[pskmail] vhf pskmail progrress

  • From: Bob Morgan <wb5aoh@xxxxxxxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Mon, 12 Aug 2013 20:10:19 -0500


I fixed the compile problem I had on the patched version of fldigi:
Ubuntu has a couple of choices for libfltk: libfltk1.1 and libfltk1.3.
It had both versions installed, but only the dev files for 1.1 and
at random luck that was the wrong version.  Fldigi configure is apparently
only checking for the basic presence of fltk, but not any version or specific
contents.  Uninstalling 1.1 and installing 1.3 made the fldigi compile
run to completion.  So far, so good.

Now for the server.  I got it installed no problem, but at that point I
probably don't know what I am doing or how to drive it, or maybe
more importantly, how to configure it to use the psk1000 and psk1000c2,
and also how to get past the install dialog on it to actually save the choices,
as each time I start it up and answer the questions I haven't any idea how to
get any further so at that point I hit ^C and when I restart it I have
to answer the questions all over again.  Now, I did check and it does post
WB5AOH-1 (the callsign I set up for the server) on your world map so the
beacons do get out to APRS just fine over the internet.  Note that this is
the first opportunity I have had to set up a pskmail server end, I haven't had
the experience of this side of things yet, I have just been trying to get
clients to run.

There were also some unexpected questions that the server install threw at me 
as to
how and where to send mail, and I didn't know how to answer them for
this application.  I was under the impression that each pskmail client
furnishes their own smtp/pop server targets to the pskmail server,
but that the server itself was otherwise ignorant of it.  Is it just a local 
for system messages, or is it a relayserver for everything coming in over the
radio and going out to various smtp servers everywhere, or what?  I run my
own mailserver here, and the popserver exists only on the inside lan
although the smtp server gets stuff from all over the world.
I will fairly soon have to figure out how this stuff needs to be set up,
and for now the ubuntu system itself is unaware of any mail whatsoever
and isn't configured for mail because I don't run mail on it (except as a telnet
session to the mailbox that is on the lan, what I am doing right now).
Also at some point I will have to open up the popserver out onto the
rest of the internet (I am considering a firewall rule to block any pop access
except from specific ip addresses that I can identify as other pskmail servers
I want to actually use if I am running pskmail mobile/portable, but it
is not time for that problem quite yet).

Other problem, and I am pretty sure it is related to configuration, and that is
that I configured fldigi for the new psk1000 and psk1000c2 modes just fine,
and it expands the red boundaries on the waterfall to believable limits,
but after starting up the server, it is forcing the mode back to psk500,
and more importantly, there are no longer any choices on the fldigi configure
menus for the neweer modems, they just disappear from the pulldowns, and I am
sure that isn't what we want to happen.

My objective for the vhf server/client package is to set up and test either
a local audio loop or a vhf radiolink between two ubuntu systems, the desktop
at work for a server and the laptop portable for a client, apart from the
V2 stuff I am already testing for a client on the portable which I am also
working on.  I guess I finally noticed in the mail going back and forth
about the vhf stuff is that you need to verify the new modems on the C++
code prior to porting them over to Java, and that makes lots of sense but I
hadn't thought that far ahead about where it was heading.

One question about the new multichannel psk modes, is where the carriers are
inside the bandwidth that fldigi outlines, how wide each is and how it is laid
out inside that space.  Maybe it might be more obvious after I get to the point 
I start
to see it run and hear what it sounds like, but for now it looks like maybe some
guesswork to find out how stuff is supposed to fit in an audio bandpass.

That brings up a sore subject with me that I run into all the time with packet,
and that is where the datacarriers and sidebands of either afsk or psk fit
inside the audio bandpass of the typical vhf fm radio, that is designed for
voice and uses a pre-emphasis and de-emphasis scheme.  My experience over 25 
years of
packet is that the mike input of a transceiver will include the pre-emphasis of
course, but it will also include some compensation for various microphones or
whatever type, and that mike compensation gets in the way when there is no
microphone involved, and it has also seemed to me that the preemphasis and
deemphasis don't mirror each other very well, and in particular the preemphasis
isn't usually handled very well.  The deemphasis is usually about the same from
one radio to the next, it is just a rc rolloff after the discriminator and 
it is occuring at around the same place that the 1200/2200b afsk tone pair
happens to be.  I have usually had superior packet reception when I either
connect the tnc audio input upstream of that de-emphasis or disconnect the
capacitor entirely, the retry rate quite often goes down quite a bit on
most of the transceivers I have worked with.  Some of the datajacks that some
amateur transceivers include for packet/data usually don't help very much
apart from providing a separate connector, some of the processing is a long
way from a flat passband for anybody's data.  So what I think might be
wise for vhf tests of passbands that are as wide as you are looking at is
to specifically test to see how various radios need to be interfaced to
get best performance.  I would hate to see audio processing in radios clobber
the middle of the data we are trying to evaluate on these tests, and the
potential certainly exists for exactly that to happen.  I would think that
psk would want a flat audio passband, period.

Were you wanting to try out both single and multicarrier psk1000 tests?
I assume that you would when I saw the choices on the fldigi menu,
then I was surprised to see them disappear after starting the server.

I haven't tried the matching client install yet, but anyhow the fldigi
should be the same, I just have to make it work on the portable, maybe that
will still happen later tonight.

As for the V2 jpskmail integrated modem testing, it proceeds on the portable.
I slapped together some improvements to a 30M loop I am using, and while it
is still a little mechanically flaky, it is hearing pretty decent now,
and I was copying KB2PNM beacons in N.C pretty well over the weekend, and heard
AB9FT a couple of times.  30M seemed usually a little better at night to me.
I still have some more radio interfacing and more antenna tinkering to do
before I get it on the air.  For now, it is just acoustic coupling.  I had
also installed xastir on the portable, and it displays the aprs beacons,
and I LOVE that feature.  It hiccuped until I discovered and turned off the
periodic xastir beacon back towards the jpskmail socket.  Maybe that is another
loose end?  Anyhow, it was sending the xastir interface into its error state
until I turned the xastir beacon off, after that it ran fine, displaying what
it received.

73 de Bob WB5AOH

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