The AM Forum

http://home.comcast.net/~ke1gf.web/706_Mods/index.html

Nice Job Bill !!

It sounds great from the mobil setup.

Bill:

There seems alot of different mods out there for the 706MkIIG.  Can you help me sort it out and figure out the best way to improve both AM reception and TX on my stock IIg?

Thanks

- JT

As usual -  Nice Job, OM!  

You definately spent the time to do the finer details. Lots there. And,
the documention and circuit mod descriptions are EZ to follow. This
write up will probably be around for years as the standard for
modifying this rig. When the web robots get it, it will help lots of guys
outside the AM community too.  It's in the same class as the DUQ
mods for the FT-1000D.

Make sure G gets it into the archives for EZ access.

73,
T

TJ the best way to improve the TX audio is do my audio stage mods. The tough part about the 706 is finding the FL-102 IF filter for better RX selectivity. I have two of them here and I have two 706MkIIG's. Keep looking on ebay, they pop-up and get scooped up quick.

I would like to find a filter that would pop into the 706MkIIG for 6KC am selectivity, but the problem is that ICOM never provided provisions in configuration menu's of the 706 for a more selective AM IF Filter. You wouldn't even need to perform any circuitry changes to the radio if the software could do it, there's nothing missing in the radio to do, I just have to hack the rig to do the job...

I have demonstrated that it is possible to place a better filter into the radio with mods, but no company will manufacture a filter for the rig if it requires serious mods to make it work.

-Bill 'GF

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5795337655&ssPageName=MERC_VI_ReBay_Pr4_PcY_BID_Stores

Every receiver I have seen with crystal or mechanical filters do not take advantage of the total performance of the hardware. I have found it takes at least 2 filters cascaded with shielding performance to match. Say you have a rX with 100 dB of dynamic range and a filter with ultimate rejection of 70 dB
guess what is the limit for performance.  Harris and Racal both use dual filters in the first IF for roofing. The filters are located in different shielded modules
to take advantage of the possible performance. Cascading filters in the second IF will also improve performance as long as the passband ripple is acceptable. This helps when there is noise or QRM.  gfz

Anybody thinking of doing my mods in the future...

snatch this up: http://cgi.ebay.com/Icom-FL-102-6kHz-AM-filter-9mHz-6dB-Excellent-shape_W0QQitemZ5826029893QQcategoryZ48702QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

The price is good...

-Bill 'GF

Hey Crew, sorry for the downtime I moved my site over to my comcast webspace.

-Bill 'GF

Okay, here's the new address.

I don't suggest that you do this mod until I find out what went wrong with the 706 that I gave to Rich K1ETP.

http://unix-srv.1gflabs.com/ke1gf/706_Mods/index.html

-Bill 'GF

It seems that the latest link isn't working, is there any way to view these modifications? Also will they work on the older IC-706?

Bills web  site is no more, the only place I see him on line is Skype.
ke1gflabs is his Skype name...

Good Luck!  I just checked and he appears as being on line.

There is nothing wrong with my mods, you just have to run a little bit more than 8 watts carrier on AM.

http://webpages.charter.net/1gflabs/706_Mods (http://webpages.charter.net/1gflabs/706_Mods)

-Bill 'GF

Hi Bill,

Have you tried running audio to the modulator input via the accessory jack?

Do you happen to know if this modulator input goes to the same place as the microphone audio?

Thanks

Phil - AC0OB