10 Oct
2012
10 Oct
'12
11:06 p.m.
Andrey Sviyazov, this question is probably for you,
IIRC, both nanoBTS and SysmoBTS have separate antennas for Rx andTx and do
not use duplexers. Do we need duplexer for UmTRXv2 if it operates in the
low power mode, without an additional PA/LNA?
--
Regards,
Alexander Chemeris
CEO, Fairwaves LLC
http://fairwaves.ru
11 Oct
11 Oct
7 a.m.
Hi Alexander.
If Tx level very small and Rx path not saturated, than you should check Rx
noise flour to be sure that TX doesn't jumm Rx.
Anyway it all about Rx sensitivity only.
Best regards,
Andrey Sviyazov.
(Sent from my mobile client)
11.10.2012 1:07 пользователь "Alexander Chemeris" <
alexander.chemeris(a)gmail.com> написал:
Andrey Sviyazov, this question is probably for you,
IIRC, both nanoBTS and SysmoBTS have separate antennas for Rx andTx and do
not use duplexers. Do we need duplexer for UmTRXv2 if it operates in the
low power mode, without an additional PA/LNA?
--
Regards,
Alexander Chemeris
CEO, Fairwaves LLC
http://fairwaves.ru
7:58 a.m.
Hi,
IIRC, both nanoBTS and SysmoBTS have separate antennas
for Rx andTx and do
not use duplexers. Do we need duplexer for UmTRXv2 if it operates in the low
power mode, without an additional PA/LNA?
Note that both still have internal filters.
Antenna design also plays a role. The nanoBTS uses patch antenna
separated by a lump of metal to minimize direct radiation from TX to
RX.
Cheers,
Sylvain
12:21 p.m.
On Thu, Oct 11, 2012 at 9:58 AM, Sylvain Munaut <246tnt(a)gmail.com> wrote:
Hi,
You mean bandpass filters? Are they only on Rx side or both Tx and Rx?
IIRC, both nanoBTS and SysmoBTS have separate
antennas for Rx andTx and do
not use duplexers. Do we need duplexer for UmTRXv2 if it operates in the low
power mode, without an additional PA/LNA?
Note that both still have internal filters. Antenna design also plays a role. The nanoBTS uses
patch antenna
separated by a lump of metal to minimize direct radiation from TX to
RX.
Yes, I remember that nanoBTS has patch antennas for better isolation.
But IIRC sysmoBTS has rubber duck antennas which made me wonder how do
they do Tx/Rx isolation.
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
1:01 p.m.
Hi,
You mean bandpass filters? Are they only on Rx side or
both Tx and Rx?
Yes, bandpass filters. (SAW or Ceramic, possibly both)
nanoBTS has both side. You can clearly see them here :
http://openbsc.osmocom.org/trac/wiki/nanoBTS/Internals
sysmoBTS I know has RX filters, I don't remember about TX.
Yes, I remember that nanoBTS has patch antennas for
better isolation.
But IIRC sysmoBTS has rubber duck antennas which made me wonder how do
they do Tx/Rx isolation.
Mine actually shipped without antennas :p
I use it with rubber duck in lab tests but I don't know if it's a
recommended configuration.
Cheers,
Sylvain
1:06 p.m.
On Thu, Oct 11, 2012 at 3:01 PM, Sylvain Munaut <246tnt(a)gmail.com> wrote:
Hum, I don't see how is that different from a duplexer if they have
both Rx and Tx filters. Do you know any particular reason for this
design?
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
You mean
bandpass filters? Are they only on Rx side or both Tx and Rx?
Yes, bandpass filters. (SAW or Ceramic, possibly both)
nanoBTS has both side. You can clearly see them here :
http://openbsc.osmocom.org/trac/wiki/nanoBTS/Internals
sysmoBTS I know has RX filters, I don't remember about TX.
1:10 p.m.
Hi,
It still exposes independent TX and RX lines allowing for external
amplification / filtering if required.
Also in a duplexer you have a direct electrical connection rather than
TX->RX radiation which means you need much more attenuation (often
requiring the duplexer + subsequent band pass filters).
Cheers,
Sylvain
nanoBTS has
both side. You can clearly see them here :
http://openbsc.osmocom.org/trac/wiki/nanoBTS/Internals
sysmoBTS I know has RX filters, I don't remember about TX.
Hum, I don't see how is that different from a duplexer if they have
both Rx and Tx filters. Do you know any particular reason for this
design?
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6 comments
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Alexander Chemeris -
Andrey Sviyazov -
Sylvain Munaut