Antenna selection

Hello,

I’m moving my system from M8T to F9P (already bought Ardusimple F9P) and have to select antennas.
Base station is located in town (so noisy area, lot of wifi networks etc …) but I can’t change …
For instance, I have Taoglas Active AQHA.50.A (gain = 25-28 dB) but with poor results particulary for the base station.
My question is : which antenna could you advice me particulary for the base station
(I think I could try to keep the Taoglas for the cab tractor in a first step)

  • Drotek DA910 : gain = 40 dB : 100 € + 15 € shipping + 20€ taxes
  • Ardusimple Survey : gain = 40 dB : 89 € + 18 € shipping (cheapest …)
  • ublox ANN-MB : gain = 28 dB : 50 € + 18 € shipping
  • other Tallysman, chinese Beitian …

All advices are wellcome
Best regards,
Francois

I’m using a Beitian BT-160 as my base station antenna in the middle of the city, but it’s on the roof of my building (18 meters tall, most of near buildings are smaller). The gain is also 40 db, and i’ve paid something like 60 bucks delivered.

1 Like

I do not understand. WiFi networks will not affect GPS reception. As for GPS itself, nothing terrestrial normally broadcasts on those frequencies, so there’s very little danger of interference most of the time. Pretty much any of those antennas will work fine. All you need is a clear view of the sky. What do you mean by “poor results?”

This is the one the emlid m2 uses, It is great near trees and in holes, also does not collect dirt or need a wipe constantly. Helical are great for dirty areas.

I use the above Riwala’s betian for base, its a good antenna

As Torriem said clear view of the sky is the key.

You’re more likely to experience interference for a radio sending the correction data to your rover unless you’re using ntrip.

One thing about a base station is that it works better the more satellites it can see over as much of the sky as possible. Whereas the rover might do fine next to trees (with an antenna like @PotatoFarmer showed), the base station should try to see from 20-30 degrees above the horizon unobstructed in all directions for best results. For example, if the base station is shaded by trees or buildings on one side, then it can only transmit observations for satellites its sees on the other side. If a rover happens to also be shaded, you might get many fewer satellites seen in common, which would drop it out of RTK fix mode in a hurry.

3 Likes

A Helical 1.2m off the ground on the tractors nose only loses fix once while cutting in these trees, there are also comparable trees behind the camera, Its a really great design.

I agree with @torriem the most important antenna is the base and it must see as clear a sky as possible. If you can get it up on top of a building all the better.

1 Like

Hello,
Thanks for the advices.
With “poor results” I mean :
On www.rtk2go.com, mine is FRA_62160; on caster.centipede.fr, the nearest is ARRAS (Drotek DA910), all with F9P
if I compare both :

  • 10 dB less on roughly all satellites
  • 2 or 3 less satellites
  • reception level instable with important fluctutions
  • roughly impossible to have a stable fix, if I set ARRAS as base, it becomes possible to have stable fix.

My antenna is located at the highest point of the house (chimney) with a 80 * 60 cm zinc ground plane.
The sky at 15/20 ° is fully open.
Installation is : F9P connected to Raspberry PI0W (str2str) connected by wifi to internet box (ADSL)
I’ve tried to connect the ground plane to earth of electric installation → no effect
Put a ferrite on the USB connected to F9P → no effect

This is the reason why I suspect the antenna and wonder if with a better antenna, reception levels could be better ? I suspect also that there could be reflexions (on the roof) ?
Francois

Pour la base L’antenne Ardusimple Survey a 89 euros est parfaite
pour le rover la ublox ANN-MB fait tres biens l’affaire ne négligez pas non plus le cable d’antenne celui-ci peut être la cause d’une mauvaise réception

vous ne renvoyez pas non plus les même messages
STR;ARRAS;Saint-Laurent-Blangy;RTCM 3.3; 1004(1),1005(10),1008(10),1012(1),1019(3),1020(2),1033(10),1042(3),1046(3),1077(1),1087(1),1097(1),1107(1),1127(1),1230(30);2;GLO+GAL+SBS+BDS+GPS;NONE;FRA;50.29;2.79;0;0;sNTRIP;none;N;N;11680;CENTIPEDE
STR;FRA_62160;;RTCM 3.2; 1087,1097,1127,1230;;GLO+GAL+BDS;SNIP;XXX;50.45;2.74;1;0;sNTRIP;none;B;N;0;none;
Je pense qu’il vous manque au moins 1004,1005,1008,1077

1 Like

My first suspicion would be signal loss due to long cabling.

Next i would check if the antenna impedance is in spec for the f9p, and voltage range for active antenna power.

1 Like

Hello and thank you for your help,

@torriem
I’ve double checked and my antenna (Taoglas AQHA,50,A,301111) sound compatible with f9p

  • L1 + L2
  • I supply ma < 20 mA (compatible with f9p, f9p programmed with active antenna)
  • cable is RG174 (3 m) not too bad
  • Zout = 50 Ohms, OK for f9p
  • Vin +1.8 to +5 VDC isOK
    It’s indicated not to put it on ground plane, I’ll try to remove it.
    I’ll try to evaluate exactly the sky at 20 ° from antenna

@TERVUREN
In f9p configuration, I can not activate 1004 and 1008 etc …
Only possible is 1005 (30) 1077 1087 1097 1127 and 1230 (30)
My Ntrip data are available on :
www.rtk2go.com FRA_62160
caster.centipede.fr GRENAY

I’ll try to do these test otherwise find an Ardusimple survey
Best regards,
Francois

j’ai remarqué que GRENAY etait uniquement L1 peut-être une mauvaise verion de str2str .
Vous renvoyer le signal rtcm de la f9p en passant str2str vers centipede et rtk2go alors que vous pouvez paramétrer str2str -in Format ubx et vous pouriez alors y mettres les messages que vous souhaitez une autre solution serais de connecter votre f9p a un Pi3 et d’y installer Rtkbase RTKBase: a GUI for your own Gnss Base Station Fabriquer une base RTK - Centipede RTK

1 Like

Hello,
@TERVURREN
GRENAY sur centipede n’est indiqué qu’en L1 car je n’avais que des M8T et l’administrateur avait indiqué cela dans les libellés. A présent avec le f9p je suis bien en L1 + L2 mais je n’ai pas encore effectué d’enregistrement long avec positionnement précis et mise à jour sur le site.
Merci pour vos conseils, je vais essayer de configurer le f9p en ubx rxm rawx et sfrbx et effectuer la conversion en rtcm3 avec str2str

Hello,

I’ve bought the Ardusimple Survey antenna, received yesterday.
At first quick tests, it is far much powerfull than my Taoglas one.
Reception level with f9p is far better (at least 5 to 8 dB)
I’ll install it better, do I have to put a ground plane below this antenna or could I install it without ?
Best regards
francois

for the Ardusimple Survey antenna The ground plane is unnecessary

2 Likes

Hello, I see a new antenna in AliExpress, Store Topgnss ANT105 L (about 66 dollars)

It could be a good option for use as rover or base?
Its multi frecuence l1 l2 l5 and 40db gain
Some one have cheked?
I think thats its à cheper option for use with f9p ardusimple
Thanks

1 Like

Hi
With Aliexpress double check that this Is Not à beitian rebranded
François

Yes its simillar of other antennas, but if its good Quality … it could bé usefull for ours systems.
I dont know if its best than ublox basic antenna with à ground plane, for a rover use in my tractor

It looks good to me. I already have a couple of the Beitian antennas that work well. When I need another antenna I will order one of these to try.

I have a free public ntrip base about 25 km from my fields i need one if this antennas or its good thé ublox included un the starter kit?