Link budget so far EBNO is a symbol

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Link budget so far… EBNO is a symbol and does not equal Eb divided by N 0 (in d. B) EIRP = Pt + Gt Path Loss Signal to Noise ratio

hz)

Other factors that will effect Power Received • Atmosphere; this is transparent at our chosen frequency. • Ionosphere; which is something that needs looking into. • The Effect of tumbling which will pulsate the power and is disused briefly later.

Chosen frequency Information • Using two frequencies we can uplink and downlink at the same time. • 436 MHz (down link) and 146 MHz (Up link) • They are both transparent to the atmosphere. • They will gives us our needed bit rate. • They are in the amateur bands so the licences are easily available

Original Transceiver (DJ-C 7 T/E) Specs • Frequency Coverage; – Uplink: 144 -145. 995 MHz – Down Link: 430 -439. 995 MHz • Modulation; – Uplink: 16 k 0 F 3 E (FM) – Downlink: FM • Output: 300 m. W with EBP 58 N / 500 m. W with 6 Vdc power-source • Power Supply Requirements: 3. 7 Vdc EBP 58 N / 3. 7 - 6. 0 Vdc external power source • Current Drain (approx) ; – Transmitting: 320 m. A – Receiving (squelched): 70 m. A – Receiving (BS-on): 19 m. A • Operating Temperature: -10 ~ +60 degrees o. C

Considerations for aerial • Need to match aerial impedance to the impedance of the transceiver. • Find the aerial length that gives the heights power output. • If two frequency's are used then a trade off will be needed between them both. • Decide on whether a monopole or dipole aerial would be more effective

Experiments That Could Be Done 1. Map transmitted power of the aerial to find any points of low power, this can show the feasibility of using a monopole. 2. Find length of aerial that transmit's the most power. Add an inductor and capacitor so the aerial impedance matches the impedance of the transceiver. 3. Calibrate Radials (if used).

Consider Beacon • Only needs 80 m. W Transmitted Power therefore ~ 240 m. W Total Power. • Can beam down house keeping data constantly. • Is a good failsafe for satellite

Other Considerations • Need to look at Signal Modulations (which is limited by choice of transceiver) • If a packet System is used to transfer data or continuous stream. • Data Link Protocols (which will effect the amount of data that can be transferred) • Will be an analogue signal transmitting digital data

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