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Re: Re: RE: Geo Opportunity



On Wed, 30 Jul 2003, Keith N6ORS wrote:

> ok, this is for a Mode K transponder.  21.4 mhz uplink /29.4 mhz dnlink.
> Using 5w on the uplink (portable qrp type nuts) , and 10w (single
> signal) on the downlink.

Yes, but if you use HF for the downlink, you have to throw in 18 dB of
atmospheric noise to the link equation which washes out all advnatages of
the better link budget.  That is why we only planned to use 10m for uplink
(where it has hardly any noise out at GEO)...

I think...

Bob

> This would work nicely with a diplexer and a single tape whip with a 3/8
> wave on 10m (1/4 on 15m).
>
> Keith (N6ORS)
>
>
>
> Uplink 15m
> TX power          5W    37 dBm
> TX Antenna Gain          3 dBi
> Polarization loss       -3 dB
> Resulting EIRP          37 dBm
> Path Loss at 10m      -150 dBm
> Receiver Antenna Gain    0 dBi
> Received signal       -113 dBm
> Required for 10dB SNR
>   in 3 KHz bandwidth  -119 dBm
> ------------------------------
> Margin                 +6 dB
>
> downlink 10m
> TX power         10W    40 dBm
> TX Antenna Gain          3 dBi
> Polarization loss       -3 dB
> Resulting EIRP          40 dBm
> Path Loss at 10m      -153 dBm
> Receiver Antenna Gain    0 dBi
> Received signal       -113 dBm
> Required for 10dB SNR
>   in 3 KHz bandwidth  -119 dBm
> ------------------------------
> Margin                  +6 dB
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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>

de WB4APR@amsat.org, Bob

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----
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