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ZL3AI > APRDIG 26.05.03 22:04l 166 Lines 5913 Bytes #999 (0) @ WW
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Subj: TAPR Digest, May 23, 5/5
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: mic-e muting
From: Wes Johnston <wes@johnston.net>
Date: 23 May 2003 14:31:03 -0400
X-Message-Number: 24
This may be of interest to some of you... or not.
I've just spoken with the cat1000 people today on the phone. They told
me that the cat1000 has either a 4k or 10k input impedance (depending on
the revision level) on the COR signal input pin. I discussed placing a
270ohm resistor in SERIES with the COR signal out of the radio and then
using the kpc3plus CTRL signal to shunt the CAT1000 end of the COR to
ground. This will allow the kpc3 to mute packets by "stealing" the COR
signal away from the repeater controller without having to use a (slow)
relay. Of course I may have to use a PNP transistor if the COR signal
is the wrong logic. The audio input to the repeater is not interrupted
ever... just tap off of it to get audio to your TNC.
Today I'm building a cat1000 TNC interface to insert between the db25
plug on teh back of the cat1000 and the radio plug. Radio shack part
number 276-1403a will be used as the basis for this "daisy chain"
insertion. This way we can insert and remove the TNC without changing
the wiring harness of the cat1000.
Wes
----------------------------------------------------------------------
Subject: GE master II
From: Wes Johnston <wes@johnston.net>
Date: 23 May 2003 15:42:08 -0400
X-Message-Number: 25
Can anyone tell me the COR logic levels for a GE master II ? Hi or Lo
on receive?
Wes
----------------------------------------------------------------------
Subject: Re: mic-e muting
From: WA8LMF2@aol.com
Date: Fri, 23 May 2003 16:25:53 EDT
X-Message-Number: 26
In a message dated 5/23/2003 11:34:47 AM Pacific Daylight Time,
wes@johnston.net writes:
>Of course I may have to use a PNP transistor if the COR signal
>is the wrong logic.
I've just been dealing with this very issue building sound interfaces with
COR input for EchoLink. The most painless approach yet that I've found to
this issue of COR/ logic-level sense inversion is to use 50-cent
opto-isolator chips.
Connect the input to the squelch line in series with a 1K to 3K resistor
depending on voltage present. On the NPN transistor output, connect the
collector to +V, the emitter to ground through a resistor, and the logic
input being driven to the junction between the iso and resistor (for
positive logic CMOS inputs). --OR-- Connect the opto's collector
directly to the logic input and the emitter directly to ground (for
TTL-level inputs with internal pullup resistors).
And you get total isolation between the chassis/ground systems of the two
devices.
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
----------------------------------------------------------------------
Subject: RE: APRS-NET COncept!
From: Bill Vodall - WA7NWP <wa7nwp@jnos.org>
Date: Fri, 23 May 2003 13:30:16 -0700 (PDT)
X-Message-Number: 27
>I prefer to take the approach in HAM radio to figure out a way to use
>what we have in hand, rather than to always wait and hope that someone
>will eventually manufacture exactly what I want.
I agree. We need to do both. We need to use what we have AND offer
constructive feedback to the manufactors on how to improve their equipment
so it'll be more useful (and we'll buy more.)
I predict that the next generation Radio Mirror will be using shorter
packets by the end of the summer... It will have a friendlier interface
to different Packet interfaces like SV2AGW much sooner.
73,
Bill - WA7NWP
----------------------------------------------------------------------
Subject: PCSAT2 (prototype) on AIR
From: Bob Bruninga <bruninga@usna.edu>
Date: Fri, 23 May 2003 17:18:48 -0400 (EDT)
X-Message-Number: 28
PCSAT2 prototype is on the air in Annapolis, Maryland (USA) and may be
workable out to about 10 miles. We invite anyone in range to
please experiment with its three transponders:
* APRS/UI digipeater (145.825 up and down)
* PSK-31 transponder (10m ssb up 435.250 down) (see note below)
* FM Voice repeater. (145.800 up 437.975 down)
See: http://web.usna.navy.mil/~bruninga/pcsat2.html
We need your help to test it thoroughly so we can fix any bugs now instead
of living with them later. Like PCsat, PCSAT2 has no control system other
that the basic KPC-9612+ TNC. Thus we used the CONNECT LED as the
simple means for USER control of the transponders. This way, anyone can
turn on a transponder and the connection-time-out process gives us an
automatic time out 8 minues later to save power when it is not in use.
NOTES ABOUT THIS TEST:
1) To provide some signals for the PSK-31, the HF uplink is not on 10m
but is being fed by an external 20m receiver listening to 14.070.
We do not expect you to try to transmit, but just have something to
RX..
2) TELEMETRY is running at 4 times the rate we will use on flight.
3) To give you something to do, we activated the PBBS. Its call is
PC2BBS. This is NOT normally going to be used on PCSAT2. But
is an easy way to test the packet system.
4) Next week, I will release a telemetry decoding and display program.
Again, see the web page above for details
de WB4APR, Bob
----------------------------------------------------------------------
Subject: Re: WinAPRS Crash
From: "Dick Stanich" <dick@kb7zva.com>
Date: Fri, 23 May 2003 21:18:2
X-Message-Number: 29
>Chris
>
>Thanks for the report, did you get any indication what crashed it? I
>have been connected to the second.aprs.net internet feed for almost
>12 days without a problem.
>
>Mark
Mark,
second.aprs.net had been up 7 days when you posted your message :)
Dick
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