Antennas for Reach M2

Emlid has this one https://store.emlid.com/product/multi-band-gnss-antenna/ ,I am using it with very good results.Is there any reason you would not use it?
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I have no doubt that the emlid antenna will work well, but I was looking for something that would go in the original housing that the old L1 novatel gps Antenna went.

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Maybe this will fit ?

I know what isn’t working. I tried a Trimble AG25 L1/L2/L5 no satellites. I was hopeful as I have a spare handy.

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That looks like it would fit, I will go and check the housing. Do you have a link to a place where I could buy this? Who makes it?

https://www.swiftnav.com/store/accessories/gnss-antenna-pack

Actually, someone else told me that a Trimble AG25 does work. I am wondering if the cable I purchased, Reach M2/M+ TNC antenna adapter cable 2m, might have a problem. I will be checking with a multimeter this evening.

Hey there,

When choosing the antenna for M2, I highly recommend checking its specs before connecting the antenna. Reach M2 only handles antennas that meet the following requirements:

  • Antenna output current no more than 100 mA
  • Antenna DC bias is 3.3 V

More info on Reach M2 electrical specs can be found in our docs.

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Hi Tatiana

I have additional questions. Multi-band GNSS antenna (https://store.emlid.com/product/multi-band-gnss-antenna/) phase centers’ offsets for L1 = 0.032m; L2 = 0.037 m. the Value L1 = 0.032m ; L2 = are 0.037 m zaplikowane to software internal Reach M2? How to introduce given L1 and L2 for the different aerial? Are there with the regard of L1 and L2 heights in NMEA?

Hi Pawel,

The L1 or L2 offset could be added at the post-processing stage in RTKPost by using the following setting. The phase offset should be inputted into the U field. The 5 mm difference between the L1 and L2 in most cases won’t result in a significant difference in Z coordinate.


The phase offsets are not included in NMEA messages, however, this data could be added to the position in the NMEA message afterward too.

Hi Artem

He thanks for the answer.
Explain additionally. Coordinate “Z” from results from the data in NMEA:

  1. L1 ?
  2. L2 ?
  3. average from given L1 and L2 ?

On the example my aerial L1= 0,0516 m; L2 = 0,0556. Height of the stick 2,00 m. Coordinate Z on the basis of the announcement NMEA Z = 100,00 m.
What is he the correct height of the mierzonego point?

  1. H = 100,00 - 0,0516 - 2,00
  2. H = 100,00 - 0,0556 - 2,00
  3. H = 100,00 - ((0,0516 + 0,0556)/ 2) - 2,00

Hi Pawel,

Thank you for your patience.

The phase offset and antenna height are not included in the NMEA message. So in case you want to include these values, you will need to substitute both of them from the height declared in the NMEA string.

Hi there,
I am looking also for a survey antenna for the M2.
Do you think Harxon GPS500 is the best choice? What about GPS1000?
The specs of the GPS500 doesn’t list GALILEO support.
https://www.orbitica.com/harxon/harxon-survey-antenna.htm#GPS500
I see these antennas listed for about 150$ in Aliexpress.
Is the Swiftnav antenna the same as GPS500 for sure?

1599049000961_SwiftNav Mini Survey Antenna GPS500 Specifications v1.2.pdf (1006.3 KB)

If your just using it for pass to pass ag guidance, the small tallysman is accurate enough for cm performance. It needs vibration damping on the tractor side.

Post processing is great but it does not plant crops particularly well. The m2 really handles well even at 5hz, i am impressed by its guidance performance.

Have you integrated your m2 to the outback hemisphere steering system? If so please tell the details.

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Hi Artem

Altitude is passed from in the announcement NMEA the observation:

  1. L1?
  2. L2?
  3. Enumerated from average observations L1 and L2?

On the example my aerial L1= 0,0516 m; L2 = 0,0556. Height of the stick 2,00 m.

  1. H = 88,684 - 0,0516 - 2,00 = 86,6324 ?
  2. H = 88,684 - 0,0556 - 2,00 = 86,6284 ?
  3. H = 88,684 - ((0,0516 + 0,0556) / 2) -2,00 = 86,6304?

Which calculation is correct?

Hi Pawel,

Thanks for your patience.

I’d considered taking the formula number three here as a basis. The height string in the NMEA message is referenced from the ARP and neither both phase offsets, nor the survey pole height are not included in it.

Also, there is one more point to consider: the NMEA message includes the geoid separation height, which comes straight after the number you’ve highlighted on your screenshot. You can consider summing it up to your measurements depending on your use-case.

Hi Artem

He thanks for the professional answer.

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A post was merged into an existing topic: Geodetic Antenna for Reach M2