Satgen36 6th Dec 89   Pacsat preps ,QPSK ,Pacsat antennas ,HF sats

With no JAS1-A Fuji available have been testing Fuji PSK modems on
terrestrial links with GM4JJJ . In this mode both stations transmit PSK
noting that RUH modem sends PSK if connected to SSB input of Tx, thus
behaving like the pacsats we will soon be listening to. Tuning is very
sharp. One 50Hz step up or down and you get nothing. You can use the modem
meter and up down lights as a tuning aid but there is no continuous signal
unlike Fuji, so nothing for your AFC to lock to. Fuji modems we are using
are modified to output  RxDCD. Big problem is that the modems output 1200
Hz to the Tx which is not central in the SSB bandwidth. We only averaged
about one connect in 16 tries in this state.  G3RUH recommends breaking
link LKC and injecting 1500 Hz approx into TP4. In this state we got a
useful link with very few retries. Intend to make a permanent switched
1200 or 1500 Hz inject. Suggest anyone else doing this also tunes near
1500Hz so we all finish up in the same place.
  Am continuing to use TNC320 for PSK but cannot use it for file transfer
because of data flow problems. Several TNC 320s show the same problem.
  Was asked recently if the new 9600 baud narrow band telephone modems
will work on Uosat D. No , not at the moment. Use G3RUH 9600 modem
for Uosat D. The narrow band modems can plug into audio socket because
they do not use BPSK (180 deg shifts). Some use QPSK Quaternary phase
shift keying 90 deg shifts, so 4 states possible ,with each shift
representing 2 bits, thereby achieving a bit rate reduction and hence
narrower bandwidth, but at the expense of a drop in sig/noise. Pacsats may
use this sort of system one day but not at the moment. Though it is in use
on Inmarsat on several channels above 1537.5 MHz azimuth 216 from Scotland
if you want to hear it. It is a strong signal on a 2m dish.
  Pacsat antennas  Given the present mild weather I am going ahead
remounting a 5 XY 2m yagi and a 10 XY 70 cm yagi onto my minitower with Az
El training. Fuji was impossible with my narrow beam 10 XY 2m and,4 by 12
XY 70cm yagis . These were fine for AO10 and 13, but not for fast moving
Pacsats. I did try co linears to see if I could avoid antenna training but
it did not work out too well. I got generally good signals but once in a
while the signal vanished. I will keep the colinears up, but I want the
wide beam trainable antennas to be sure I do not miss the Pacsat fun.
  I have not yet seen any details of Pacsat connect callsigns , and
although I did see the NK6K and G0/K8KA paper suggesting Broadcast
protocols for Pacsat ,have not seen anything since,on that topic 
  Salyut 7 has given some excellent visual passes on recent evenings and
the associated 19955 KHz beacon is providing excellent sub horizon
propagation particularly from just north of Cape Horn after dark here in
Scotland around 1600 onwards. The beacon note is horribly auroral at
times. It seems to have best propagation sub horizon towards UK, at around
UK sunset,whatever its equator crossing longitude
  Hope this Satgen gets through to readers . Have been losing recent bulls
in a blackhole which seems to have developed in Yorkshire/N East England .
73 de John GM4IHJ@GB7SNE  6th Dec 89