Different signal strenght rx/tx with dual chain
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brainy
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Different signal strenght rx/tx with dual chain

by brainy » Thu Mar 22, 2012 12:54 pm

Hi there,

someone has an idea what is causing this strange signal strengt?

LOS is ok, distance is ~250m One side is SXT, one side is OmniTIK (screenshot was made on the OmniTIK side) Both sides using "card-rates" with power set to 20 to prevent a too strong signal.

Regards,
Joerg
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rodolfo
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Re: Different signal strenght rx/tx with dual chain

by rodolfo » Thu Mar 22, 2012 1:45 pm

could be:
1. a different propagation from H to V
2. something in radio/pigtail/calbe/antenna

you could discriminate from this two cases, polarizing antennas at 45°. If is the cause 1 the difference must fall near 0.

(remember: some sxt seems to have a problem in chain 1)
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Re: Different signal strenght rx/tx with dual chain

by MrBoni » Thu Mar 22, 2012 8:21 pm

@brainy I have the same problem. Same setup - OmniTik on one side, SXTs (and 711s) on the other. Also, same as me, you have different CCQ levels on Tx and Rx (97% vs 44%).

Don't know about you, but I'm not getting any more throughput if I enable chain1 on SXTs. It's like 2x2 MIMO isn't doing it for me.

If anybody has an idea, don't be shy to share it with us :)


My thread is here: viewtopic.php?f=7&t=60325
Still no reply.

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czolo
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Re: Different signal strenght rx/tx with dual chain

by czolo » Thu Mar 22, 2012 11:12 pm

MrBoni wrote:@brainy I have the same problem. Same setup - OmniTik on one side, SXTs (and 711s) on the other. Also, same as me, you have different CCQ levels on Tx and Rx (97% vs 44%).

Don't know about you, but I'm not getting any more throughput if I enable chain1 on SXTs. It's like 2x2 MIMO isn't doing it for me.

If anybody has an idea, don't be shy to share it with us :)


My thread is here: viewtopic.php?f=7&t=60325
Still no reply.


Maybe it's stupid - but try to rotate the SXT for 90 deg.
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rodolfo
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Re: Different signal strenght rx/tx with dual chain

by rodolfo » Fri Mar 23, 2012 3:42 pm

@MrBoni

your problem (ccq) is very different from brainy (dbm)
in your case could be an interference problem
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Re: Different signal strenght rx/tx with dual chain

by MrBoni » Fri Mar 23, 2012 10:10 pm

rodolfo wrote:@MrBoni

your problem (ccq) is very different from brainy (dbm)
in your case could be an interference problem

I have both low CCQ and different Tx/Rx signals levels!
Why do I have interference? I tried to change the frequency multiple times with no result.

czolo wrote:Maybe it's stupid - but try to rotate the SXT for 90 deg.

I'll try that. But, if I may ask, why would that make any difference if both devices (OmniTik and SXT) are dual polarized?

DynStatic
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Different signal strenght rx/tx with dual chain

by DynStatic » Sat Mar 24, 2012 5:07 am

MrBoni wrote:
rodolfo wrote:@MrBoni

your problem (ccq) is very different from brainy (dbm)
in your case could be an interference problem

I have both low CCQ and different Tx/Rx signals levels!
Why do I have interference? I tried to change the frequency multiple times with no result.

czolo wrote:Maybe it's stupid - but try to rotate the SXT for 90 deg.

I'll try that. But, if I may ask, why would that make any difference if both devices (OmniTik and SXT) are dual polarized?


It won't make a difference if it's dual pol, however if happens after turning it 90 degrees you've ruled out a hardware problem. You can have interference on only one of the poles from a device that's single pole.

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Re: Different signal strenght rx/tx with dual chain

by lazerusrm » Tue Mar 27, 2012 7:08 am

As Above,

Interference can play a large role when you have significant Signal strength variations chain to chain. Interference / Multipath reflections can also cause problems here.


Run a spectral scan, then try out several different channels, and if you notice that the previously low signal chain gets higher signal levels on a different channel, then you have most likely

some interference.

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