Rak 3112 and MHF4

WisBlock
1

Hi RAK community,

I’m building rugged LoRa nodes (car-mounted, solar-powered, off-grid) and recently switched to the RAK 3112 for its features. However, the MHF4 (IPEX4) connectors are a major pain point they pop off with the slightest tension, even with careful strain relief.

For context:

• All my current production nodes use the RAK19007 + RAK4631 combo with MHF1 connectors.

• I use RG178 coax (which works perfectly with MHF1 but is too thick for reliable MHF4 mating).

• These nodes survive vibration, weather, and rough handling but MHF4 fails instantly.

I found this 3D-printable MHF4 pigtail bracket on Printables and am testing it as a temporary fix:

:link: RAK IPEX Pigtail Bracket

Questions for the community / RAK team:

  1. Are there official strain relief or locking MHF4 pigtails recommended for high-vibration use?

  2. Any experience using thinner coax (e.g., 0.81mm) with MHF4 in rugged environments?

Would love to hear from others doing mobile/solar deployments.

Thanks!

2

Welcome to RAK forum @SolidLink ,

We understand your feedback on MHF4 connector. It was a tradeoff we had to make to maintain the small form factor. MHF4 has lesser retention force compared to MHF1 due to mechanical limitations (it is just small).

Great work on the DIY bracket. Other option is to put adhesives to maintain it in place.

Also compared to MHF1, MHF4 are not generally designed for multiple removal. Once the antenna connector is plugged-in, it is recommended to keep the connection unless for necessary repairs or adjustment. This is something to keep in mind while doing prototyping.