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ZL3AI > APRDIG 11.10.03 10:04l 233 Lines 9305 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Oct 08, 4/5
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: varying the coverage of a RELAY
From: Bob Bruninga <bruninga@usna.edu>
Date: Wed, 8 Oct 2003 11:23:18 -0400 (EDT)
X-Message-Number: 16
On Wed, 8 Oct 2003, Wes Johnston wrote:
>...in a nutshell, our problem is that we have overlapping coverage
>between relay stations. 30% of our area overlaps, but 70% does not...
>and that 70% is important to us.
>
>What we need is to listen on a yagi, and TX on a 1/4 whip.
I like this thinking. But an even simpler approach is to simply take an
aluminum pole and mount it about 1/4 wave from the RELAY's vertical in the
offending direction. The resulting cardiod pattern will tend to null out
signals in the bad area, while still giving perfect coverage in the other
70%.. And its just a pole...
>the relay in to swap antennas in addition to keying the radio. Then he
>suggested we use a spare set of contacts on the relay to actually trigger
>the PTT on the radio.... cascaded PTT line.. the Radio can't key up until
>the relay is in the TX position.
>
>TNC PTT -> relay (coax and spare contacts)-> RADIO PTT
Too much complexity when a piece of aluminum might do the trick...
de WB4APR, bob
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Subject: Re: High Speed APRS
From: David VanHorn <dvanhorn@cedar.net>
Date: Wed, 08 Oct 2003 10:34:54 -0500
X-Message-Number: 17
At 03:49 PM 10/8/2003 +0600, Leon S. Ciereszko III wrote:
>Greetings to the group,
>I am installing a D700A in my work vehicle but have a small problem. It is
>a rental so I cannot drill any holes but need to be able to withstand
>sustained speeds of 160 kph(100mph) wit occasional speeds of 200kph(125mph).
>I don't think that a mag mount will cut it, but perhaps a lip mount? The
>vehicle is a hatch back. You got to love the German Autobahn!
Glassmounts?
I'm using larsen glassmounts now, for APRS and SSTV, with reasonable
performance. I've had airspeeds that high certainly.
You might get one of those big triple mag mounts, but man that's UUUGLY.
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Subject: Re: Abusive User paths
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 8 Oct 2003 08:46:53 -0700
X-Message-Number: 18
>Since we can't reverse engineer KPC software (and they are unlikely to
>issue a fix for kpc3 which is obsolete), what if we unplugged the
>microprocessor and installed a daughterboard with an AVR or PIC on it. Or
And be left with what, a TCM3105 and a few LEDs? Might as well throw out
the whole thing and start with a totally free design. And we still can't
compete with commodity hardware, at least not in price/performance ratio.
Got my net4501 board yesterday - the standard case is a sort of putrid
greenish beige, but the system itself is pretty cool. Just need to get a
Linux distro installed on the Compactflash card. I've been using a 16 meg
card, but Costco has larger cards cheap - I'll probably go with a 128 or 256
just to have room for compilation tools and such.
Scott
N1VG
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Subject: Re: Dwait Hacks kill APRS
From: Bob Bruninga <bruninga@usna.edu>
Date: Wed, 8 Oct 2003 13:31:40 -0400 (EDT)
X-Message-Number: 19
Those that believe that setting Dwait at the DIGIs to other than 0 or
hacking around with the UIDWAIT parameter in our APRS system are simply
dead wrong.
THe discussion to date only centered on its advantages in fratricide of
multiple dupes. But this discussion did not also mention the most
important aspect of these parameters even when there are NO dupes!
APRS is founded on flooding a packet outward to tiers of surrounding
digis. As has been shown, a 3 hop path can generate from 10 to 21 copies
of EVERY packet. WIth Dwait=0 and UIDWAIT OFF as is SUPPOSED to be, the
nominal propogation time for a 0ne-second packet will be 3 seconds.
But if local digi hacks have been messing with these parameters, so that
each digi tries to wait for the channel to clear before transmitting, then
the time period for ONE 3 hop packet to CLEAR the air can be from 10 to 21
seconds! With each person consuming that much air time, the local network
could only support about 3 users and 2 mobiles total!
Please, stop hacking your local digi, and get back to the original
settings at the digi. That is
1) DWAIT should be 0 (the default)
2) UIDWAIT should be OFF (the default)
3) The above two commands are the ONLY effect on digipeated UI packets in
Kantronics. But if you run any other FIRMWARE or ROM or software that
does not TRANSMIT IMMEDIATELY on a clear channel, then TURN THOSE OFF TOO.
