02-24-15 16:42 Damon A. Getsman wrote to Ed Vance about Re: Using AX.25 w/older
h

 DAG> @MSGID: 
 DAG>   Re: Using AX.25 packet w/olde
 DAG>   By: Ed Vance to Damon A. Getsman on Mon Feb 23 2015 12:20:00
Howdy! Damon,

 EV> My only experience with Packet on Ham Radio was by using Digicom with
 EV> a circuit connected to my Commodore 64 pc's Cassette Port.

 DAG>   Whoa.  I should've been doing that with my Atari.  Alas, my
 DAG> cassette port was hooked up solely for data storage for a long
 DAG> time.

Probably there was some software/hardware like Digicom for the Atari,
Don't know, Digicom afaik was for use with a C=64.

 EV> The Ham that helped me get started in Packet used a TNC and the Baycom
 EV> program on his 386 pc.

 DAG>   Nice.  I had a friend back in Jr. High, about when 386 was
 DAG> the big thing, that was working with a much more archaic system
 DAG> for packet radio.  Thing was, at the time I never really
 DAG> understood what he was up to.  Wish I would've paid more
 DAG> attention to him now.  :P  I was still online with my Atari

We all learn a little bit at a time, don't we?

 DAG> 130xe at that time (I'd finally graduated from a tape drive up
 DAG> to a 180k disk drive), just starting to learn how to use a
 DAG> modem and really getting into it.

I got the C=64, Floppy Drive and 300 baud Modem to start out with.
I've seen how slow Tape transfers were and didn't want that, I wanted
the FDD even though it was very costly back in 1984.

 EV> I know that doesn't help You any with OpenBSD but I just had to make
 EV> a comment here in case no one else was trying to help You.

 DAG>   No worries.  I'm interested in the full history of things
 DAG> now.  I missed out on a lot of opportunities to learn about
 DAG> this now; I value the background you're giving me and
 DAG> appreciate it.  :)

I just know pieces and bits, and had help learning what I learned from
some other Hams who took their time explaining what's what to me.

 EV> Before I ran Packet, I used a Netronics ASCII/Video board with their
 EV> Keyboard connected to a 555 Audio Oscillator circuit going to the Mike
 EV> Connector of either my 2M VHF FM rig or my HF SSB rig, and a circuit
 EV> for a RTTY Demodulator that I found in a Popular Electronics magazine
 EV> that was connected to the Earphone Jack of either rig.

 DAG>   Well.  Were you just copying the schematics at that
 DAG> point or did you have a bit of the understanding of the
 DAG> electronics theory going on behind that? I've been waiting

This was back in the Mid-1970's when I assembled that stuff.

I saw the 555 AFSK schematic somewhere, just as I copied the portion
of the RTTY Reader project in PE Magazine.
That Reader had maybe eight LED's on the front panel, that scrolled the
words in the RTTY signal data.
Can't remember if they were regular 7 Segment LED chips or what.
Some letters in our alphabet would be hard to configure on a 7 segment
display chip, I'd think.

 DAG> to delve back into electronics; I've got a few high voltage
 DAG> plans that I've had slated for years now, and have just within
 DAG> the past year gotten the parts for.  Unfortunately, right when
 DAG> I was starting work on them, and a fresnel lens oven/omg lazer
 DAG> of death, my stability got blown out of the water.  Had to
 DAG> leave most of my equipment and materials behind.  Still working
 DAG> on getting on my feet again; hopefully it happens soon so that
 DAG> I can have fun lightning to play with again.  Heh.

When You get back into doing that High Voltage stuff be very very
careful and don't let it 'talk' to You.

 EV> I had 10 turn POTS to make Audio Frequency changes to the Demodulator
 EV> Mark and Space settings that I used for RTTY on VHF so I could change
 EV> it when I used it on the HF rig.

 DAG>   This is good info.  I shouldn't be surprised, but I'd not
 DAG> heard of the 10 turn pots before.  I can see how that would be
 DAG> a very good thing in such an application.

I got those POTS from a Ham who salvaged surplus military electronics
to get the parts from them.

Those two 10 Turn POTS came with a calibrated dial that could be locked
to keep it from moving.

They are called "Helipots".

 EV> I had two POTS on the 555 circuit board to adjust the Mark and Space
 EV> settings for either VHF or HF use.
 EV> I used the Standard Mark and Space frequencies when I was on the 2M rig
 EV> but learned that I could use my own frequency settings on the HF SSB rig.

 DAG>   This is all stuff that I need to learn more about.  I've got
 DAG> some manuals downloaded for the test, I'm assuming that the
 DAG> info about the protocols and what these are used for will be in
 DAG> there somewhere...

