Antennae not detecting

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Kelsey Sullivan

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Oct 31, 2023, 2:27:55 PM10/31/23
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1 of my three antennae ports is not picking up the two test tags I have.  the other 2 ports are detecting the tags whether I insert in the connection or leave next to the receiver on the table.  Any ideas? I've dialed up the gain and dialed it down quite a bit on both ends and still no detection on the one antennae port.

Josh Sayers

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Oct 31, 2023, 2:28:52 PM10/31/23
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Hi Kelsey, what sort of receiver are you using?

Rich Schramm

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Oct 31, 2023, 3:04:07 PM10/31/23
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Have you tried systematically swapping antenna leads etc.?
First try swapping a known good antenna with a the 'bad' at the connection to the receiver to see if problem moves.

If you are using sdr dongles - try swapping dongles to see if maybe the dongle is bad etc. 

Lastly if you can access the connector on the mast - (usually hardest to access) swap there.

Have you also looked at the sensorgnome or ctt web portal, perhaps you have a lot of rf noise swamping your antenna in one direction. (we have this problem on one of  our antennas - almost too noisy for any beeps to be recognized) 

Also if you have electronics experiene and access to a NanoVNA analyzer you can characterize the antenna to see if its bad (similar to:  https://www.amazon.com/AURSINC-NanoVNA-H-Vector-Network-Analyzer/dp/B07Z5VY7B6)

-Rich

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The Motus Wildlife Tracking System (Motus) is an international collaborative research network that uses coordinated automated radio telemetry to facilitate research and education on the ecology and conservation of migratory animals. Motus is a program of Birds Canada in partnership with collaborating researchers and organizations. Learn more at https://motus.org
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Kelsey Sullivan

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Oct 31, 2023, 3:58:23 PM10/31/23
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SRX800D

Josh Sayers

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Oct 31, 2023, 5:44:29 PM10/31/23
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To confirm, it's a Lotek SRX receiver and 2 of the 3 ports will pick up the signal with the tag beside the connection, but with no antenna connected? 

Two possibilities come to mind...

 -  I think the Lotek receivers have settings that allow you to control which antennas, and how frequently, they are scanning. Might be worth looking into that.

-  If there are no settings that are affecting this, It's also possible there is an issue with the receiver itself.

However if do have antennas attached, then I'd definitely follow Rich's advice and strategically swap "good" for "bad" to see if you can locate the issue.

Josh
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