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ZL3AI > APRDIG 17.02.04 14:14l 322 Lines 12625 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: RE: New option for HF 30M APRS -- TinyTrak 3b (Review)
From: Jeff King <jeff@aerodata.net>
Date: Sun, 15 Feb 2004 16:23:46 -0500
X-Message-Number: 12
On Sun, 15 Feb 2004 11:20:31 -0800, Scott Miller wrote:
>I've been thinking about implementing this in the OpenTracker as
>well.
.....
>My biggest obstacle to implementing 300 baud is that I don't have
>anything to test it with. I have no HF equipment right now, except
>for a shortwave receiver. I'm not sure what the standards are,
Since your not having to worry about existing users, I'd skip the ax.25 300
baud on HF. Very unreliable on HF in general. I'd develop your own compact
format using something like PSK31, domino or MFSK on HF. The problem with
300 baud AX.25 is multi-path/group delay, which smears the packets. All the
modern sound card HF modes limit the baud rate, even the "fast ones" such
as Pactor3 and Q15X25, limit the baud rate (they gain the speed by using
OFDM type modulations, which have multiple low baud rate carriers).
I have some C source code for the PIC's to do PSK31 transmit if your
interested. There are also open source applications for doing PSK31 on
Windoze and Linux.
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Subject: RE: Problem with PK-232 and APRS
From: "Michael Hatzakis" <mike@hatzakis.net>
Date: Sun, 15 Feb 2004 13:35:02 -0800
X-Message-Number: 13
decided to resort to recalibration. Has someone done this? I have managed
to calibrate, but I realized, I am not sure the status of the 'D' command
that toggles between the HBAUD rate and the continuous rate?
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Subject: Re: Problem with PK-232 and APRS
From: Ken Collins <g4fip@btinternet.com>
Date: Sun, 15 Feb 2004 23:47:30 +0000
X-Message-Number: 14
In article <LYR26201-178912-2004.02.15-14.06.26--g4fip#btinternet.com@li
sts.tapr.org>, Michael Hatzakis <mike@hatzakis.net> writes
>I am trying to get back into APRS after being off while I focused on
>building my AO-40 satellite station, and now am turning back to APRS. I
>would like to use my PK-232 as my TNC for my Icom 910H as it has the
>highest capabilities with the new DSP Timewave upgrages. Problem is, I
>can't get it "see" packets. I am wondering if this is a calibration
>problem? Ideas?
This is probably due to the PK-232 being left in 'host mode' after using
the proprietary Terminal program.
Solution. Run the Terminal program and from the menu select to exit
'host mode' when you close it. You should now be able to run it with any
of the APRS programs currently available.
--
Ken Collins - G4FIP
E-mail:- g4fip@btinternet.com
http://www.btinternet.com/~g4fip
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Subject: Re: Problem with PK-232 and APRS
From: "Michael Hatzakis" <mike@hatzakis.net>
Date: Sun, 15 Feb 2004 16:02:42 -0800
X-Message-Number: 15
Tried that too. I did a hard reset and started from scratch. Thanks for
replying, any other ideas?
Michael K3MH
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Subject: Dayton APRS Events
From: "Jason Rausch" <ke4nyv@hamhud.net>
Date: Sun, 15 Feb 2004 19:27:9
X-Message-Number: 16
Has there been any discussion yet about the APRS Pizza get together or
anything like that for this year's Dayton? I was surprised that there
wasn't anything referring to Dayton on the TAPR homepage by now, like a
banner. I take it there will be a banquet this year.
Jason KE4NYV
www.ke4nyv.com
RPC Electronics
www.ke4nyv.com/rpc
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Subject: RE: HF 30M APRS -- TinyTrak 3b is a couple of years behind TM1+ on
this !!!!
From: "Stephen H. Smith" <WA8LMF2@aol.com>
Date: Sun, 15 Feb 2004 17:39:30 -0800
X-Message-Number: 17
>-----Original Message-----
>NYET, NADA, NAY, NON, Nope ;)
>
>If you look at the TigerTronics TM1+, you'll see that it has had this
>capability for YEARS (both 1200 VHF and 300 HF - in Mic-E, or if you
>want Plain text strings... not to mention beacon mode, and telemetry
>mode - not to mention multiple instances of each...
