Human body interference

1

Hello All,

I have a 4 antenna UCA pedestrian mobile array antenna inside a backpack, its radius is 10.5 cm.

Despite the small size, it seems to work well enough at 144 MHz band.

At 432 MHz band I would say that only works with very strong signals. You need to be only about 200 metres away to get good bearings.

In some other experiments with human body presence near the array, I also got bad results.

I do not know if the actual cause is the proximity of the human body or any other. Perhaps I did not perform my tests all right.

Please, anyone has some experience with these setups? Could you tell us?

Thank you,

German EA4GJA

2

If the array is raised up above the human body, it won’t be a problem.

If it’s below, then the human body is just acting as a signal blocker, which will obviously cause issues as the array can’t see the signal directly.

3

The array is below the human body, inside the backpack.

I am trying to replicate the issue, I would say that when the human body is between the array and the transmitter, the kraken sdr gets less signal as you said. In such cases reception can be lost, and bearings can be erratic.

In the tests I did at home, when the human body is NOT between the array and the transmitter, but near the array, I would say the main lobe can skew about 25 degrees, it keeps pointing an approximate bearing. You should arrive to the transmitting site, only you could need more time.

Perhaps the human body is a little issue, and a bigger one is multipath. I can remember now some other tests in Madrid with the array over the body. In the end the transmitter was found, but multipath in a big city is a problem and you need to insist.

I will keep trying.