Hams in Space!

telemetry on one side and Fuji-OSCAR transmissions
on the other. Thc AO~ 13 material is
nOI germane 10 this discussion. bUI the Fuji
material is of considerable value. Feed the
output of the tape recorder directly 10 the
phone plug on the cable going 10 the modem.
Fire up the PK-232 and you should be receiving
FO- 12 material without any trouble.
The Ri~ht &ltin~s
Now we arc ready 10 get on the air. The
first thing 10 do is to re-config ure some ofthe
parameters in the PK-232. The fo llowing has
been found successful: nWAIT 32, FRACK
6. FUlLDUP ON, IIEADERlN ON .
:\IAXFRA~l fo: 2 . PAC LEN 32,
PACTI:\II~" 10, and TXDELAY fH. On
the TAPR modem. the left-hand swuch is
" up" or on MAN. and the next, center. Then
the next is " up" or ON, and the right-hand
swuch is " up" or JOI NT. Set the audio gain
control on the radio so that the left-hand bar
display on the modem is around the 71h or 81h
bar. Tune in the microsat downlink unt il the
right-hand bar display indicates that rhc loop
is centered. (When you were adjusting the
modem. you determined wh ich bar would
indicate Ihi s.) An oscilloscope connected to
the PK-232 is a great help. and if you have a
suitable one you might consider leaving it as
pan of the permanent installation. I use a
Kenwood SM-220.
Put the loop-centered switch in the STF.P
switch to either USB or LSB. depending on
your receiver luning. Use whichever setting
tracks correctly. The loop should remain ccntcred
rnrocgnouubc satellite pass. and should
not nicker either up or down. If it does. your
" dead band" is 100 wide.
If all is well. you should now be receiving
the downlink perfectly. First, try connecting
to your station through either Pacsat or Lusat.
For example, KI6QE V LUSAT-I. Keep the
transmitter output to 20 walls or less. and use
the FM-N position on the FT-736. Ifyou are
using an FT-726. be sure the deviation is less
than 3 kHz. You should connect almost immediately.
Be sure you are using the correct
uplink frequency; see the table. You don't
have to track the uplink frequency for
Doppler since the microsat has suffic iem
bandwidth 10 compensate. However, if you
are a purist. you may wam to adjust me uplink
frequency at the beginning, center, and end
of the pass to maintain continuous connect.
Now you can try FO·20, First, tunc in the
downlink as before on435. 910 MHz , thentry
to connect with the Mail box. Use the callsign
8J IJ BS. Please notc that there is no digipcater
, so do not try to connect to yourself. II
won't work. When you get the connect. wail
for the prompt JAS > . If you issue a command
before this. you'll get frame-reject respouses.
and you'll have to disconnect and
Man again. Pressing II will bring a short help
screen, and you can go from there .
All these packet microsats have four uplink
frequencies. You can select the appropriate
uplink frequency in accordance with the following
formula. suggested by HB9AQZ to
avoid congestion on the uplinks: I. If your
callsign ends in a letter from A-G; 2. if your
10 73 Amateur Radio Today . March , 1991
callsign ends in a letter from H-M; 3. if your
callsign ends in a letter from N-T; and 4. if
your callsign ends in a leiter from U-Z.
Now. a word about the FT·736 radio. II has
a small jack on the back that short-circuits
most of the audio processing circuitry . This
DATA tN/OUT jack is well worth using for the
FM data input from the PK-232. Instead of
connecting from the TAPR modem 10 pin 8
on the mike connector. take it to the sleeve of
a miniature stereo connector and plug this
into the above jack. Don't forget 10 include a
ground connection as well.
You will be surprised at the improvement
in your uplink performance . Connection is
usually achieved at the first or second attempt,
and through-put is as good as or. in
many cases, better than with the local terrestrial
BBS. You can even do better than this by
laking this connect ion directly to the junction
ofR32 and C39 in the TX unit ofthe 736, but
unless you are willing 10 get into your new
and expensive radio with a soldering iron. I
suggest that you fo rego this dubiouspleasure,
and put up with the " substandard" perfo rmance
as described above.
