[aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!
noskosteve at yahoo.com
Sun Aug 7 08:10:42 CDT 2016
Ah! Sorry Stephen. I think I get it now. I scanned your post a little too quickly. (I'm in the last of an estate sale and feel rushed)
The difference showed up only with the bad cable/poor signals; but with a good cable/signals the D700 still performs well on the target route.
Therefore, the D700 will work for you, but you still saw the weak signal difference.
So, my comment still applies, but to the Amo-Can Tracker modulation being 'off'..
A) It could be that the SoundModem is more acceptable of 'off' modulation and performs better all around; a good thing for the SoundModem, shame on the D700.
B) It could be that the SoundModem's 'ear' is "off" the same way the Amo-Can is (if you know what I mean). This may mean that the SoundModem will be poorer on 'correct' modulation. Good for the D700, but shame on the SoundModem.
C) Nobody want to hear that the ole' D700 is inferrior... (:-o) Boo Hoo.
Cheers, Steve Noskowicz K9DCI
Science & Technical Advisor
On Sat, 8/6/16, Stephen H. Smith <wa8lmf2 at aol.com> wrote:
Subject: Re: [aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!
To: "Steve Noskowicz" <noskosteve at yahoo.com>, "TAPR APRS Mailing List" <aprssig at tapr.org>
Date: Saturday, August 6, 2016, 11:07 PM
On 8/6/2016 10:19 PM,
Steve Noskowicz via aprssig wrote:
Hold on. (I know Stephen is quite astute). However, Keep
in mind guys. This test also
on the signal transmitted from the digi. Set up the digi
differently and you can
>skew the data. Perhaps the digi is setup
There was no digi involved in
my test. I had the FT-1500/TT3 ammo-can
tracker, equipped with a Diamond 770
no-ground-plane half-wave whip, located at
the PROPOSED digi site, beaconing direct to my
mobile down below.
purpose was to evaluate whether the proposed digi location
cover the entire area I need
to cover with enough RF. This after playing with
terrain profiles in Delorme Topo North America
in my motel room the night
select a "magic location" to cover what amounts to
joined at right angles.
The discovery of how much
poorer the D700's internal TNC was than the
Soundmodem soft TNC was purely by accident.
On the first drive-test run,
the signals from the hill-top beacon to the mobile
on my selected route down below were very poor,
signals any time I was more than about a third-mile
from the transmitter. It was then that I was
surprised to see the Soundmodem
out-copying the D700 TNC on these noisy signals.
After wondering why I had so
little signal, I returned to the transmit site,
disassembled the ammo-can tracker, and
discovered that a coax cable assembly in
tracker box was defective (bad crimp in a commercially-made
resulting in extremely low
ERP. [Bench-testing the setup at home before
trip, I never had the tracker box more
than about 25 feet from my mobile so I
never realized I had 20+ dB loss on transmit!
Next time, this thing goes into a
and dummy load before hitting the field...]
I bypassed the bad cable, and
re-ran the test. This time I was getting "full
smash" completely-quieted signals around
the entire 4-mile loop test course.
signals were good enough that my even TH-D72 handheld lying
the seat INSIDE the car (no
external antenna - just a 19" whip) copied
virtually every transmission as well.
The result of these
investigations is that the difference in the receive
capabilities of the D700 hardware TNC and the
soft TNC will be insignificant in
actual application next year. (I have full-quieting signals
the loop with the
FT-1500's 40-50 watts out.)
Next year the "magic location" on the
hillside will be occupied by an "ammo-can
digi" containing another FT-1500 mated to
a KPC3+ and another Diamond 770
no-ground-plane whip. The current FT-1500/TT3 ammo box
be strapped to the shuttle
The 4 receive
locations for the digi's downlinks (one at each venue)
be Wouxun KG-UV8D handhelds with
19" whips, mated to the sound input of
Microcenter 7" "Winbook" tablets
running the Soundmodem and mapping software.
In turn the tablets will be Velcro'ed to
the back of 23" HDMI monitors (the
tablets have a full high-def 1080p HDMI
output) placed at the entrance of each
KG-UV8Ds come with a nice drop-in charger with built-in AC
standard equipment. (no wall wart
- just a lightweight 18/2 "shaver" cord) The
charger holds the radio very stably in a
vertical position, making for a very
compact and tidy receive setup.] I
actually took my TH-D72 inside each venue
during the drive test, to verify that I have
enough RF -INSIDE- each building
modest receive setup to work reliably.
Stephen H. Smith wa8lmf (at) aol.com
EchoLink: Node # 14400 [Think bottom of
the 2-meter band]
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