[aprssig] Newbie Question

Scott Johnson kd5mhm at kd5mhm.org
Mon Jun 6 20:43:58 CDT 2005

There are a lot of "good things" for considering when looking at a TM-D700

1.  Dual band (dual vfo) operation allows me to have the benefits that some
of my friends don't with their dual-band radio.  I can simultaneously
operate in both bands, running APRS on VHF and phone (voice) on UHF.  this
has come in very handy many times.  Other brands also offer this dual-band
dual-vfo stuff, but no TNC.  However some of my friends can only operate
their "dual bander" in one band at a time, but not both (I didn't know this
when I got my Kenwood).  Some of my friends have two radios, one VHF and
another UHF.  While single-band radio prices are less, two of them rapidly
approach the cost of the Kenwood, especially once one factors in dual coax
and antenna costs vs a single dual-band antenna.   I was surprised to learn
that all "dual-banders" are not created equal...

2.  Cross-band repeater function.  One can use a 'cheapy hand-held' in low
power to hit the 'D700 and let it x-band repeat at higher power.  Complaints
about muddy audio (perhaps only in older units) are fixed by a single
capacitor change making it a clean sounding repeater.

3.  Single radio + TNC vs 2 radios + TNC vs dual-bander + TNC vs Kenwood
Costs.  When I originally priced up a system to let me have dual-band
(dual-vfo) operation, and the cost of a nice Kantronics TNC I found that I
matched or exceeded the price of the D700.  While prices might have changed
a little since then, I suspect that things are still pretty comparable
today.  This means that one can have a single radio-sized unit rather than a
radio+tnc cluttering up the car.

4.  APRS without the Laptop expense.  I often use the Kenwood without a
laptop, and do the messaging to people with only the DTMF mic of my Kenwood.
I recv messages (and at least in my area, NWS weather messages about
flooding, tstorms and tornados) right there on my Kenwood display.  I don't
'have' to have a laptop connected at all for any of this.  When I use my
Kantronics or MFJ TNC devices, I "have" to drag along a laptop (power
supply, etc) to clutter up the vehicle.  Having APRS built into the rig has
been a big plus more than once (and I was weaned on APRS with a laptop, so I
was very predisposed to that was the "only way" to do APRS until I got my
Kenwood and it convinced me otherwise).

5.  Digipeater function.  I have used this during ARES practice drills as an
emergency digipeater with good success.  Saves you the cost of another
radio+TNC to be set up as a digipeater (perhaps in your future).

6.  I'm going from memory now, but I think I recall that it also is "digital
ready" by having a data connection on the back (I could be wrong).  This
means that the "taps" into the audio circuits are in the proper place to
work with external TNC's, DSP's, etc.  Finding these points to "tap" in
other radios can be difficult for some owners, and can lead to problems when
using them with an external TNC...  (Somebody will let me know if I'm wrong,
I'm sure.  <grin>)

All-in-all, I discovered that there is a wealth of fine features in the
'D700.  I've used mine for satellite communications, bounced signals off the
Space Station, played APRS, enjoyed 1200 & 9600 baud packet radio,
experimented with emergency cross-band repeater and emergency digipeater
functions and also enjoyed Slow-scan-TV with my Kenwood VC-H1.  Most of my
friends have had to use multiple radios, TNC's, Laptops with SSTV
interfaces, etc to match what I can do with it.  (Color me 'happy')

Of course, Bob Bruninga has a ton of experience with the radio and probably
has dozens more things that can easily justify the small additional cost.

Although I've helped friends set up their radios and TNCs and all, I want my
Kenwood.  With it I've been able to do everything they've been able to do
except one thing.  I can't (yet) change the firmware to teach the TNC new
tricks, while they can unplug a memory rom and replace it...  As a
programmer, that is my one big gripe...  Of course, those program roms cost
something like $80 or so, so perhaps Kenwood is really saving me money in
the long run.  I'm sure I would have bought several rom upgrades for my
other TNC's if I didn't have the 'D700!  <grin>

Bottom line?  My bottom line got off a lot cheaper when I considered all
that I could do with it compared to buying a comparable system of radio(s)
and TNC and laptop, etc to get a true orange-to-orange comparison of
features.  Of course, I could argue the other way if you wanted <grin>!

Hope that helps (note:  no affiliation to Kenwood, have had my 'D7 and 'D700
for 5 years)

----- Original Message ----- 
From: "Christopher Long" <calgoofer at yahoo.com>
To: <aprssig at lists.tapr.org>
Sent: Monday, June 06, 2005 5:37 PM
Subject: [aprssig] Newbie Question

> I'm about to
> buy my first mobile rig
>.What practical uses can I use to
> win over my wife?
> Thanks in advance for your input.
> Chris

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