Subj : Re: Using AX.25 w/older hardware
To : Ed Vance
From : Damon A. Getsman
Date : Tue Feb 24 2015 04:42 pm
Re: Using AX.25 packet w/olde
By: Ed Vance to Damon A. Getsman on Mon Feb 23 2015 12:20:00
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.
Whoa. I should've been doing that with my Atari. Alas, my cassette port was
hooked up solely for data storage for a long time.
EV> The Ham that helped me get started in Packet used a TNC and the Baycom
EV> program on his 386 pc.
Nice. I had a friend back in Jr. High, about when 386 was the big thing,
that was working with a much more archaic system for packet radio. Thing was,
at the time I never really understood what he was up to. Wish I would've paid
more attention to him now. :P I was still online with my Atari 130xe at that
time (I'd finally graduated from a tape drive up to a 180k disk drive), just
starting to learn how to use a modem and really getting into it.
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.
No worries. I'm interested in the full history of things now. I missed out
on a lot of opportunities to learn about this now; I value the background
you're giving me and appreciate it. :)
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.
Well goddamn. Were you just copying the schematics at that point or did you
have a bit of the understanding of the electronics theory going on behind that?
God I've been waiting to delve back into electronics; I've got a few high
voltage plans that I've had slated for years now, and have just within the past
year gotten the parts for. Unfortunately, right when I was starting work on
them, and a fresnel lens oven/omg lazer of death, my stability got blown out of
the water. Had to leave most of my equipment and materials behind. Still
working on getting on my feet again; hopefully it happens soon so that I can
have fun lightning to play with again. Heh.
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.
This is good info. I shouldn't be surprised, but I'd not heard of the 10
turn pots before. I can see how that would be a very good thing in such an
application.
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.
This is all stuff that I need to learn more about. I've got some manuals
downloaded for the test, I'm assuming that the info about the protocols and
what these are used for will be in there somewhere...
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.
Interesting... You're kind of losing me here.. I wasn't aware you were
speaking of video capability. SSTV is all I've heard about as far as that so
far, and from what I've heard it's a trickle over packet... So I'm assuming
you're talking more about a live analog modulated signal rather than AX.25...
Please correct me if I'm wrong here. I'm obviously not getting something
right, as the demodulator would indicate that there is digital transmission
going on here, and everything I've ever seen with 'TTY' in it has to do with
slow rate data transmission of an ascii variety...
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.
What were you transmitting there?
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.
Interesting... This bit of the protocol on things is very helpful for me,
I've never been around someone doing this live, so this is all very new to me.
Please forgive, again, my ignorance and probably blatantly gumshoe questions
here. ;)
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.
No worries. If you're talking about data over the equipment you were using,
I'm pretty sure that the one I'm looking at, while perhaps not made for it, can
be induced to transmit my AX.25... Though for OpenBSD I'm pretty sure I'll
need some sort of hardware interface to the modem aspect of things.
EV> The High School I went to had a Ham Shack that used a National NC-183d
EV> Receiver.
EV> After I got interested in Amateur Radio I got a Hallicrafter S-38E.
EV> There isn't Any Comparison between what I had at home and the Schools
EV> National Receiver, all I could do was drool wishing I could afford
EV> something better than what I had.
Well there are things you can do, but a criminal record is bad... ;)
EV> Years later I got a used Hallicrafter SX-42 for my shack.
EV> 73 and wish You well with what You choose.
Well thank you very muchly. I really appreciate the look you're giving me
into the hobby that I'm working on getting into. No doubt the first rig I get
is going to be something that will be replaced in the future, but I'm actually
kind of keen on the idea of having an analog box with replaceable relays...
Vacuum tubes would be great (for everything but the power bill), but I'm not
going to hold my breath on that bit. ;) I'm trying to save money, not spend
more of it.
Best wishes!
-Damon
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