BayMesh 3 Bandpass Filter

BayMesh | Part: BM3

Bandpass cavity filter with ~3.5MHz bandpass and two SMA connectors.

Comments from the Austin Mesh Community

If you need a serious filter, this is the choice. Hand tuned/checked and sent with a spec sheet for your specific serial number. Can be retuned as needed but requires technical knowledge and a VNA. The Baymesh 3 is one of 3 filters (BM4 and BM5 are the others) made by Nullrouten of BayMesh.

Specs

Brand

BayMesh

Part Number

BM3

Filter Type

Bandpass

Connectors

2x SMA Female

Loss at Meshtastic (906.875 MHz)

7.56 dB

Loss at MeshCore (910.525 MHz)

1.42 dB

Return Loss at Meshtastic

3.5 dB

Return Loss at MeshCore

20.2 dB

3 dB Passband

907.5-913.9 MHz (6.4 MHz)

Dimensions

107 x 60 x 41 mm

Test Results

This page collects 2-port VNA measurements of 2 units of the BayMesh 3 Bandpass Filter, measured firsthand by the mesh community (KG5HZC). Every sweep is charted below and downloadable as a Touchstone (.s2p) file. Measured 3 dB passband is 907.5-913.9 MHz (6.4 MHz wide).

S/N 20260326012

At Mesh Operating Frequencies

Meshtastic (906.875 MHz)

Loss: 7.56 dB

Return loss: 3.5 dB

MeshCore (910.525 MHz)

Loss: 1.42 dB

Return loss: 20.2 dB

3 dB passband: 907.5-913.9 MHz (6.4 MHz wide), minimum loss 1.36 dB at 909.8 MHz.

Out-of-Band Rejection

433 MHz (70cm ham / ISM)47.2 dB

700 MHz (LTE 700)49.4 dB

824 MHz (Cellular uplink)46.7 dB

894 MHz (Cellular downlink)48.5 dB

930 MHz (Pagers)50.8 dB

960 MHz (Fixed links)49.9 dB

1090 MHz (ADS-B)48.5 dB

Notes from test

No notes available

Tested By

Tommy Ekstrand, KG5HZC on 2026-07-11

Sample 20260326012

Download .s2p (902-928 MHz, 101 points)Download .s2p (430-1500 MHz, 101 points)

S/N 20260514001

At Mesh Operating Frequencies

Meshtastic (906.875 MHz)

Loss: 8.01 dB

Return loss: 4.1 dB

MeshCore (910.525 MHz)

Loss: 1.66 dB

Return loss: 15.8 dB

3 dB passband: 907.4-914 MHz (6.6 MHz wide), minimum loss 1.54 dB at 910.06 MHz.

Out-of-Band Rejection

433 MHz (70cm ham / ISM)46.4 dB

700 MHz (LTE 700)48.9 dB

824 MHz (Cellular uplink)47.5 dB

894 MHz (Cellular downlink)53.0 dB

930 MHz (Pagers)53.0 dB

960 MHz (Fixed links)51.7 dB

1090 MHz (ADS-B)52.8 dB

Notes from test

Factory label on this unit reads: Ideal 908.6-912.8 (4.1 MHz), Usable 907.4-914.0 (6.5 MHz), loss -1.21 dB at center 910.7 MHz.

Tested By

Tommy Ekstrand, KG5HZC on 2026-07-11

Sample 20260514001

Download .s2p (902-928 MHz, 101 points)Download .s2p (895-925 MHz, 101 points)Download .s2p (430-1500 MHz, 101 points)

Test Results

S/N 20260326012

At Mesh Operating Frequencies

Meshtastic (906.875 MHz)

Loss: 7.56 dB

Return loss: 3.5 dB

MeshCore (910.525 MHz)

Loss: 1.42 dB

Return loss: 20.2 dB

3 dB passband: 907.5-913.9 MHz (6.4 MHz wide), minimum loss 1.36 dB at 909.8 MHz.

Out-of-Band Rejection

433 MHz (70cm ham / ISM)47.2 dB

700 MHz (LTE 700)49.4 dB

824 MHz (Cellular uplink)46.7 dB

894 MHz (Cellular downlink)48.5 dB

930 MHz (Pagers)50.8 dB

960 MHz (Fixed links)49.9 dB

1090 MHz (ADS-B)48.5 dB

Notes from test

No notes available

Tested By

Tommy Ekstrand, KG5HZC on 2026-07-11

Sample 20260326012

Download .s2p (902-928 MHz, 101 points)Download .s2p (430-1500 MHz, 101 points)

S/N 20260514001

At Mesh Operating Frequencies

Meshtastic (906.875 MHz)

Loss: 8.01 dB

Return loss: 4.1 dB

MeshCore (910.525 MHz)

Loss: 1.66 dB

Return loss: 15.8 dB

3 dB passband: 907.4-914 MHz (6.6 MHz wide), minimum loss 1.54 dB at 910.06 MHz.

Out-of-Band Rejection

433 MHz (70cm ham / ISM)46.4 dB

700 MHz (LTE 700)48.9 dB

824 MHz (Cellular uplink)47.5 dB

894 MHz (Cellular downlink)53.0 dB

930 MHz (Pagers)53.0 dB

960 MHz (Fixed links)51.7 dB

1090 MHz (ADS-B)52.8 dB

Notes from test

Factory label on this unit reads: Ideal 908.6-912.8 (4.1 MHz), Usable 907.4-914.0 (6.5 MHz), loss -1.21 dB at center 910.7 MHz.

Tested By

Tommy Ekstrand, KG5HZC on 2026-07-11

Sample 20260514001

Download .s2p (902-928 MHz, 101 points)Download .s2p (895-925 MHz, 101 points)Download .s2p (430-1500 MHz, 101 points)