of 2.5.

But this was one single, non-comparative test, so its not conclusive in any way....But right now, I am not betting on the FXP.611 and I wouldnt remove the Resistor and inductor on a V2 to be able to use it.

You can use the FXP.611 on the V1 boards. A normal Dipole works on V1 and V2 boards.

I am gearing up to make better and more comparable antenna tests in the near future. But right now I recommend using the Dipole or a 10mm Ceramic on on pocket crafts.

[Max]

Thanks Jussi. I was wondering why Larry was having success with the passive cloud antenna on the M4 v1s he has. Closed-loop detection... makes sense. I might try it on a v1 then, since that is safe.

Based on your experiences, and assuming my resistor and inductor (and I have a cap too! ) survived the experiment, I won't be removing them quite yet. The "cloud" sounds cool on paper, too bad if it doesn't perform for our needs.

-Max

[DUKE40]

Hi Jussi,

thanks for this clear explanation. I hope too my test with the antenna has not left any damage to my board.
This would be very bad, especially in the light, that Larry wrote this antenna would be OK and I trusted it.
Who could have known that it works for v21 board but not for v2 boards.
I will try to see if I get a 3D Fix with the new antenna I have today as the weather is windy but no rain till now.

[JussiH]

Based on my tests so far, connecting a FXP.611 to a M4 V2 board with the Resistor/inductor modification will not do any damage

[Max]

The good news is that the antenna is probably still OK.

Hooked up known-good 35mm active ceramic patch to the affected v2 and got a quick 3D lock indoors through a window, ~1.4m hAcc, ~1.8m vAcc after a few minutes. So that's some more good news. Hopefully yours is the same, Duke.

-Max

[DUKE40]

Hi,

just tested in my garden, not the best place, but for a quick test enough.
I got a 3D fix within one minute with the following antenna:
Taoglas Limited
AGGP.25F.07.0060A

hAcc was around 2 meters, quite a lot, but I assume that this was due to the suboptimal environment and will do much better in a real open field.
I will see when I get the time to take everything on my flying field to check the hAcc there. The vAcc was also quite unprecise, but this might also have been caused by the environment.

At least it seems no damage from the use of the FXP.611 remain.

[bn999]

Never had much luck with the cloud antenna.