[amsat-bb] Re: S Band UP

i8cvs domenico.i8cvs at tin.it
Fri Sep 15 04:03:11 PDT 2006

----- Original Message -----
From: <sco at sco-inc.com>
To: <amsat-bb at amsat.org>
Sent: Friday, September 15, 2006 7:28 AM
Subject: [amsat-bb] S Band UP

> I now have 2m, 70cm and 2.4ghz antennas for satellites. The radio is
> a Ft-847 with receive SSB preamps on V and U bands.
> I have a BBQ dish with a SSB 2.4 ghz downconverter. That will work
> fine with P3E (it did with AO-40). Could I still use the same dish
> for S Band uplink on Eagle?

Hi Les, W4SCO

For the uplink on Eagle you should transmit some where between 2400 to
2450 MHz and as far I know the exact frequency segment has been not yet

If the uplink of EAGLE will be made between 2400 to 2402 MHz then to
use the same dish of P3E you need a coax relay at your dish with the common
port C connected to the feed.
The NC contact will be connected to input of your actual S-band
downconverter and the NO contact must be connected to your S-band TX
amplifier a not easy task if you run a long transmission line because in
this case the TX amplifier must be antenna mounted.

Probably to uplink the S-band on EAGLE a separate dish which size depends
on your needs is easyer. (look at EaglePedia) 

I would need some form of a upconverter
> (from 70cm to 2.4 ghz) plus a amp, to make that work?

You don't want to use P3T and Eagle at the same time and so for EAGLE
you need an upconverter from 2 meters to 2.4 GHz  +  a power amplifier
antenna mounted depending on your transmission line losses (I have a
144-146 MHz to 2400-2402 MHz transverter + 10 watt linear amplifier
mounted at the dish for AO40) and so if EAGLE will likely use an uplink 
between 2400 to 2402 MHz I will be very luky.
> If I am using the S band for the uplink which band am I using for the
> downlink?  2m or 70cm?
The downlink of EAGLE will be made some where between 5830 to 5850 MHz
and as far I know the exact frequency segment has been not yet decided  but
you need a downconverter specifically designed to receive the above band
when it will be chosen.
Now if your 2.4 GHz upconverter uses a 2 meter IF then you must use a 70 cm
IF for your 5.8 GHz downconverter.
A 70 cm IF allow you to get a better receiver image rejection on downlink
while not to be IF to IF interfered using a 2 meters IF for the uplink. 

> Les W4SCO

73" de

i8CVS Domenico

More information about the AMSAT-BB mailing list