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PSM-2100L Satellite Modem Addendum

Page L-Band - 9

with one or more “Hub” stations utilizing 70 MHz as the IF and many remotes utilizing both 70
MHz and L-Band equipments works well without consideration to the particular equipment at any
site. New sites in an existing system may be added using either L-Band or 70 MHz as the IF link
frequency.

5.0

Specifications

The specifications for the PSM-2100L are included at the end of this document

Содержание PSM-2100L

Страница 1: ...z of RF spectrum Aside from the many advantages using L Band as an inter facility link frequency results in the need to carefully consider the components frequencies and construction techniques used to insure proper operation Part of the purpose of this addendum is to spell out those areas where special care must be used to achieve a reliable station operation For the purposes of the remainder of ...

Страница 2: ... 5 150 GHz The PSM 2100L provides two methods of specifying transmit and receive frequencies Added transmit and receive parameter inputs are provided for the transmit BUC and receive LNB Local Oscillator LO frequencies On the front panel display they are referred to as MOD Cnvrter LO and DEMOD Cnvrter LO 1 If a zero frequency is supplied here then the user inputs L Band IF frequencies 950 to 1650 ...

Страница 3: ... Notes C Up 5925 6425 Low 4900 No Common C Up 5925 6425 High 7375 Yes C Up 5850 6350 High 7300 Yes Brazilian C Down 3700 4200 High 5150 Yes Common C Down 3700 4200 Low 2750 Yes Not used Ku Up 14 000 14 500 High 15 450 Yes Ku Up 14 000 14 500 Low 13 050 No Ku Down 11 700 12 200 Low 10 750 No Common Ku Down 11 700 12 200 High 13 150 Yes Of course there are many possible frequency ranges used for sat...

Страница 4: ...of cable used The LNB gain and cable loss variations due to temperature changes are unimportant on the receive side as long as the overall gain range above is met at all times The standard Datum Systems supplied Receive Bias T Mux provides impedance conversion from a 75 Ohm LNB and cable to the 50 Ohms used by the demodulator An additional cable loss of 6 dB should be added to the input level rang...

Страница 5: ...Is 200 Hz to 750 kHz 3 0 Designing and Setting up an L Band Station The equipment complement at any station site almost always consists of transmit and receive equipment including Modem s UpConverter and Downconverter Power Amplifier and Low Noise Receivers as well as the antenna itself In an L Band IF station the locations and complexity of these items is changed The basic station diagram below s...

Страница 6: ...in a data application This is mainly because these LNBs were designed with a very wideband video carrier in mind and the phase noise performance is far from that necessary for a lower data rate PSK carrier Today data grade LNBs are still fairly inexpensive but a prospective LNB must meet certain minimum requirements Gain of approximately 45 to 70 dB Maximum phase noise levels need to be determined...

Страница 7: ...uencies the loss variation with temperature can be extreme For example a 200 foot length of RG214 cable double shielded in class has approximately 20 dB of loss and a variation vs Temperature of 0 2 of dB per degree Centigrade If operating in an exposed environment like a desert where the temperature may vary approximately 20 deg C from day to night that could represent a variation of almost 1 dB ...

Страница 8: ... costs per foot Recommended cables are shown with asterisks Since maximum loss is preferred to be 20 dB or less then generally the cable size is chosen to keep the cable loss well below that point 10 to 15 dB is probably a better design guide considering that other connection losses are inevitable DC resistance for the transmit cable should also be considered with respect to BUC current draw volta...

Страница 9: ...motes utilizing both 70 MHz and L Band equipments works well without consideration to the particular equipment at any site New sites in an existing system may be added using either L Band or 70 MHz as the IF link frequency 5 0 Specifications The specifications for the PSM 2100L are included at the end of this document ...

Страница 10: ...presentation for binary programming of the modem Like the front panel controls the remote control procedures for specifying transmit and receive IF frequencies are dependant upon wether an upconverter and or downconverter LO frequency has be supplied If a non zero frequency has been input from any source then the transmit and receive frequency becomes the RF operating frequency as described in sec...

Страница 11: ...dBm to 35 0dBm Mod Spectrum NEW 29h MSP 0 Normal 1 Inverted 0 Normal 1 Inverted Mod Cnvrter LO NEW 2Ah MLO Either 0 OR BUC LO frequency e g 4900 000000MHz Either 0 OR BUC LO frequency e g 4900 000000MHz Demod CXR Frequency MODIFIED now 5 bytes in binary 41h DCF 950 000000MHz to 1650 000000MHz Only if Demod Cnvrter LO 0 950 000000MHz to 1650 000000MHz Only if Demod Cnvrter LO 0 Demod CXR Frequency ...

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