The VEC Test Question Pool can be downloaded from http://www.ncvec.org
if You want to study them.

 EV> After I built the circuits I tuned my HF radio to the frequency that
 EV> W1AW's RTTY broadcasts were made on.
 EV> When the broadcast started I turned the Mark POT on my Demodulator to
 EV> get the Mark LED blinking, and did the same for the Space POT until
 EV> I could see the broadcast plainly on my TV Set.

 DAG>   Interesting...  You're kind of losing me here..  I wasn't
 DAG> aware you were speaking of video capability.  SSTV is all I've
 DAG> heard about as far as that so far, and from what I've heard

Yes, I wrote about the Netronics ASCII/Video board kit earlier.
It was meant to be a Terminal with RS-232 output.
I just grabbed my connections a little upstream of the output where it
was TTL level.
That's how I was able to connect the AFSK Keyer and Demodulator to
the Netronics kit.

What got me interested was I had read a book called the TV Typewriter
Cookbook and it interested me because someone could get on RTTY without
having the noise and buying paper for it.
I used a cassette recorder to record the receiver audio as I was
reading what was coming on the screen, so I could play it back to see
it later on, if I wanted to.

 DAG> it's a trickle over packet...  So I'm assuming you're talking
 DAG> more about a live analog modulated signal rather than AX.25...

Yes, as long as the difference in the Mark and Space frequencies were
170 Cycles apart, my configuration worked like "Duck Soup".

 DAG> Please correct me if I'm wrong here.  I'm obviously not getting
 DAG> something right, as the demodulator would indicate that there
 DAG> is digital transmission going on here, and everything I've ever
 DAG> seen with 'TTY' in it has to do with slow rate data
 DAG> transmission of an ascii variety...

I could operate at 60 & 100 WPM Baudot, and 110 WPM ASCII.
Never could get 300 WPM ASCII to work with my stuff.

 EV> After the broadcast was over, and before I keyed the transmitter to
 EV> send a CQ, I turned the POTS on the 555 circuit - while either pressing
 EV> my telegraph key or releasing it - to get the LEDs on the Demodulator
 EV> to light up.

 DAG>   What were you transmitting there?

I wasn't transmitting yet, I was just adjusting the AFSK Keyer's Audio
to match what the RTTY audio signal I just heard coming out of my SSB
rig.

 EV> Then I keyed up the HF rig and typed CQ on that frequency and another
 EV> station answered me.
 EV> That is how I had my first RTTY QSO.

 DAG>   Interesting...  This bit of the protocol on things is very
 DAG> helpful for me, I've never been around someone doing this live,
 DAG> so this is all very new to me. Please forgive, again, my
 DAG> ignorance and probably blatantly gumshoe questions here.  ;)

Hey!, Anyone who know me, knows that I'm ignorant about lots of stuff.
I learned by asking questions, everybody does, unless they are inventing
something new that's never been done before.

 EV> I'm not familiar with that rig, sorry can't help You with that.
 EV> Although I know National made some very fine equipment.

 DAG>   No worries.  If you're talking about data over the equipment
 DAG> you were using, I'm pretty sure that the one I'm looking at,
 DAG> while perhaps not made for it, can be induced to transmit my
 DAG> AX.25...  Though for OpenBSD I'm pretty sure I'll need some
 DAG> sort of hardware interface to the modem aspect of things.

Everything I've been talking about pertaining to RTTY has been about
AUDIO.
The Digicom stuff I used later when I got the C=64 converted Audio to
Data on the cassette port, and Data from the cassette port that I typed
on the C=64 keyboard into Audio.
-snip-
 EV> Years later I got a used Hallicrafter SX-42 for my shack.
 EV> 73 and wish You well with what You choose.

 DAG>   Well thank you very muchly.  I really appreciate the look
 DAG> you're giving me into the hobby that I'm working on getting
 DAG> into.  No doubt the first rig I get is going to be something
 DAG> that will be replaced in the future, but I'm actually kind of
 DAG> keen on the idea of having an analog box with replaceable
 DAG> relays... Vacuum tubes would be great (for everything but the
 DAG> power bill), but I'm not going to hold my breath on that bit.
 DAG> ;)  I'm trying to save money, not spend more of it.
 DAG>   Best wishes!

There are many things that Hams are interested in, I've only done a
tiny bit if what Hams do.
But what I do I enjoy, You will enjoy it too, just only put one hand
in the final amplifier, keep the other one in your pocket.  
73

... I to.d yo., "Never.touch .he flo.py di.k su.face!"
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