Mic-E (which is an abbreviation for "Mic Encoder") refers to 3 different
things:
1) The idea of sending an APRS position burst at the end of a voice
transmission (rather than periodic beaconing on a non-voice channel).
2) A highly-compressed transmission format that uses non-text binary
representation of the lat/long/icon data, and uses part of the unproto
address field for data, to send a posit in a barely 1/2-second 'squawk"
suitable for tail ending a voice transmission. Information on the
encoding format is part of the "official" APRS 1.01 Specification PDF
document downloadable from tapr.org.
3) A hardware device that inserted between the mic and the radio to
send this kind of data burst. A rotary switch on the front of the unit
allowed you to select one of 8 canned status messages. This device (now
discontinued) was available as a kit from TAPR. Details here:
http://www.tapr.org/tapr/html/Fmic-e.html
The TigerTrak only sends Mic-E in the sense of 1) above; i.e. can be
triggered by PTT unkey on a voice channel. It DOES NOT send the
highly-compressed actual Mic-E format with super short bursts as in 2)
above -- it uses the standard plaintext (human-readable) APRS format.
I have a TigerTrak and have used it for a couple of years on HF
because it would do 300 baud, but always wished for a device that would
do the much shorter real Mic-E and smart beaconing which the TinyTrak
now offers...
Stephen H. Smith wa8lmf (at) aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff
http://members.aol.com/wa8lmf/aprs
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Subject: Re: Dayton APRS Events
From: James Smith <k9apr@sbcglobal.net>
Date: Sun, 15 Feb 2004 20:52:09 -0500
X-Message-Number: 18
Hi Jason, et all,
At this minute I haven't scheduled the APRS Pizza party as of yet.
Usually schedule it in mid march or so. But yes there will be a pizza
party at Dayton this year. I can't answer for TAPR but I'm sure John
(N8UR) can!!!!
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Subject: RE: New option for HF 30M APRS -- TinyTrak 3b (Review)
From: "Stephen H. Smith" <WA8LMF2@aol.com>
Date: Sun, 15 Feb 2004 17:55:35 -0800
X-Message-Number: 19
Scott Miller wrote on 2/15/2004, 11:20 AM:
>My biggest obstacle to implementing 300 baud is that I don't have anything
>to test it with. I have no HF equipment right now, except for a shortwave
>receiver. I'm not sure what the standards are, and I'd need a receiver to
>test with - haven't tried AGWPE yet. If someone wants to clue me in with
>the technical details I'll see what I can do. It should mostly just be a
>matter of changing some timing constants in the FSK code.
The only difference is that the data rate is at 300 baud instead of 1200
and that the two tones for the AFSK output are 200 Hz apart instead of
1200 Hz apart. There is no absolute tone standard as there is with
VHF-FM 1200 Hz since on HF-SSB, you can vary the actual frequency of the
recovered audio tones at the receiving end by tuning the SSB receiver a
few hundred Hz higher or lower. I would recommend using 1600/1800 Hz
in order to be consistent with the largest body of existing 300 baud
packet devices
A reprint of my previous posting on this issue follows below:
======== PASTE ======
Once again, a post on another APRS mailing list has indicated the
confusion and general cluelessness surrounding SSB frequencies and how
they relate to tones generated by packet devices on HF.
Simply quoting the RF "dial frequency" for HF data modes is ABSOLUTELY
MEANINGLESS unless you qualify it with the AUDIO tone freqs being used
by the TNC or other device.
The indicated "dial frequency" on SSB is the suppressed carrier
frequency. The supressed carrier frequency is NOT transmitted. What IS
transmitted are sidebands that are offset below the carrier freq on LSB
(or above the carrier on USB) by the exact value of the AUDIO tones fed
into the radio from the TNC, soundcard, modem, etc.
Since the actual transmitted RF frequencies (on lower side band) are the
indicated suppressed carrier frequency (i.e. "dial frequency") minus the
audio tone frequencies, the actual dial frequency you want WILL DEPEND
ON THE PARTICULAR AUDIO TONE FREQS your TNC or other device produces.
