Satgen358     Going Digital Pt6   by GM4IHJ              3 Feb 96

The previous 5 satgen bulletins have explored the possibility of moving up
to digital satellites in the way favoured by the majority of Radio
Amateurs who buy, rather than build new , or modify old, equipment. The
problem with following this route is the purchase price of :- A 386/486
micro capable of operating Windows and running Multitasking software ; a
standard TNC plus modems for PSK and FSK ; a high class VHF/UHF dual band
transceiver ;complex circular polarisation antennas together with azimuth
and elevation rotators and suitable masts; plus various software. All of 
which makes a terrific hole in anyones bank account.

It is therefore , no surprise that some cheaper alternatives have been
developed :-

In Satgens 58, 61 and 65 in May/June 1990 , this author described the
modification of a 435/28 Mhz transverter and a 27 Mhz FM CB receiver , to
provide good copy of Uo5 ( and its successors Uo22 and the Koreasats ),
9600 bps FSK downlink.( Satgen file copies are available from GM4IHJ).

In Amsat Journal Jan 91 G0/K8KA briefly described a portable 9600 bps
station

In Amsat Journal March 92 there is a description of a way of using a
70/10m converter and a Ramsey FR10 FM receiver kit for 9600 bps reception.

In Amsat Journal Nov 94, the March 92 article is reprinted and
supplemented by a sophisticated update described by HB9AQZ.

So if you are adept at "Do it Yourself" - home brewing, there is no need
to buy expensive equipment ( which itself will need modifying before you
can use it on 9600 bps).

As yet GM4IHJ has not encountered a cheap route to Ao16, Ao18,Ao19 PSK 
reception. But you can make your own modems. G3RUH has designed excellent
modems for PSK 1200 bps and for FSK 9600 bps. The PCBs are sold with a
very detailed booklet describing the circuitry used, the components
required to be fitted to the PCB , and the setting up procedure.

Meanwhile for operators who only want to copy one or two orbits per day,
the overhead passes provide signals strong enough to be received on simple
antennas, with a home brew crossed dipole or vertical colinear for 70cms
being adequate at IHJ.