Regarding the use of HC771 Tallysman Single band helical antenna in Reach M+ .

Hi Users,

I am recently using Reach M+ module with TW4721 Single Band GNSS Antenna which is requiring a ground plane. I have been using(under test condition) it in drone as a rover, but every time I am getting low SNR (Signal to noise ratio not greater than 40).

So , I want to use HC771 Tallysman Single band helical antenna in Reach M+ which does not require any ground plane as per manufacturer specifications.

So my question is can I use it with Reach M+ Module without any problem? If not , please give me a suggestion to use any other helical antenna with with Reach M+ module.

Thank you .

Tallysman tw4721Tallysman HC771

HC771 will work, for M+ only.

The Dual band HC871 should work as well, plus it will work with both M+/M2.

Buying Tallysman antennas are worth a few bucks and are very compact and light, have had zero issues with the HC871’s included with the M2. Emlid has the beast deal at $200USD I can find for the genuine premium antenna.

If you are on a budget, and want a cheaper option here is some others from Aliexpress.
Ive tried the HX-609 (7). Its a little large for small drones but works very well. This vendor has other options and I have had good relation with the sales team on other purchases.

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Hi @shashibhusan1995,

Welcome to the forum!

Patch antennas are pretty sensitive to external conditions, so it’s not only required to place them on the ground plane but to make sure there are no sources of RF noise. You also need to isolate Reach M+ from the potential interference. The correct arrangement of the drone components will ensure you have good GNSS signal reception.

This is a helical antenna. Even though it’s protected from interference from the back side of the antenna because of its shape, we still recommend placing them on the ground plane. It can improve observation quality significantly. In some cases, it might be reasonable to mount the helical antenna on a ground plane for safety redundancy.

We haven’t tested this antenna ourselves, but I don’t see any obvious reasons why it won’t work.