How to design a weather-proof reach base station?

Reach Module / M+ / M2 Hardware integration
1

Hello,

a weather-proof reach base station needs to be placed at our office buildings roof.
The building has 4 floors. The roof is flat. Our office is at the first floor.

What radio would you recommend?
http://docs.emlid.com/reach/hardware-integration/#radio
Or a different set of radios?

Has anyone done this already?
Please post pictures.

How to access the base-reach by cable, e.g. Ethernet Network?
WiFi will be tricky, and i like to monitor the base station somehow.

Ideas and suggestions?

1 Like
2

Do you have the option to run antenna cable from to the roof to your office and place Reach inside? This is how we do it.

3

I would reccomend you to have as short cable for the GPS antenna as possible. If it is really long it will generate a lot of loss in the cable.
You could go to one of the electronics shops online and buy a ip grade enclosure. There are lots of them available for really reasonable prices.
e.g. http://no.farnell.com/schneider-electric/nsys3x4420/cabinet-s-s-400x400x200mm/dp/1853700
or http://no.farnell.com/multicomp/gtt-ac-11-n/enclosure-rf-outdoor-ip67/dp/1736441
Use cable glands for the cables and stick a din-rail PSU in the box so you could supply it with VAC.
e.g. http://no.farnell.com/xp-power/dnr10us05/din-rail-psu-10w-5v-single-o-p/dp/1858049

This should make a nice permanent base station.
You could go with some lightning protection as well, but it will make it a lot more complicated = more expensive.

For radiolink it all depends where you are located (what frequencies are use for mobile phones etc…), but 433MHz or 915MHz are normally good for long range. Use an external whip-antenna and the coverage should be acceptable.
(I use the RFD900+ in Norway, programmed to 914-915MHz. It provides quite good range.)

Cheers

4

Hi,
this is my installation, portable but also weatherproof.

Covered.jpg1096×1200 384 KB

I used a cheap Omnitracs Antenna Unit (15€ via the …bay), threw out whatever possible, placed 3s Lion-Batteries (8.5 - 12.5 Volts) down under the copper board, added a DC/DC converter to +5 Volts, connected the Reach via 3DR Radio to the mobile, 3DR under the Reach device and its copper board. The 3DR antenne is a self made Magnetic Loop Antenna for 433 MHz (small but powerfull and no groundplane neccessary, RF power output can be adjusted and connection through two walls is no problem on my side). Reach’s WiFi antenna is facing up (in the forground). The GPS antenna is placed on a round 20cm Copper plate, not really properly fixed yet, but working well. There is only one ON/OFF switch and a connector to load the Lion-Batts.
WiFi connection is done via a mobile hotspot/router between base and rover (Huawei E3572). But…WiFi to the Base is not required during ‘normal’ operation, 3DR-radio is the link to the Rover…
open.jpg2012×1836 472 KB

6 Likes
5

After looking into options, I’d like to be a bit more precise:

Set-up:
Base station:
GPS antenna -> reach -> USB to Ethernet adapter -> Ethernet cable (with POE) -> Network -> Ethernet -> PC, program.
Rover:
reach -> Bluetooth -> mobile phone -> LTE -> Internet -> dyndns -> PC, program

Question remaining:

  • Can one power the base station reach by POE (Power over Ethernet) by the Ethernet cable?
    Handling data and power with a single cable?
  • Does it need a Windows PC to run the software? Could it be a Linux “plug PC” like SheevaPlug, GuruPlug, OpenRD?
1 Like
6

That could be easily compensated by the gain in antenna LNA. We are using a 10m cable in our office as it offers convenience of constant access to the Reach, while requiring only an antenna cable running to the roof.

4 floors building should be about 12meters, so a 20m cable will do. Lets take TW3740 as an example, it has 40dB gain. U-blox recommends:

Minimum gain 5 dB (at module input)
Maximum gain 40 dB (at module input

If you use LMR400 cable on a 20 meters it will only cause about ~3.6dB of loss.

It is important with a roof install that you include appropriate lightning protection as well. So I strongly believe that having just the antenna on top is a much better option than running ethernet and power to the roof.

3 Likes
7

Is there an adapter to go from Cat5e/Cat6 (RJ45) to the antenna? I want to put the antenna on the roof and I already have Cat5e running up there from a previous Internet fixed wireless antenna.

8

@savvy0816 You can not run GNSS antenna signals through Cat5 cable.

1 Like
9

If you were crafty, you could put Reach and the antenna on the roof and:

  • use a POE adapter to send power up your Cat5 cable to the roof,
  • use another adapter to get the power from the Cat5 cable, and apply it to Reach on the DF13 connector
  • use a USB to ethernet adapter to connect your Cat5 network cable to Reach.

Attempt this at your own risk.

10

@igor.vereninov, What’s the reason?

11

This looks promising but I’m not sure I want Reach outdoors. I may keep Reach indoors.

12

@savvy0816 Cat5 cable has a different impedance and is not suited for frequencies as high as the ones carrying GNSS signals. Please only use RF cables suitable for GNSS, there should be plenty of them on eBay.

13

What about coax?

14

There are different types of coaxial cables. It has to match impedance (50Ohms), have enough frequency bandwidth and have an acceptable loss for its length. Standard TV coax won’t do.

Examples of suitable cables are: LMR-200, RG-58. Depending on the length you need.

15

What about RG59 or LMR-400? I believe it’s 75 Ohms. Is that a mismatch for GPS antennas?

16

You need a 50 Ohm cable. LMR-400 is available as 50 Ohm, as well as many other LMRs and RGs.

17

What size of RG58 suitable with reach? (In awg)