[Icom] Another 756Pro mod needed- MW sens

Wed, 22 Jan 2003 10:31:49 -0800

The suggestion about turning the antenna tuner off is exactly what I had to=
=20
do with my 765. I was appalled at the lack on sensitivity on the broadcast=
=20
band until I shut off the tuner & that brought the signal of a STRONG local=
=20
station from about S-3 on the meter to 20 over S-9.

73 - Larry W=D8NFU
[email protected]

At 05:31 PM 1/22/2003 +0000, you wrote:
>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/