1. TEST REPORT Twin LNB
该独家报道由技术专家所作
Jiuzhou JTU31
Universal
Twin LNB
• performed very well in output power
measurements TELE-satellite Magazine
• gives better results than announce in
product speciafications
Business Voucher
www.TELE-satellite.info/11/11/jiuzhou
• especially well suited for the modern two Direct Contact to Sales Manager
tuner PVR receivers
• output power measurements better than
our reference LNB
• light weight makes LNB suitable for
multifeed installations
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2. TEST REPORT Twin LNB
Two in One
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Jiuzhou JTU31 Universal Twin LNB
Great performance optimized for Twin
Tuner PVR Receivers
A great Choice For Use
with Twin Tuner PVR Receivers
This is not the first time at practical point of view, two the same dish and
TELE-satellite that we test parameters are of most we measured each
LNBs from Jiuzhou: in TELE- interest to the user: how of the two out-
satellite 10-11/2010 we test- strong is the signal at the puts of those twin
ed their Monoblock LNBF and output of the device and LNBs. We named
in TELE-satellite 06-07/2009 how good it is. In techni- the tested units T1
their Multifeed LNB. What we cal terms, the first is re- and T2 (because
always liked in Jiuzhou is the lated to LNB output power they were Twin
fact that this company does expressed usually in dBμV models) and their
not over specify their prod- (rarely in dBm) and the sec- outputs as “a” and “b”.
ucts. As a true professional ond to MER (Modulation Er- You can see the results
manufacturer, Jiuzhou quite ror Ratio) expressed in dB. for the reference LNB
modestly informed us that To put it in simple terms, (REF) and JTU31s (T1a,
the noise figure of the JTU31 MER is a measure of the T1b, T2a and T2b) on
was 0.6 dB. It may look infe- signal to noise ratio. the attached graphs.
rior to the competition who Measuring two samples
claim usually something like If a LNB has a high out- of same LNB helps us to
0.2-0.3 dB but is that really put power, it is well suited determine that all LNBs
so? You can not tell until you for long cable installations of this series are within
test the product. or an installation with pas- the same range.
The Jiuzhou JTU31 KU band sive splitters that attenuate If we would only
LNB is quite light so it should signal. If a LNB produces a test one sample
not pose any problems even signal of high MER, the re- LNB, we would
in multifeed installations. ception system has a big not be sure if
Because it is a twin LNB, it margin for bad weather the other LNBs
comes with 2 rubber cov- conditions or even a margin of this series
ers for F connectors. At the for slight misalignment of a would give
bottom side of the case, the dish. same results.
JTU31 has three small holes In the beginning of the So testing
for letting out water that test, we installed our ref- two samples
might condense inside. We erence single LNB on a 90 gives us a
measured that JTU31 con- cm offset dish. Then, we good aver-
sumes only 140 mA during mounted two JTU31 sam- age for this
normal operation. ples one after another on LNB series.
As usually, we used HOT-
BIRD on 13° East as our
source of test signals be-
cause this satellite has a lot
of transponders spread from
end to end of the Ku band
frequency range. From a
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3. ■ Testing the Twin LNB JTU31: we
mounted one after the other our
reference LNB and each of the two
sample Twin LNBs JTU31 in a 90cm
Offset dish and measured the results
with a professional satellite meter.
More on This Manufacturer
Read TELE-satellite’s Company Report:
JIUZHOU
Receiver Manufacturer, China www.jiuzhou.com.cn
www.TELE-satellite.com/TELE-satellite-1103/eng/jiuzhou.pdf
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4. The two JTU31s performed say that these LNBs are re- opinion about them is very
very well in output power ally good. Local oscillator ini- positive. A regular satellite
measurements – especial- tial frequency accuracy was TV viewer will be absolutely
ly for vertical polarization. better than 0.1 MHz and its happy with the performance
They were better than our drift from -30° C to +60° of these LNBs, especially
reference LNB by 4 dB on C was only 0.4 MHz for low nowadys with the wide-
the average. 4 dB difference band and 1.5 MHz for high spread use of twin receiver:
is the equivalent of about 12 band. Intermodulation prod- of course, these twin LNB
meters of coaxial cable. ucts specified as -45 dBm models are especially well
When we checked out were in fact -55 dBm and suited for the modern two
the MER results, the JTU31 -60 dBm for the two samples tuner PVR receivers.
looked quite good as well. we tested, so their prod- As an additional advice we
It was practically as good uct in realitiy is better than suggest LNB buyers not to
as our reference single LNB. Jiuzhou’s official technical pay too much attention to
For some transponders specifications - it is always the noise figures. The over-
slightly better for the oth- a hallmark of a profession- all performance of an LNB
ers - slightly worse. But the al manufacturer to deliver depends not only on the in-
difference was really very better performing products ternal noise floor but also on
small, practically negligible than announced. the intermodulation perfor-
– only 0.5 dB. T here are LNBs on the mance and phase noise of
We checked the techni- market that beat our refer- their local oscillators. Only a
cal specifications and the ence LNB in MER readings. real life test like this TELE-
in-house test results of the However, the JTU31 Twin satellite test can truly reveal
manufacturer, that Jiuzhou LNBs were practically equal the effective performance of TECHNICAL
shared with us and we must to our reference and our a new product. DATA
Manufacturer Sichuan Jiuzhou Electric Group Co. Ltd, China
Internet www.jiuzhou.com.cn
E-mail lewisliu@skytrack.cn
Telephone +86-755-26947264 +86-755-26947236
Fax +86-755-26947266 +86-755-26715408
Model JTU31
Function Universal Twin LNB for Ku-Band
I/P Frequency Range 10.7 GHz ~ 12.75 GHz
O/P Frequency Range 950 MHz ~ 2150 MHz
L.O. Initial Accuracy ± 1.0 MHz (@ 25° C)
L.O. Temperature Drift ± 2.0 MHz (-30 ~ + 60° C)
L.O. Phase Noise -60dBc/Hz @ 1 kHz offset(Max.)
L.O. Phase Noise -80dBc/Hz @ 10 kHz offset(Max.)
L.O. Phase Noise -100dBc/Hz @ 100 kHz offset(Max.)
L.O. Spurious -55 dBm (Max.)
Noise Figure 1.0 dB (Typ.) @ 25° C
Conversion Gain 55 dB (Min.)
Gain Variation 8 dB (Max.)
Gain Flatness ±0.5 dB/27MHz
Intermodulation -45 dBm (Max.)
Isolation 20 dB (Min.)
Image Rejection 40 dB (Min.)
P1dB 0 dBm (Min.)
Output VSWR 2.5:1 (Max.)
DC Current consumption 200 mA (Max.)
Polarization Switching Voltage V:11.5~14V, H:16~19V
Band Switching Low:0 kHz, High:22 ± 4kHz
Water Proof Test +60°C water for 5 minutes
Expert Opinion
High output power and good noise perfor-
mance matching 0.2-0.3 dB LNBs
+ Very good intermodulation performance
Very small LO drift
Lightweight
Good workmanship Jacek Pawlowski
TELE-satellite
–
Test Center
None. Poland
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