ICOM IC-706MkIIG

Although this isn't intended to be a review of the radio, some comments would be in order to establish some groundwork as the rest of the page develops. 

Everyone certainly will have their own opinion about this little rig.  My first impression was that it was too small.  I still think so, however, I am finally getting used to the small size and having to change parameters via layered software menus and not discreet controls on the front panel.  Although a bit inconvenient, once you get used to the menus, you can maneuver quickly and change most parameters that would be located on the front panel on most larger ham rigs.  So far, performance has been excellent but that is based on my ears and not having another rig sitting next to it to compare it to.  Although on paper the receiver falls short of what you could call great, it does do the job.  The DSP could use some tweaking.  The DSP unit in the SG-2020ADSP was much better at reducing background noise without distorting the audio.  The notch filters seem to be comparable.  This radio has many features that until recently could only be found on performance rigs.  One of its better features is that the designers allowed for 2 optional filters. Unfortunately, no one makes filters for it but ICOM. There is also a TCXO option (CR-282) that makes the rig NTIA compliant on the HF bands. (Note that this is no longer true. Many radios that were compliant in the past are no longer including the RF-350K, not because of frequency stability, but IMD.) (Check the Database to see if your HF radio is NTIA compliant.) 

This rig is light years ahead of the SG-2020 for the same price.  The only advantage the SG-2020 has is lower current drain for portable use, but ICOM's IC-703 should beat it hands down for portable use.

INSTALLING THE CR-282 TCXO

This was actually a fairly painless mod except: don't attempt this if you are claustrophobic. If you are nervous working inside of TINY spaces, leave well enough alone.  Click here for information on performing the mod.  This info was very helpful in getting the job done whereas the operators manual didn't provide any help at all.  The only thing I would add is to clean the new solder pads with an ink eraser prior to soldering.  They are lacquer? coated and solder would NOT stick until clean.  Tune up was simple and there have been no problems noted so far.  Unfortunately, I have no way to comment on the actual stability improvement.

AM FILTER MOD

I read an article about improving the AM performance in the IIG by replacing the AM filter (FL-94) with the AM filter (FL-116) from the original 706.  I ordered the filter from ICOM (Total cost about $25 including shipping) and have it installed. The AM filter in the original 706 was used for AM only and narrow and wide FM were bypassed.  In the IIG, the AM filter is also used for FM narrow and only FM wide is bypassed. Supposedly, AM selectivity is greatly improved with this mod.  Without test equipment and a before and after measurement I can only say that AM reception is very good with this filter.  Audio quality is good and adjacent AM interference seems minimal. This mod required the removal of the main board.  Don't attempt if you have any doubts as to your abilities to unsolder the old filter, solder the new filter and replace the board.

UT-102 VOICE SYNTHESIZER (Plug and Play.)

FAN MOD

One of the frequent comments about the 706IIG is the heat buildup.  The fan only runs in transmit or when the internal temperature rises to a certain point.  A simple mod of installing a resistor between the 12V power and the fan keeps the fan on slow all the time and then it kicks in to high during the above circumstances.  Mod seems to work fine and definitely keeps the heat down.  (Fan Mod here.)

EXTENDED TRANSMIT and SELECTING THE CW NARROW FILTER IN SSB MODE

There is an article covering these by KV5R.

Other good/neat features:

    IF Shift
    Easy interfacing through the ACC, Digital and Rig Control ports.
   All-mode squelch
   Built in FSK (although I don't know many who use this anymore.)
   Lock button.  (SGC could learn from this.)
   The Noise Blanker seems to work very well (at least in SSB). 

What I don't like. 

    No AGC OFF position.  
    The radio gets HOT!  Maybe some additional venting for better air flow? The fan is quiet so I'd feel better if it ran all the time.  There is a mod for this.  I'll post if I perform the mod and it works.
    No way to shut the internal speaker off when using boomset or interfaces except by headphones or plug.  This could easily have been added in software.
    Scanning should default to the selected scan list and resume if powered on and it was set to scan when powered off. 
    There should be an option to 'stop on activity' instead of 'must resume' during scan.
    Need a control for mic gain.
    Although I don't see how it could be done with so little room, I really hate modular mic connectors.  A screw-on would be much more durable for a portable rig.
    How hard would it have been to set this rig up for satellite use?
    Having to buy all sorts of options to get the radio to where you would have liked it to be when purchased.  (TCXO, filters, DTMF mic)            

   Windows Software for Automatic Link Establishment (PC-ALE)  
           Uses rig control and soundcard to implement automatic link establishment on common radios.  Stay tuned for results.

   Rig Control Software
        There are many programs for computer control of rigs.  This is not an endorsement of any, just some results of searching:
            The Commander

   Interfaces
        The ICOM interface is expensive.  A simple interface can be made using a MAX232.  Total cost should be around $10 for the frugal builder. If you happen to have a commercial radio programming interface available such as the Price Industries P96A, you can also use that.  Connect pins 11 and 12 on the DB-25 together and then to the tip of the 1/8" plug.  Pin 25 is ground and goes to sleeve.  
            W8WWV CI-V Interface  
            www.pdsengr.com/products.htm  - Interesting IR remote CI-V interface

   AH-4 Antenna Tuner
        Works well, quick.  Can be used with longer feed line and control cable than the SG-237.

   Interfacing with the Rigblaster
        The West Mountain Radio site has info on interfacing the 706 with the Rigblaster.  You can jumper the box to reverse the modular mic and rig connections.

   Microphones
        My understanding here is that there is +5V on the mic line and a .47 mFd in series with the audio line will allow you to use other than ICOM microphones. Heil has some additional info.

Mods, manuals are available at www.mods.dk .