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ZL3AI  > APRDIG   19.06.04 22:20l 266 Lines 9143 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Jun 14, 2/2
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From: ZL3AI@ZL3VML.#80.NZL.OC
To  : APRDIG@WW

Subject: RE: UI-Network, not on 2m?  Yeah, and monkeys might fly outta.... (was
Trains, planes, and APRS)
From: Drew Baxter <droobie@maine.rr.com>
Date: Mon, 14 Jun 2004 19:01:42 -0400
X-Message-Number: 31

I hear the D700 holds the channel open nearly as long as a 1200bps packet, 
so the payoff is really not worthwhile with the Tasco TNC based devices 
(DR-135TP, D7, D700, etc).

I haven't tried it though.

--Droo, K1XVM

At 05:49 PM 6/14/2004, Eric H. Christensen wrote:
>David, the D700 mobile works on 9.6k as well as 1.2k.  I haven't really used
>it on 9.6k, though.  Heard it works well, too.
>
>Eric KF4OTN

----------------------------------------------------------------------

Subject: Re: waterproof/underwater APRS
From: "Robert Donnell" <kd7nm@pugetsound.net>
Date: Mon, 14 Jun 2004 16:18:37 -0700
X-Message-Number: 32

Hi All,

Regarding the antenna,

You'd get a lot better performance (unless you're going to use the coax
feed as a fore-stay) if you used an end-fed dipole.  The matching network
tuning is critical, and needs to be done with an SWR bridge or better, but
once done and sealed up in RTV and heat shrink, it'd be OK.  I'd use coax
with a Teflon center insulator and jacket, like RG-400 or RG-188, if
there's any possibility of moisture intrusion, because that material is
much more resistant to degradation from moisture than the more common
dielectric materials.  An off the shelf (if you can find 'em) end-fed
dipole is the AEA HotRod antenna.

The problem is that having the shield of the coax running next to one side
of the driven element of the dipole will really screw up the
radiation/reception pattern.

Hope that helps!

73, Bob, KD7NM

----------------------------------------------------------------------

Subject: RE: UI-Network, not on 2m?  Yeah, and monkeys might fly outta.... (was
Trains, planes, and APRS)
From: "Eric H. Christensen" <kf4otn@earthlink.net>
Date: Mon, 14 Jun 2004 19:07:48 -0400
X-Message-Number: 33

This is true!  However that isn't just with Kenwoods but with ALL
synthesized radios...

73s,
Eric KF4OTN
kf4otn@amsat.org

-----Original Message-----
From: Drew Baxter [mailto:droobie@maine.rr.com] 

I hear the D700 holds the channel open nearly as long as a 1200bps packet, 
so the payoff is really not worthwhile with the Tasco TNC based devices 
(DR-135TP, D7, D700, etc).

I haven't tried it though.

--Droo, K1XVM

----------------------------------------------------------------------

Subject: Re: UI-Network, not on 2m?
From: "WA8LMF@aol.com" <WA8LMF2@aol.com>
Date: Mon, 14 Jun 2004 16:30:12 -0700
X-Message-Number: 34

David Rush wrote on 6/14/2004, 12:36 PM:

>Are there issues with mobile 9.6k, any more so than with fixed stations?

YES!

1)  You can't just stick it in the mic jack like 1200. You have to make 
direct connections to the RX discriminator and TX modulator (usually DC 
coupled).  This virtually rules out trackers built with hand helds, or 
older mobiles without the dedicated "packet" or "data" input connectors.

2)  The higher data rate is FAR more suceptible to multipath, phase 
distortion and noise than 1200.  You need to have 5-10 times the signal 
strength for it to work reliably compared to 1200, meaning the usable 
range for the same antenna and TX power will be far less than 1200.  [ 
The typical fixed station <--> fixed  station link with better, often 
directional, antennas at each end of the path will experience a far 
higher and more constant signal strength than the typical mobile <--> 
fixed  link. ]

----------------------------------------------------------------------

Subject: Preemphasis circuit WAS: UI-Network, not on 2m?
From: "Scott Miller" <scott@3xf.com>
Date: Mon, 14 Jun 2004 17:35:19 -0700
X-Message-Number: 35

>1)  You can't just stick it in the mic jack like 1200. You have to make
>direct connections to the RX discriminator and TX modulator (usually DC
>coupled).  This virtually rules out trackers built with hand helds, or
>older mobiles without the dedicated "packet" or "data" input connectors.

Hey, speaking of which... I'm still working on my OpenTracker board for the
Kenwood Series 90 commercial radios.  I finally got ahold of the service
manual, and sure enough, the data audio in on the accessory connector isn't
pre-emphasized.