The'Sonware
A number of packages are available. Most
ofus sian with a simple communications program,
such as PC-TALK or PROCOMM ,to
interface the computer and the PK·232. This
is adequate and flexible. but you have to set
things up and remember key commands. PC­
PAKRAIT from AEA conveniently automates
most of lhe functions you need. but u's
hard 10 modify, and it hasn't been updated for
the latest developments.
For example, if you want 10 use KISS or
some of the newer commands, you have to
resort to dumh terminal mode. which has no
real advantage over the simpler communications
programs above.
A newer shareware program called LAN­
LINK retains most of the automation of PC­
PA KRAIT while keeping the flexibility of
the simpler programs. You can obtain this
from many BBSs and CompuServe.
The QU31/;i System
The installation described uses a dual
home-brew quagi system with 2 x 9 elements
on 2 meters. and 2 x 16 elements on 70cm
with auto tracking, as already indicated. Others
have obtained perfectly satisfactory operarion
with vertical antennas for both transmit
and receive. If you choose to go this route, be
prepared to put more RF power into the antenna;
you' ll need at least 100 watts EIRP. If
reliable performance is your goal, experience
indicates that perhaps 200 watts EIRP is a
better fig ure.
Finally. what about all that neat telemetry
thai pours onto our screens? Whal does it all
mean? It's a running commentary on the
health of the satellite. There are programs to
decode this data into more meaningful numbers.
A program called TLM DC is available
from some BBS facilities as well as from
AMSAT. This decoder requires your PK-232
to be in KI SS mode 10 operate properly.
TLMDC takes binary data from the downlink
and writes it directly to disk. or decodes it to
me screen or another disk file. KISS is available
on all PK-232 machines. However, if
you don 't have the 1989 firmware. you need
10 change the follo.....ing parameters to gel into
the KISS mode: KISS OS, IlPOlL OFF.
PPERSI~'" ON. RAWHOLC ON . COS­
MODE TRANSPARENT. and HOST
Ol'i. If you have the 1989 fi rmware in your
PK·232, all you have to do is type KISS ON
at the CMD prompt.
As soon as you have entered these parameters.
exit the communications program and
bring up TLMDC by ty ping TLMDC
CO~I1 :I200 ,n,8 .l. You will be able 10 sec
the actual telemetry in meaningful numbers.
Another program. WHATS-UP. is available
from Joe Kasser G3ZCZ at P.O. Box
3419, Silver Spring MD 20918. It doesn't
require KISS. having its own communications
program. and it' s probably the best way
to go if you are just starting up.
There arc two land-line BBSs which carry
AMSAT news and the software referred 10 in
this article. The official AMSAT board is
operated by the Dallas Remote Imaging
Group at (214) 394- 7438. In Southern California.
the Califo rnia Astronomers Group
has a section in their BBS, phone number
(714) 738-433 1, for AMSAT; il carries the
sarnc material as the Dallas BBS. I'd be more
than happy 10 assist you with problems in
similar systems; you can write 10 the address
below. but please send an SASE with your
request.
Since this article was first prepared some
dramatic new developments have taken place
in the Microsat World. Both LUSAT (LO­
19) and PACSAT (AO- 16) have new BBS
software loaded and ope rating. To lake advantage
of these very advanced technology
satellites you will need the following software
packages in your ground slation. These
arc obtainable from AMSAT.
PR.EXE This program allows you 10 copy
broadcast bulletins, ell'.
PG,EXE This allows you 10 gel a file directory
and 10 up and download fi les.
rfllADn,EXE This prepares files for up-­
loading. You cannot upload without first using
this utility.
PIIS.EXE This processes downloaded
files and allows you 10 display their contents.
II is imponant to note that PG requires your
TNC 10 be in the TRANSPARENT mode,
whereas PB requires KISS mode. This causes
PK-232 users some inconvenience in switching
from one program to the other whereas if
you are using a TNC-2 this is not so.
This is a fast developing field so keep your
eyes on the AMSAT Bulletin Boards. In parneuter.
watch the 75-meter nels on Tuesday
evenings on 3.840 kHz. III
David Mt'd/t'), KJ6QE ",as fim licensed in
Australia as VK3MJ in tht' '30s. He emigrcaed
to this country with hisfamily in the early
'60s to wort f or the Collins Radio Company
in Dallas, Texas. He retiredin /987. You may
contact him ot 1450 Bayview Heights Drive,
Los Osos CA 93402. Again , please includean
SASE.