Last years we (hm, mainly S53MV) developed PSK radios using 1.288 Mbit/sec.
Heavy users are now soldering 23cm radios.
Old 13 cm radios are good, robust and comlicated, so they are on hilltops.
There is a younger 13cm radio, simmilar to 23cm design.
All projects are:
- published in Slovenian HAM magazine CQ ZRS
- whatever is available in English is on http://www.hamradio.si
Some designs are published in Weinheim proceedings, and in last ARRL CNC
proceedings.
I would suggest looking into 23cm PSK radio: it works fine, it is not
complicated, and, most important, it works with no tuning !
(ok, it works better after tuning, but few HAMs reported making QSOs
before tuning).
S57MMK modified Pi-card (based on SW reverse engineering, we got Pi-card
shematics to late to influence design). It has scrambler for PSK radio on
DMA port and manchester modem to be used with WBFM on IRQ port.
IRQ port acts as Baycom USCC card also, so WBFM only users can run TFPCX or
old Flexnet drivers.
S57MMK also modified Pi-card driver for Linux 2.0.0 and it works fine
on 1.288 Mbit/sec. TXDELAY and RESPTIME timings are done in driver:
each milisecond on 1.288 Mbit/s is same as one second on 1200 bps.
Imagine having 1200 bps packet with 100 seconds timers resolution ?
There is also Flexnet driver and FTP packet driver for this card.
SW and schematics are available, but ... translating into English has
very low priority (it is fun doing things, but documenting ?) so
S57MMK is not yet on http. I hope we can report soon that it is there.
And next step: when we fill up nodes with users using 1.288 Mbit/sec,then
it is time for 6 cm backbone. But, of course, faster as users QRG.
Also, out nodes are currently not fast enough for 1.288 Mbit/sec.
Even with 68020 upgrade it is still loosing too many frames in SW.
Original 68010 based design has 68450 DMA and SCC, and it is sone in
pooling, because we could not figure out how to make IRQs usable.
So, it is also time for next design.
But, until this is QRV, system works and we have fun !
73 gl, Iztok S52D
Ham: vebvv.tfcwmsw@cildro.ro (gcizfyvn.lyjmuxgtyj@rele.tunk.net when ljutcpis QRV)
QRL: yajnd@sgi.com
W0RLI BBS network: pti.tapt@ancheim.ie