Since I'm going to be (usually) receiving it with a de-emphasized receiver,
and most decoders don't appreciate negative twist, I'm looking at adding my
own pre-emphasis.  Is there any (simple) accepted way to do this?  At this
point I'm just thinking of using an RC high-pass filter.

I could probably do it all in firmware, but that'd probably mean some
envelope scaling stuff that's not going to be fun to squeeze in the very
timing-constrained modulator code.

Has anyone run any tests to see how well AGWPE handles twist?

Scott
N1VG

----------------------------------------------------------------------

Subject: Bill Nolle
From: Wes Johnston <wes@johnston.net>
Date: Mon, 14 Jun 2004 22:11:26 -0400
X-Message-Number: 36

Anyone heard from wa8inz lately?
Wes

----------------------------------------------------------------------

Subject: wIDE2-2 instead of WIDE2-2
From: Curt Mills <archer@eskimo.com>
Date: Mon, 14 Jun 2004 19:29:36 -0700 (PDT)
X-Message-Number: 37


Anyone know why the "wIDE" is getting in here?

N4YLC-1>APT311,W6CX-3*,wIDE2-2,qAR,AA6VN-5:/230323h3746.27N/12223.84Wk349/042/A0
=00052/soldering fun!

N4YLC-1 looks to be using a Tinytrak-3.

AA6VN-5 is an Xastir client and is injecting the packets with a ",I"
construct ("qAR,AA6VN-5" tells us this).

So...  Who's converting the "WIDE2-2" to "wIDE2-2"?  It has to be at
the injection point or between there and findu, as lower-case
letters in the AX.25 header are impossible.  They can't occur on RF.

N4YLC-1 is not seeing his tracker packets on his Xastir client which
is hooked to the internet.  The 'w' kicks it out in the valid_path()
function.  It may be a bug in the Xastir igating, but I don't recall
seeing it before, and it seems likely it would have happened more
often by now.

Any ideas on where to look further?  I'm scanning the internet feed
for "wIDE" right now to see if I can find which stations are doing
this.

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"

----------------------------------------------------------------------

Subject: RE: wIDE2-2 instead of WIDE2-2
From: "Scott Miller" <scott@3xf.com>
Date: Mon, 14 Jun 2004 19:53:22 -0700
X-Message-Number: 38

>So...  Who's converting the "WIDE2-2" to "wIDE2-2"?  It has to be at
>the injection point or between there and findu, as lower-case
>letters in the AX.25 header are impossible.  They can't occur on RF.

Not true.  The spec states that they SHOULD only use upper-case letters.
It's not a good idea, but it's not physically impossible.  I just modified a
packet in a binary editor and tested it out:

local: fm N1VG to oPNTRK via WIDE ctl UI^ pid=77(OPENTRAC) len 56

So don't go ruling out an on-air problem completely.

And before anyone starts screaming about invalid traffic, please note that
the above was only sent to a loopback port!  =]

Scott
N1VG

----------------------------------------------------------------------

Subject: RE: wIDE2-2 instead of WIDE2-2
From: Curt Mills <archer@eskimo.com>
Date: Mon, 14 Jun 2004 20:04:14 -0700 (PDT)
X-Message-Number: 39

On Mon, 14 Jun 2004, Scott Miller wrote:

>>So...  Who's converting the "WIDE2-2" to "wIDE2-2"?  It has to be at
>>the injection point or between there and findu, as lower-case
>>letters in the AX.25 header are impossible.  They can't occur on RF.
>
>Not true.  The spec states that they SHOULD only use upper-case letters.
>It's not a good idea, but it's not physically impossible.  I just modified a
>packet in a binary editor and tested it out:
>
>local: fm N1VG to oPNTRK via WIDE ctl UI^ pid=77(OPENTRAC) len 56

Ok.  Been a while since I was that deep into that particular spec,
so I appreciate that.

It sounds then like the person may have typed the path into the
Tinytrack-3 config program incorrectly.  I'll investigate that.
Thanks!

-- 
Curt, WE7U.				archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"

----------------------------------------------------------------------

Subject: RE: wIDE2-2 instead of WIDE2-2
From: "Scott Miller" <scott@3xf.com>
Date: Mon, 14 Jun 2004 20:17:17 -0700
X-Message-Number: 40

>It sounds then like the person may have typed the path into the
>Tinytrack-3 config program incorrectly.  I'll investigate that.
>Thanks!

I just checked my copy of the TT3 config program and it won't accept lower
case, even when pasted in.  A single bit error during programming might
cause that, though.

Scott
N1VG

---

END OF DIGEST



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