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Initial Impressions of the Icom IC-706

Subject: Initial Impressions of the Icom IC-706
From: AA6KX@aol.com (AA6KX@aol.com)
Date: Sat Dec 23 23:07:55 1995
Note:  The following is an article I started to write for the NCCC
newsletter, but then I decided not to submit it and consequently never
finished the article.  This doesn't address the questions K7SS posed about
the suitability of the 706 as a contest radio, but there may be some
information here some of you may find useful.

Most people react to the new IC-706 with statements like ?That sure is a cute
little rig.?  It is extremely compact (6-9/16? x 2-9/32? x 7-7/8?) and
lightweight (5.5 lb) for a full-featured rig, so it?s not surprising that the
word which first comes to mind is ?cute?.  I think the design of this rig
goes way beyond ?cute?.  I would call it ?ingenious?.

The eight days I spent driving to and from Whitehorse for SS definitely
hooked me on mobile operating.  I had no idea you could do so much with a
simple mobile whip until I tried it.  More than that, it was comforting to
know I was still in touch while going through the long empty stretches of the
Yukon wilderness.  At the same time, though, I gained a good appreciation of
the shortcomings of a typical base station rig for mobile operations.  My
FT-990 has a clean, uncluttered panel layout.  Part of the reason I selected
it was that I estimated that uncluttered layout would still be usable after
47 hours of without sleep.  But on the Yukon trip I learned that the 990 is
easy to use only if you can look at it for more than a second or two.  When
you?re trying to watch the road while driving, this just is not possible.
 The panel of the 990 then becomes a nightmare to navigate by feel and sound.
 The IC-706 distinctly addresses this problem; it has been designed
specifically for mobile operation.

First, though, some simple facts about this tiny little rig.  It has receive
capability from 300kHz through 200 Mhz.  For the entire range, it can do AM,
FM, wideband FM, USB/LSB, CW, and RTTY.  It transmits on all of the amateur
bands in this range in all modes.  Power output is variable, up to 100 W on
160 - 6 meters and up to 10 W on 2 meters.  (On AM, though, max power output
is 40 watts on 160 - 6 and 4 W on 2.)  The front panel, which is only 1-3/4?
deep, can be separated from the rest of the unit and connected to it by a
single cable.  Thus the base unit can be placed in the trunk of your car and
the panel mounted in place of the standard AM/FM radio in your car.  It does
a fine job on the AM and FM broadcast bands and there are 99 memories that
can be programmed just like your car radio.  To the unobservant, this is
exactly a replacement for the car radio.  Except, of course, for the fact
that it is also a full-function HF and 6 meter and 2 meter rig!

The front panel supports only two connections:  microphone and headphones or
speakers.  If you want to place the base unit in the trunk as mentioned above
and still do CW, then you will need to run a separate cable for the paddle.
 The base unit has connectors for power, an external speaker, computer
control (unfortunately, at TTL levels), one HF antenna and one 2 meter
antenna, ground, RTTY (FSK), plus a second microphone connection.  There is
an accessory connector which offers several important signal lines (e.g. band
data, up to 1A of 13.8 V, amp relay).  Connections are provided for hooking
up an external automatic antenna tuner. 

If all of this makes it sound like the 706 complete base station rig, a few
caveats are in order.  Filter selection is limited, for starters.  You can
install one 1900 Hz SSB filter or one 500 Hz CW filter or one 250 Hz CW
filter.  That?s it.  With no filters installed the passband is 2300 Hz.
 That?s fine for SSB operation, but surely not for CW.  This really reduces
to operating with a 2300 Hz SSB passband and either 500 Hz or 250 Hz on CW.
 There is no provision for a receive antenna, so beverages are simply out.
 (This was designed as a mobile rig, remember?)  There is no internal antenna
tuner, but Icom does offer a couple of automatic external ATs.  Either of
these can be placed in the trunk, close to the antenna, and it looks to me
like the external AT is an elegant, though expensive, solution.  One other
minor limitation I noted is that the unit does not have a DTMF encoder for 2

With these limitations, the rig does have just about every other feature you
would expect to find in a base station rig:  fast or slow AGC, an internal CW
keyer, a noise blanker, 99 memories together with all of the scanning
capabilities most modern rigs offer, a set of scratch pad memories, full
metering capabilities (S meter, power output, microphone gain, and SWR), a
speech processor, variable CW pitch, RIT, a preamp, an attenuator, IF shift,
etc., etc.  There?s even a front panel spectrum analyzer which somewhat
resembles the IC-781 display.  What?s most amazing is that all of these
capabilities are offered with a front panel containing only 14 buttons and 3
knobs.  All can be located easily by feel.  Audible feedback abounds as you
operate the controls in order to reduce the necessity of actually looking at
the panel.

Operation of the rig is really quite simple, though it is not obvious on
first encounter.  You really need a few hours with the rig and the manual in
order to learn how to access the different functions.  The rig is essentially
menu-driven, and the menus are divided into 5 different groups.  The first
group, which I?ll call the initialization functions, is selected when you
power up the rig while holding down the VFO lock button.  This group allows
you to set configuration options which rarely change (e.g. panel lighting
brightness, FM duplex offset, scanning speed).  The second group, the ?Q?
(quick set) group, contains settings which change infrequently.  Hold the
?DISP? button for two seconds and you enter this group, then cycle through
the 6 different functions with the ?MEMO? button.  It is here, for instance,
that you will set the CW keyer speed, the power output, the mic gain, etc.
 The other three menu groups are called ?M? (memory), ?S? (scan), and ?G?
(graphics).  The ?DISP? button cycles you from one group to the next, and
within each group the ?MEMO? button will cycle you around the options in the
group.  For any of the menus, there are three buttons (labeled ?F-1?, ?F-2?,
and ?F-3?) which are used to select options, toggle values, or perform
functions.  For example, you turn on the noise blanker by pressing ?DISP?
until you get to the ?M? group, then press ?MEMO? until you get the M3 menu.
 That menu labels the F-1 button as ?NAR? (select narrow filter), F-2 as ?NB?
(select noise blanker), and F-3 as ?MET? (select metering option).  If all
this sounds complicated, it really is not.  But it does take some practice to
feel comfortable with it.

