[ICOM] 756 PRO II BCB sensitivity

[Cecil Acuff]

Thanks Don...I'll explore some more!

Cecil...
----- Original Message ----- 
From: "Don Moman" <ve6jy at 3web.com>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Friday, February 04, 2005 11:50 AM
Subject: Re: [ICOM] 756 PRO II BCB sensitivity


> The fixed attenuator built into that <1.6 mhz filter section isn't too 
> hard
> to bypass, if you can handle tiny smt work. I have done this on both of my
> PRO's, but not the PROIII yet (it still needs it removed). There is a way 
> to
> trick the preamp -  Dallas Lankford came up with this idea - by cutting 2
> traces and reversing them, so the preamp is on when you turn it off, you 
> get
> the idea.  I can see where to do it on schematic but haven't translated 
> that
> to where it actually needs to be done on the board.  In this respect, the
> PROIII may be easier to mod as the preamps are mounted on a daughter board
> above the main board. I have not yet attempted this mod on either the PRO 
> or
> PROIII.  It would have been so simple, at the design stage to allow the
> preamps to be enabled, but as usual, we are stuck with what the designers
> think should be sufficient.
>
> At least if the internal att is bypassed, one can add external 
> amplification
> without loosing 10db of precious headroom, but letting the internal 
> preamps
> function would sure be handy.   I did break the RX line internally after 
> the
> TX/RX relay and bring it out to the rear, so I have true TX antenna OUT 
> and
> RX IN  (like older ICOMs with the little phone plug jumper) which adds a 
> lot
> of flexibility for external amplification and filtering.
>
> 73 Don
>
> ----- Original Message -----
> From: "Cecil Acuff" <chacuff at cableone.net>
> To: <icom at mailman.qth.net>
> Sent: Friday, February 04, 2005 17:19
> Subject: [ICOM] 756 PRO II BCB sensitivity
>
>
>> Greetings,
>>
>>         Anybody been successful at restoring the full sensitivity on the
> BCB
>> and LW.  I would be interested in how it was done.  I have seen info on
> how
>> to do it on the 746...as well as managing to activate one level of preamp
>> functionality.
>>
>> Things pretty deaf down on LF for us beacon chasers....
>>
>> Cecil...
>>
>>
>> ----
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>>
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
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>