Author Topic: filter for RX antenna  (Read 4610 times)

ce-uk

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filter for RX antenna
« on: December 05, 2014, 06:48:27 AM »
Hi guys

I have gotten yatebts to recognise my bladeRFx115 and have managed to get it to broadcast a GSM network signal which my mobile can see (Using licensed spectrum).

Now, when I try to connect to the network with my mobile, it times out. Yate does not seem to even mention the fact that a phone has tried to connect which makes me think that either the noise levels are way too high or the BladeRF isn't passing information correctly to Yate. I'm using two of these antennas: http://www.rfsolutions.co.uk/acatalog/ANT-GHEL2-1.pdf

I don't seem to see any logs relating to a phone even attempting to connect to the network though I have tried multiple times with different phones.

Are there any tests for noise that I can run through? I'm thinking of changing the TX power to lower levels as well as adjusting the RX sensitivity but I'm not sure which settings these will relate to  :-\

I can also see on the YateBTS site that the labkit has a filter attached to the RX antenna and I'm wondering if this is what is needed to allow mobile phones to connect. What sort of device is this as I'd like to get one for the GSM 1800 range.

Thanks in advance for any assistance :D

Chris

Diana Cionoiu

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Re: filter for RX antenna
« Reply #1 on: December 17, 2014, 03:33:07 AM »
Try calibrating the BladeRF first.

ce-uk

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Re: filter for RX antenna
« Reply #2 on: January 16, 2015, 11:05:28 AM »
Hi

I've tried using kalibrate but unfortunately has ended up causing the bladerf to be calibrated with an accuracy of 20+ ppm which is enough to just about get a phone connected but not enough for calling..

For someone with limited amounts of kit, is kalibrate the only way to get the bladerf tuned or are there other tools that can be used?

ce-uk

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Re: filter for RX antenna
« Reply #3 on: January 20, 2015, 07:32:21 AM »
I managed to improve the calibration within 0.5ppm with a little help from the nuand post https://nuand.com/forums/viewtopic.php?f=5&t=3633

Even with the improved calibration, calls only have a range of around 15m or so before calls crackle or drop.

Are there any recommendations for reliably increasing the range to between 0.1-1km? something like a pre-amp from http://nuand.com/forums/viewtopic.php?f=10&t=3637 or specific antennas?

thanks

david.burgess

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Re: filter for RX antenna
« Reply #4 on: March 31, 2015, 10:39:15 AM »
Take a look at http://wiki.yatebts.com/index.php/Radio_Related_Problems for some pointers on normal values for power and noise levels.

That said, the normal range of a lab kit should not be more than about 20 meters. It is intended for desktop testing and development work, not large-area coverage.

As for frequency calibration, anything within 200 Hz of the standard should work with no problem.