IMPORTANT! -----> Unlike 1200 baud VHF packet, there is NO SINGLE
STANDARD for the tone frequencies used by various devices on 300
baud/200-Hz shift HF packet! <-----
Frequencies Devices using them
1600/1800 Hz Kantronics KAM, TAPR TNC2 (MFJ 127x. etc), TinyTrak
2130/2230 Hz AEA/Timewave PK-232
1100/1300 Hz TigerTronics TigerTrak (300 baud HF mode)
2100/2300 Hz AGW Packet Engine softmodem (300 baud mode)
This is really not a problem on SSB since (unlike FM) you can always
change the recovered audio frequencies at the receiving end by tuning
the receiver a little higher or lower.
[ This cuts both ways. If the transmitter is off frequency, the tones
recovered at the receiving end will be correspondingly off-frequency.
Since the typical TNC or soundcard softmodem (i.e. AGW Packet Engine or
MixW in packet mode) will ignore any audio tones that are more than
about 20-30 Hz off, frequency setting is --VERY-- critical and high
frequency stability is essential. You MUST be able to set the frequency
to within 10 Hz and KEEP IT THERE indefinitely. This is especially
critical if you are going to transmit in the blind without a signal to
tune in on receive first! Ideally you want a modern synthesized rig
with a TCXO high-stabilty master oscillator. ]
The ==ONLY== constants are the ACTUAL RF freqs of the 200 Hz shift mark
and space tones on 30M APRS. They are:
10.149.200
10.149.400
To produce the correct RF frequencies with a KAM, TNC2 or TinyTrak (300
Baud HF mode) whose default audio tones are 1600/1800 Hz, you must set
your radio to
10.151.00 LSB:
10.151.000 - 1.800 = 10.149.200
10.151.000 - 1.600 = 10.149.400
Or set the radio to 10.147.60 USB:
10.147.600 + 1.600 = 10.149.200
10.147.600 + 1.800 = 10.149.400
To produce the correct RF frequencies with a PK232 whose default audio
tones are 2110/2310 you must set your radio to
10.151.51 LSB:
10.151.510 - 2.310 = 10.149.200
10.151.510 - 2.110 = 10.149.400
Or set the radio to 10.147.09 USB:
10.147.090 + 2.110 = 10.149.200
10.147.090 + 2.310 = 10.149.400
To produce the correct RF frequencies with a TigerTrak whose 300
Baud/narrow shift audio tones are 1100/1300 (weird pairing centered
around the 1200 Hz low tone for 1200 baud packet -- but actually very
nice because the tone pairs are in the dead center of the typical SSB
filter bandpass and suffer the absolutely least amount of phase and
group delay distortion) you must set your radio to
10.150.50 LSB:
10.150.500 - 1.300 = 10.149.200
10.150.500 - 1.100 = 10.149.400
Or set the radio to 10.148.10 USB:
10.148.100 + 1.100 = 10.149.200
10.148.100 + 1.300 = 10.149.400
To produce the correct RF frequencies with the AGW Packet Engine
softmodem, whose default audio tones on 300 baud HF are 2100/2300 you
must set your radio to
10.151.50 LSB:
10.151.500 - 2.300 = 10.149.200
10.151.500 - 2.100 = 10.149.400
Or set the radio to 10.147.00 USB:
10.147.100 + 2.100 = 10.149.200
10.147.100 + 2.300 = 10.149.400
Note that some HF radios with "DATA" or "FSK" modes offset the indicated
dial frequency to correct for the difference between the suppressed
carrier freq and the actual mark frequency, typically assuming the lower
tone is 2125 Hz (or sometimes 1800 Hz). This will force you to compute
offsets different from what I have listed for LSB/USB.
AGAIN: Quoting "dial frequency" alone is ABSOLUTELY MEANINGLESS unless
you qualify it with mode (USB/LSB/DATA, etc) and the AUDIO tone freqs in
question.
Stephen H. Smith wa8lmf @ aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff
http://members.aol.com/wa8lmf/aprs
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