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ZL3AI > APRDIG 04.08.06 09:16l 262 Lines 10545 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 25 #31, 1/3
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To : APRDIG@WW
Today's Topics:
1. Re: Need help testing 30m HF APRS in the Northwest (J T)
2. Autoscaling on pressure graphs (Steve Dimse)
3. Re: Need help testing 30m HF APRS in the Northwest (James Smith)
4. Re: Need help testing 30m HF APRS in the Northwest (Ben Jackson)
5. Re: Need help testing 30m HF APRS in the Northwest (Stephen H. Smith)
6. Re: Need help testing 30m HF APRS in the Northwest (Ben Jackson)
7. Re: Need help testing 30m HF APRS in the Northwest (Glenn Wiebe)
8. Re: Need help testing 30m HF APRS in the Northwest (Ray McKnight)
9. Re: Need help testing 30m HF APRS in the Northwest (Ben Jackson)
10. Re: Need help testing 30m HF APRS in the Northwest (Stephen H. Smith)
11. Re: Need help testing 30m HF APRS in the Northwest (Robert Bruninga)
12. Re: Need help testing 30m HF APRS in the Northwest (Robert Bruninga)
13. Re: Need help testing 30m HF APRS in the Northwest (Robert Bruninga)
14. Looking for a manual/schematic (Stephen Brown Jr)
15. Re: Looking for a manual/schematic (jemllc_at_bellsouth.net)
16. Re: Looking for a manual/schematic (Rich Mulvey)
17. Re: Looking for a manual/schematic (James Smith)
18. Anyone know what DISABL is? (Patrick Green)
19. RE: Anyone know what DISABL is? (Edwards, Chris)
20. Re: Anyone know what DISABL is? (J T)
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Message: 1
Date: Sun, 30 Jul 2006 11:31:47 -0700 (PDT)
From: J T <w0jrt_at_yahoo.com>
Subject: Re: [aprssig] Need help testing 30m HF APRS in the Northwest
Robert Bruninga <bruninga_at_usna.edu> wrote:
>But the point is, It makes no sense to DIGIPEAT on HF. Please dont do it.
>The recommended path was always VIA GATE,WIDE and now that should be VIA
>GATE,WIDE1-1.
GATE,WIDE1-1 is like saying GATE,RELAY. Is that really what you intended?
Or would did you mean GATE,WIDE2-1?
-Jerome, W0JRT
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Message: 2
Date: Sun, 30 Jul 2006 14:51:04 -0400
From: Steve Dimse <steve_at_dimse.com>
Subject: [aprssig] Autoscaling on pressure graphs
findU now uses autoscaling for the barometric pressure graphs, e.g.
http://www.findu.com/cgi-bin/wxpage.cgi?call=K4HG&last=48
I've looked at a few dozen and all look good, but with thousands of
weather stations and hundreds of last-hours options for each, it is
obviously impossible to test for all possibilities. If you see
something that looks bad, please email me the URL.
Thanks,
Steve K4HG
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Message: 3
Date: Sun, 30 Jul 2006 19:19:44 -0400 (Eastern Standard Time)
From: "James Smith" <k9apr_at_tawg.org>
Subject: Re: [aprssig] Need help testing 30m HF APRS in the Northwest
A non-text attachment was scrubbed...
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Message: 4
Date: Sun, 30 Jul 2006 16:50:19 -0700
From: Ben Jackson <ben_at_ben.com>
Subject: Re: [aprssig] Need help testing 30m HF APRS in the Northwest
On Sun, Jul 30, 2006 at 07:19:44PM -0400, James Smith wrote:
>I agree with John on this one, 400mw how much damage can he cause. They're
>is only a hand full ops running HF Gateway's me included.
I didn't mean to create a path commotion. If WIDE2-2 is recommended for
fixed stations, then GATE,WIDE2-2 makes sense to me on HF. I'm sure there
will always be arguments, since source routing doesn't make much sense
for APRS, especially on HF. It's fine for fixed stations which can adjust
their path until they get the desired result. For mobile stations there
should really be a route like "get me on the internet!" and the first
fixed digi to hear the packet should just substitute a route known to
work in the local area.
Anyway, back to my original experiment: I've added a IRF510 final and
gone up to about 3wa and I'm still not showing up on findu, so if anyone
out there can coordinate with me to give me a quick signal report on
10.151 LSB, I'd appreciate it.
--
Ben Jackson AD7GD
http://www.ben.com/
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Message: 5
Date: Sun, 30 Jul 2006 21:18:11 -0400
From: "Stephen H. Smith" <wa8lmf2_at_aol.com>
Subject: Re: [aprssig] Need help testing 30m HF APRS in the Northwest
ben_at_ben.com wrote:
>
>Anyway, back to my original experiment: I've added a IRF510 final and
>gone up to about 3wa and I'm still not showing up on findu, so if anyone
>out there can coordinate with me to give me a quick signal report on
>10.151 LSB, I'd appreciate it.
10.151MHz is only the correct supressed carrier frequency if you are
running 1600/1800 Hz audio tones into a radio on LSB. If you are
running other audio tones ( or using direct FSK of a CW carrier ) to
generate the packet transmissions, then you are not on the correct
frequency.
The actual mark and space frequencies for 30M HF APRS are 10.149.2 and
10.149.4. What ever you do to generate the packet data must result in
these frequencies (+/- 20 hz or so) being the actual output of the
transmitter. Because of the very narrow receive passband of most TNCs
on 200 Hz shift on HF, you MUST be within 10-20 Hz absolute of the
correct frequency on transmit.
===== REPRINT of a previous post on this issue (HF APRS transmit frequencies).
Packet data transmission is done by rapidly shifting an audio tone
between two frequencies traditionally referred to as the "MARK" and
"SPACE" frequencies. On 1200baud VHF packet, these two tones are 1000
Hz apart and standardized on 1200 and 2200 Hz. On 300 baud HF, the two
tones are 200 Hz apart and ARE NOT STANDARDIZED.
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.
o The indicated "dial frequency" on SSB is the suppressed carrier
frequency.
o The supressed carrier frequency is NOT transmitted.
o 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 mic jack 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.
-----> NOTE THIS ESSENTIAL FACT!!! <-----
-----> Unlike 1200 baud VHF packet, there is no standard for the audio
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)
The differing AUDIO frequencies are really not a problem on SSB and are
easily accommodated. (Unlike FM the audio pitch heard at the receiving end
is affected by the exact frequency the transmitter and/or receiver is set
to.) You change the audio frequencies, as heard at the receiving end, by
tuning the transmitter to a slightly higher or lower "dial frequency".
This, of course, results in a slightly different indicated "dial
frequency".
[ 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
NOTE: The traditional ham convention is to specifiy the actual RF
frequencies of the two RF signals. The commercial/military/regulatory
convention is to specify the single frequency midway between the two
tones, along with the shift. In this format, the 30M APRS channel would
be quoted as:
"10.149.300 with +/- 100 Hz shift" or "200 Hz Shift Centered on
10.149.300".
To produce the correct RF frequencies with a KAM, TNC2 or TinyTrak III
(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 on non-FM modes is ABSOLUTELY
MEANINGLESS unless you qualify it with mode (USB/LSB/DATA, etc) and the
AUDIO tone freqs in question.
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