Reach RTK | alternative GNSS combinations for time mark logging

Even if it does not look as beautiful as I would like it to the data provided 99.3 % fix (with @wsurvey more conservative settings than the standard Emlid ones (e.g. no fix-and-hold)) for a mission with 2200 images. I have now added some extra lead apron around all receivers and electronics (I think I have added 50g of additional rf shielding. The copter flies about 30 min. with small props, so I decided to trade in better SNR values for flight time…). I will try tomorrow if I can improve the result.

For the on ground survey the results where fantastic (after I have adapted all settings within RTKconv and RTKpost/the cmd line tools), I’m quite happy with you’re recommendations @wsurvey!

I would be still very interested in your feedback, what do you recommend?

Don’t you offer the cables as well?

Teokit cable is MCX to MCX and 15 cm length only.

Ok, can I have a special price for the cable / do you ship to Germany? Than I would like to buy an antenna and a cable and compare. OMG, the antenna is not MCX, I see…

Please write me which cable do you want and do you need antenna?
Tomorrow I will see what can I do for you…

I see a few issues with the near-horizontal lever-arm extending out, first one being vibration, which could cause the excessive amount of cycle-slips you have.
Second being you need quite a bit of cable to get out there. The shorter the cable the better.
If it was platform, I would rather move the antenna in on centerpieces on a vertical pole (like a carbon pole of a decent OD).
And probably even more likely, look into helical antennas instead. Much smaller footprint.

us DJI pilots would love that flight time.

owing to @VanavaraDigital endorsement i have purchased the BT560 L1 spiral antenna and this cable: https://www.unmannedtechshop.co.uk/product/reach-mcx-male-to-sma-female-antenna-adapter-cable-50cm/
When I get results I will let you know how the spiral performs compared to the patch antenna. Cycle slips aren’t much of a problem after my vibration isolation efforts, but I’m looking for better SNR values as i think BeiDou and Galileo reception could be stronger:

The best way to use BT-560D for L1 Reach M+.

Thank you for the input! Now I understand why I had more and more problems with cycle slips.

When we talk about vibration we have to consider that I’m flying in strong wind. More wind and gusts cause more vibration. I think it is hard to compare flights with different amounts of wind.

I guess you fly in Danmark with a lot of wind too, would you share images of youre setup und youre SNR results?

A part of my cycle slips are connected to a vibrating motor (DOA) which I have to replace.

Do you recommend to shorten the antenna cable? Which tools and adpters do you use, can you recommend some?

I’m very interested in the results! And thank you very much for the SNR data visualization, its always good to have a reference!

If you have good results with the antenna I will buy one from @VanavaraDigital/Konstantin.

Hey @tobias-dahms ,

Results of the spiral antenna are good, as can be seen on the following plot. UAV was on the ground, among trees, until 00:35. From there you can see it clear right up. BeiDou Geo satellites (C01-C04) are now tracked properly and are useful for processing, whereas before they were a cycle-slip mess. There is still directionality evident in the SNR, but is not enough to matter.

Thank you @VanavaraDigital for your antenna recommendation. I have better tracking and saved about 15g weight. I appreciate your participation in the forum.

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Hi, you are welcome)

Yesterday I made L1/L2 tests.
Results are there: AShot - new way for integration of Reach M+ to DJI Phantom 4 adv | pro

Great, thank you very much @wsurvey! I will try it too! Can you send me a picture of how you mounted the antenna? Where did you buy your BT-560D?

@VanavaraDigital Konstantin, I would like to buy two (or is there a special discount for 3 or 4?) of your or the BT-560D antennas. What would be the delivery time?

I think I found a suitable cable:
https://www.minipc.de/de/catalog/il/2613?gclid=EAIaIQobChMIiIOo9e275QIViK3tCh0J7gBvEAQYBCABEgJBPfD_BwE

Tobias,

As for antenna shopping, I just go to ali express and search for ‘bt-560d’, and buy the cheapest one. That’s how I’ll get my next one. I will convert the second unit as soon as I can based on my test.

As for mounting, I bought some 25x25x1.5mm L-shape aluminium extrusion, cut a small piece, drilled a 6.5mm hole for the antenna, drilled 2x2mm holes for mounting to the timber mast, and strengthened the mount with 2-part epoxy.

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That one looks really like the Emlids L1/L2 antenna for the M2 unit…
Whats the idea around the antenna shape?

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It also looks like this waterproof, airtight, durable, smellproof stashjar:
stash_jar

but I digress…

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Close but no sigar for you :wink::sweat_smile:

Its a half hollow cylindrical antenna.
Edit: That pdf was old…

Edit 2: In depth from Ublox https://www.u-blox.com/sites/default/files/products/documents/GNSS-Antennas_AppNote_(UBX-15030289).pdf

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How many SNR do you think you could get from a backfire resonant quadrifilar helix DIY coathanger antenna?

Very cheap to build, but you might spend too many hours of labour making and testing different tunings.

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I would go for a 3d printed version. I guess someone already made it… .

https://www.researchgate.net/publication/275828209_The_Basics_of_Quadrifilar_Helix_Antennas/figures?lo=1