Experience: Which antenna for HMS and CMT2300A?

[MichaMEG]

Because the reception quality is very poor with the throw antennas (https://shop.allianceapps.io/products/allianceapps-opendtu-fusion?pr_prod_strat=e5_desc&pr_rec_id=75a10c2e4&pr_rec_pid=8454540132680&pr_ref_pid=8439160406344&pr_seq=uniform). What can you recommend here?

I ordered this one, but it hasn't arrived yet:
https://www.amazon.de/gp/aw/d/B0978Q7N7C?ref=ppx_pt2_mob_b_prod_image

After changing the position of the inverter, it is now slightly better (HMS-400-1T):
Gesendete Anfragen 698
Empfang Erfolgreich 632 91 %
Empfang Fehler: Nichts empfangen 54 8 %
Empfang Fehler: Teilweise empfangen 0 0 %
Empfang Fehler: Beschädigt empfangen 12 2 %
Gesendete Fragment Wiederanforderungen 14

Before that, only max 40 per cent of parcels arrive.

Thanks

Michael

[MichaMEG]

The older Hoymiles HM-600 via NRF24 do not seem to have any problems.

[stefan123t]

HM inverters use nRF24L01+ with a common base frequency in the WIFI/Bluetooth 2.4GHz range.
Whereas HMS/HMT inverters use CMT2300A for communicating in the 868MHz frequency band in EU and 915MHz in US/NA regions.
Please take care to use an antenna adopted for the intended RF frequency range.

Maybe your “throw” antenna for the CMT2300A got mixed up ? You may ask the seller for a proper replacement as I have not heard of many complaints regarding the foil antennas the OpenDTU Fusion boards come delivered with.

[MichaMEG]

Thank you for the detailed answer.
I realise that the antennas must match the frequency.
How can I tell the difference between the “throw” antenna, different lengths?