The DIGI must transmit immediately (before any other users), and should
not use any process to avoid collision with other digis.
APRS was founded on the principle that packets are to radiate outward
efficiently from their source. And this includes all digis acting on the
same "hop" in a path to all digipeat at the SAME TIME. Sure, the carrier
detect from hidden transmitters makes this less than perfect, but it is by
far better than having every one of the 21 to 196 digipeaters all waiting
their turn to COPY the same packet.
de WB4APR, Bob
All Digipeaters in the APRS system that HEAR the same original packet are
all supposed to key up at the same time. This is supposed to
1) Kill any dupes by fratricide
2) Make all outward copies propogate at the same time so that the channel
clears quickly.
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Subject: TExt messaging to Sprint Phones
From: Bob Bruninga <bruninga@usna.edu>
Date: Wed, 8 Oct 2003 14:17:32 -0400 (EDT)
X-Message-Number: 20
I see that receiving text messages are FREE on the Virgin Phones (prepaid
phones). Has anyone figured out how to send APRS (or any Ham radio
application) data to them?
Bob
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Subject: Radio Shack GPS to D700
From: "Sadowski, Allan" <allan.sadowski@ncshp.org>
Date: Wed, 8 Oct 2003 14:31:50 -0400
X-Message-Number: 21
Dumb Question... but anyone here know the correct pinout to the RadShack
GPS to the 2.5mm GPS input to the D700 ??? i.e. what conductor on the
6 conductor RJ11 goes to what part of the 2.5mm jack on the D700.
Any advice on soldering a CAT5 cable to that *^#&%^ tiny 2.5mm three
conductor jack that Kenwood in their infinite wisdom used as the GPS
input???
What a pain for a shakey handed old man with lousy eyesight... I'm going
to burn my nose for sure ... having to get my face so close to the part
to solder it.... I'll probably melt the blasted connector AND burn my
nose...
ALOHA
AH6LS
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Subject: Re: Radio Shack GPS to D700
From: Dale Blanchard <wa7ixk@arrl.net>
Date: Wed, 08 Oct 2003 11:56:59 -0700
X-Message-Number: 22
Sadowski, Allan wrote:
>Any advice on soldering a CAT5 cable to that *^#&%^ tiny 2.5mm three conductor
jack that Kenwood in their infinite wisdom used as the GPS input???
I buy the cheap cable with the molded on plug, cut them into and splice
to the other cable ot puut a fitting on that end. I am just going to
crimp the phone plug on the end on the 2.5 mm cable.
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Subject: Re: 9600 user data - Digi_Ned 3rd Party
From: "Bill Vodall - WA7NWP" <wa7nwp@jnos.org>
Date: Wed, 8 Oct 2003 12:53:30 -0700
X-Message-Number: 23
>>>How do I get all those stations onto 70cm at 9600? Is there some app which
>>>will take rx'ed IGATE traffic and put it on the air direct (ie not as
>>3rd party packets with my callsign).
>>
>>Digi_Ned works great for that. It doesn't do 3rd party which is an option
>>that needs to be added.
>
>Can you be more specific so I know what I have to add?
>
>Is it converting incomming data from an IGATE link to third-party format?
>Isn't the IGATE supposed to do this when it converts the IGATE data back to
>AX.25 packets?
The IGATE does that and that's exactly what we need Digi_Ned to do. The
situation is where it's used to gate packets to an alternative network.
For some time I was using Digi_Ned to share the stations I heard on 10 MHz
out the local two meter channel. Not much additional traffic and it
livened things up a bit.
The concern I discovered was that then all the local Igates started to
think these 10 MHz stations were locals. If anybody sent them a message,
the Igates would pick it up from the Internet and transmit the messages
locally on two meters. Not a common occurance but some additional traffic
that wasn't needed. If I had used 3rd party format, the interesting
information would still be visible to the locals, but the stations wouldn't
be showing up as locals to the Igates.
This will also prevent the extra packets from getting fed to the APRS-IS
from multiple sources.
The same applies to using high speed alternative networks for local APRS
traffic. It would be good to see the local traffic from other nets but yet
not see them as "locals" on the alternate network. Smart handling of
messages here is a concern but I'll save that for another day.
73,
Bill - WA7NWP
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