So what exactly makes this rig so good for mobile operations besides its
compactness?  I think it?s all the little touches.  When you tune through a
band edge the rig beeps at you.  This might sound silly when you?re thinking
of a base station rig, but for mobiling it is very, very convenient.  You
don?t have to keep watching the dial to know when you?ve tuned off the top
end of the band.  Every button can be located by feel, and only a brief
glance will tell you which menu is currently up.  Once you get used to the
rig, you then know how many times to press which button to get to which other
menu you want, and then you can locate the function buttons by feel.  I can?t
count the number of times I lost a contact on my Yukon trip, in contrast,
when I hit the ?scan start? button when I was trying to clear the RIT.

In terms of on-the-air experience with the rig, I haven?t really had a chance
to put it to much of a test yet.  I have received good reports back on the
audio using the default hand mic that comes with the rig, but that?s probably
not saying a whole lot.  I did get a very critical ear (W6CYX, who is a
FOCer) to listen to the CW waveform for me, and he said it sounded just
perfect to him.  Probably the most significant test I did was to set it up to
use the same speaker (an Icom SP-20) and the same antenna setup and do some
side-by-side comparisons with my FT-990.  In terms of noise floor and
sensitivity, the two sounded nearly equivalent.  The audio in the 706 doesn?t
have as much bass response, and probably would sound absolutely tinny in a
side-by-side comparison with a TS-870.  It?s only a dual-conversion receiver,
so it would be a real surprise to me if it performed as well as a true
contest radio.   However, the casual testing I?ve done so far doesn?t show it
to have much of a disadvantage relative to my 990.  It drives the Alpha quite
nicely, thank you!

In summary, this rig was designed for a specialized niche market:  mobiling.
 It does just about everything you?re likely to want in one extremely compact
package.  Secondarily, it is excellent as a traveling companion.  I?ve
discovered that I can fit both the rig and a laptop computer in a standard
size briefcase and still have enough room left over for mic, paddle, and
headphones.   Now if I could just find a way to pack a tower I?d never have
to do another contest from California again!   

>From n3rr@cais.cais.com (Bill Hider)  Sun Dec 24 08:21:33 1995
From: n3rr@cais.cais.com (Bill Hider) (Bill Hider)
Subject: W6QHS 40-2CD mods bibliography
Message-ID: <199512240821.DAA07950@cais.cais.com>

>To: Steven Affens <k3sa@access.digex.net>;cq-contest@tgv.com
>From: n3rr@cais.com (Bill Hider)
>Subject: W6QHS 40-2CD mods bibliography
>Steve, they were contained in a November 1991 QST article: Strengthing the
Cushcraft 40-2CD, pp 36-42.  
>A followup letter to editor and W6QHS response was in October 1992 QST pp
>Another article to read: Simplified Strengthing of the Cushcraft 40-2CD, by
N4KG, in NCJ MARCH/APRIL 1994, page 14.  That article is based on W6QHS'
article, too.
>Finally, Dave's book The Physical Design of Yagi Antennas, by Dave Leeson,
W6QHS, published by the ARRL, goes into the modifications as well, although
I think the QST article has much more detail and is easier to follow.
>At 09:35 AM 12/23/95 -0500, Steven Affens wrote:
>>If you have the detailed description of the W6QHS 40-2CD mods, please 
>>forward them to me. 
>>Steve K3SA
>>Steven C. Affens

>From Kurt Pauer <0006743923@mcimail.com>  Sun Dec 24 15:52:00 1995
From: Kurt Pauer <0006743923@mcimail.com> (Kurt Pauer)
Subject: Another 80/75M Vertical Antenna
Message-ID: <70951224155207/0006743923ND4EM@MCIMAIL.COM>

                   Cushcraft AV-80 for 80/75 meters
Another choice for an 80/75 meter vertical is the Cushcraft AV-80 which
is now in production.  I talked with an engineer at Cushcraft the other
day and came up with this information.  (This is from memory which is
subject to lapses in.)  
It is about 42 feet high, self-supporting, and 2 inches in diameter.
The antenna is a quarter wave resonant vertical and needs radials.
Top loading is achieved with a capacity hat of several (I think 4)
four foot loading rods similar to the ones on the bottom of the R7.
There is a relay box at the bottom of the antenna that switches some
small coils to achieve resonance over most of the band.  (I think it
was 3.5 to 3.95 mHz or so.)  The relay is energized through the feedline
with 12 VDC to give either 80 or 75 meters.  The coils can be adjusted
by spreading or compressing the turns to change the resonance points.
The street price is around $350.
I asked about on-the-air performance.  He had no CONTEST reports, but
one user (in the Carolinas) had reported excellent results and had
inquired about phasing two of them.  Cushcraft does not currently
have any recommendations on phasing them, but may look into the
possibility of a phasing box for a 4 Square array.  The engineer
was definitely non-committal on this point.
I hope this information may be of use to a CONTESTer.  
                              Kurt, W1PH

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