[Icom] Another 756Pro mod needed- MW sens

Wed, 22 Jan 2003 11:03:51 -0600

Use your Kenwood or Collins for this out of band receiving? Maybe the Pro
III will have this change? :-)

Andy  K5VM

----- Original Message -----
From: "VE6JY Don Moman" <[email protected]>
To: <[email protected]>
Sent: Wednesday, January 22, 2003 11:31 AM
Subject: Re: [Icom] Another 756Pro mod needed- MW sens

> Well, an external preamp may well have to be used, but it irks me to have
to
> do so. I purchased a quite capable general coverage receiver that is at
> least 20 - 30 db less sensitive below 1600 khz than it should be.  Just
tune
> across a moderate signal on 1600 khz and watch the signal drop as you go
> past 1599.99.  They didn't even get the specs in the manual right - 1.799
> should have been 1.599 mhz. Yes I know they have a standard disclaimer
that
> receiver specs are not guaranteed on certain frequency bands.  And I have
> several 756Pro's that all behave the same.
>
> There is no technical reason or need to reduce gain in that region. In
years
> past, when radios had much less dynamic range, somebody noticed they could
> get overload on mw easier than any other band, so in their "wisdom"
decided
> to make that harder to have happen and embarrass the dealer,
> manufacturer,etc.
>
> I have a rural location with low noise and am about 100km from the nearest
> MW transmitter (however they are still very strong, producing several
volts
> of RF on some of the wires). Weak signals from Europe or Australia are
> weak - and the 756Pro hasn't got what it takes to hear them.   My mw
> sensitivity  modified Kenwood R5000 is superb down there, and the R71A not
> far behind. Even the Collins HF-2050, which isn't super sensitive, still
> does quite well. But they don't have that nice spectrum display.......
>
> 73 Don
>
> ----- Original Message -----
> From: "George, W5YR" <[email protected]>
> To: <[email protected]>
> Sent: Wednesday, January 22, 2003 15:41
> Subject: Re: [Icom] Another 756Pro mod needed- MW sens
>
>
> > Seems to me that the easiest "mod" would be to use a simple external
> > preamp in the Receive Antenna input . . .
> >
> > Gain is reduced in that frequency range for a number of reasons . . .
> > I am curious as to what  application requires additional gain below
> > 1600 KHz.
> >
> > 73/72, George
> > Amateur Radio W5YR -  the Yellow Rose of Texas
> > In the 57th year and it just keeps getting better!
> > Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
> > K2 #489  IC-765 #2349 IC-756 PRO  #2121 IC-756 PRO2 #3235
> >
> > ----- Original Message -----
> > From: "VE6JY Don Moman" <[email protected]>
> > To: <[email protected]>
> > Sent: Wednesday, January 22, 2003 2:21 AM
> > Subject: [Icom] Another 756Pro mod needed- MW sens
> >
> >
> > > The stock 756Pro receiver is rather numb on mediumwave (<1600 khz)
> > since
> > > neither preamp functions down there and there is a fixed attenuator
> > in that
> > > BPF stage. I have removed the fixed attenuator but it was only a
> > small
> > > improvement. What we really need is to enable the preamps to
> > function down
> > > there. This should be, at the very least, a menu option. Of course
> > it isn't.
> > > I am always annoyed when manufacturers decide what gain I need to
> > use....
> > > and ICOM has had a long history of doing that.... but at least
> > earlier sets
> > > were easier to modify.
> > >
> > > Anyway has anyone managed to enable the preamp function below 1600
> > khz? If
> > > so, I'd sure like to know more...
> > >
> > > 73 Don
> > > VE6JY
> >
> >
> > ----
> > Your Moderator: Dick Flanagan W6OLD, [email protected]
> > Icom Users Net: Sundays, 1700Z, 14.315 MHz
> > Icom FAQ: http://www.qsl.net/icom/
>
> ----
> Your Moderator: Dick Flanagan W6OLD, [email protected]
> Icom Users Net: Sundays, 1700Z, 14.315 MHz
> Icom FAQ: http://www.qsl.net/icom/