900 Mhz External Antennae


I an trying to find an external antenae that will give the maximum foilage penetration possible for the 900 Mhz SM’s.

I am turning away almost half of my service inquires using the integrated SM.

There has to be an alternate solution.

Help, Please!

Try an M2 17 dBi yagi

I second that…


They also make a kit that allows you to pair two of their 17dBi antennas to make a 20dBi gain assembly.

(top item on that page)

We also found some 18dbi antennas, but the mount was not very good. I’ll dig up a url if anyone is interested…

Funny you picked that antennae, I ordered that exact antennae and it came in yesterday.

Results: 3.1 miles from AP, SM’s Side by side, well, about three feet apart.

Viewed from SM’s

Integrated SM = jitter 3, RSSI 1429, -70 Db
Connectorized SM = jitter 4, RSSI 1529, -71 Db

Viewed from AP

Integrated SM = jitter 3, RSSI 1413, -71 Db
Connectorized SM = jitter 3, RSSI 1324, -77 Db

Connectorized seems weaker on transmit side?

Integrated 0 Re-regs
Connectorized with said antennae, 555 re-regs in 24 hours

Set up here at NOC for testing.

The only (easily solved :D) problems I can think of are incorrect polarity or bad alignment.

You’ve got the elements installed horizontally, right? Wrong polarity will cost you about 20dB.

Also, check your alignment, the beamwidth on those is only about 15 degrees.

Those antennas work wonders for us on long shots or with lots of foliage. They’ll easily outperform an integrated anytime.

Polarity, all AP’s and SM’s are set to vertical systemwide.

Are you getting better performance with horizontal?

Motorola Canopy 900MHz integrated radios are horizontally polarized. That’s almost definitely your issue.

Your are exactly right.

I have another 900 Mhz “Datalinc” system for SCADA in town that is vertical.

My mistake.

Flipped it 90 degrees and PRESTO

RSSI from 1496 to 1940
Jitter from 4 to 2
Db from -72 to -60